Bent wrench used to access exhaust manifold bolts. (The catalytic converters are in the way.)
Symptom: Totally non-functional cruise control. (Actually lots of problems, but we're only talking about this one right now.)
Treatment: Open hood. Hmm, isn't there supposed to be a cable going from the VDO vacuum actuator to the throttle somewhere? Old cable was ripped out by the roots, as witnessed by the frayed cable end and plastic bits still stuck in the actuator. Order new cable from George Murphy. Cable arrives and, unlike many of my experiences in repairing this near-beater, fits perfectly. Thanks George! Lube up throttle linkages and adjust cable to just remove slack. Go for drive.
New symptom: Wacky, spastic cruise control. (OK, I was kind of expecting this—hoping for it really, since it means that it was nearly working.)
All symptoms (and prior history/advice) point to brain box. I know that some can be fixed, and that if not, both repaired and re-engineered units are available, my choice, so I shouldn't be afraid to try drastic measures. We'll try the cheap fix first.
Now to remove brain box to give it an electrical enema. Heard about tricky bolting-on problem from the list and can confirm same from lying on my back under the dash. Box visible easily, mounting bolts not so. Dim bulb flickers on: "Hey, I only want the box out so I can bend open the ears and remove the circuit board. There's the ears!" Bend open ears in situ and circuit board drops into my hand. Nasty little bolts and box still in place, looking shocked and disappointed.
Board looks OK. (All analog, with a myriad of resistors, capacitors, diodes, and transistors, plus a couple of relays and one [I assume] transistor array. [I didn't look it up.]) No scorching. Solder joints look infinitely better than the 10-year newer ones I saw in my 560 SL's lamp-failure module, which were causing problems. Re-solder all joints anyway.
As an EE, I'm aware of the little-known fact that some types of capacitor routinely fail due to age, most particularly aluminum electrolytics (which should never be used in anything that's being built to last the ages). There's exactly one of these on the board, a 47 µF 16 V unit. (Looks like VDO almost got it right.) Yank it and throw it on the leakage tester. It takes a long time to charge up. Not a good sign. Throw it on the RLC bridge. Capacitance good, but dissipation factor is 75%, which is really bad. It has far too much series resistance, and can't really function much as a capacitor anymore. Throw crap part away. Rifle junk box for a replacement. Found and installed, no problem. (Yes, I tested it first.) Yank a couple of random capacitors of the other types from the board and test, all good.
Time for a test drive. Temporarily re-install board and drive off. Cruise control functions very well! (A little more noticable in operation than the newer servo units in my other MB's, but that may be normal. Anyone know for sure? Or, there may be other problems, even that replacement aluminum electrolytic I just stuck in. OTOH, it works as well as the factory one in my pickup truck, so who knows.) Regardless, it's now functioning acceptably well. Time to button things up and move on to the next problem.
(The girlfriend's complaints about the Escort are two: no cruise control and no air conditioning. Now the 450 SL has both! Definitely a plus in the weaning process.)
I was able to resurrect the car's non-automatic (but electric) antenna, which was very gummed up with (no doubt) residue from previous lubrication attempts. I had to remove the mast from the motor, and once apart I glugged lacquer thinner down into the mast and repeatedly extended and collapsed it. Repeated until no more goo came out, in the thinner or sticking to the mast. It took awhile. That thing was filthy nasty inside, and very sticky before the cleaning.
Then reassemble. (In this case, I also had to replace the pinch roller bearing in the motor assembly, which had rusted solid. Boy, that was fun! A local bearing house was able to measure the pieces [I had to use a hammer to break it apart] and supply an exact replacement, down to the markings on it. [625, if I recall.] Not cheap, but way cheaper than another Hirschmann.)
[This antenna is now residing in our 250C convertible, and works great.]
The car had very poor acceleration off the line, and the transmission made a whining sound until it was up to speed. It turned out the stator splines were sheared off of the front of the transmission, causing the torque converter not to multiply torque at low speeds. The front piece of the transmission was not affordably available. (Though in retrospect I think it could have been, via junkyard channels.)
I replaced the transmission with a boneyard (Aurora Auto Wrecking in Seattle) unit for $350 and a whole lot of screwing around. 'Twas a labor of love, you see, and I was unemployed at the time... (OK, I spent a little more because I replaced anything rubber that I could reach during this job. Seals, flex disks, subframe mounts, etc. At a bare minimum I'd do the rear crank seal and the front transmission seal. The 'new' transmission even had a 90-day warranty from the yard, and so far it's been working very well.)
I've looked at the 126's display module, and it's too wide to go in there. I've also checked out the auto-parts stores' thermometers, and the LCD's are all way too tall to go in, plus there's the power and backlighting problem to solve (don't want batteries). So, what I'm left with is cutting (carefully!) the LCD out of the 126 display module and running extension wires back to the module, which will probably be screwed to the back of the instrument pod somewhere.
On my wife's '76 450 SL instrument cluster there was a clear window directly over the steering wheel, about 2" by 1/2" in size. It was plugged with a piece of styrofoam with the front painted black. This plug slides in and out freely. In appearance it looks just about like the window that our 300 SDL has for its outside thermometer. (My wife likes this thermometer.) Obviously it's for some sort of display that a 450 SL does not have, but some related car that uses the same instrument pod does. I'm told it's for a column shifter PRNDSL display, probably for the 116 as that car shares the same instrument cluster.
From a boneyard, I got a 190E temperature display unit, and a sensor (with cable & connector) from a 126. (Long story here, but according to the dealer the only difference among the temperature sensors for differing models is the cable length. Perhaps a 190E sensor would fit too, but I'm only able to relate what I did.) Were I starting from scratch, I'd get both pieces from the same 190E and make it work.
The display unit has a "Y" cable coming off of it, one end a 2-pin that mates to the sensor, and the other a 3-pin for which I had to get the mate from the dealer for $4. (You'll also need a few inches of stranded wire, a small drill, and some soldering equipment and experience.) The brown wire to the 3-pin is Ground, the center wire is Illumination, and the other end is Accessory power.
I mounted the sensor in the front grill of the car near the AC receiver/drier. This is not a great location, and I may move it later. The thermometer works great so long as you're moving, but when standing it gets too much hot engine air there. Perhaps under the license plate or something like that will be better. The sensor needs to be mounted so it doesn't touch anything, is shaded, and gets as much fresh air as possible. It should also be protected from damage. Not easy!
I then removed the steering wheel and instrument cluster, and routed the sensor cable through the engine compartment up to the rubber grommet through which all the vacuum lines go. This is an odd thing with many 'tits' on it, through each of which one line goes. There was one unoccupied site, which I nipped off with wire cutters. Then, I carefully unclipped the plastic shell from the sensor connector so that the pins and wires could be pushed through the grommet. (Note how the pins go into the shell, although I think they could be switched with no consequence.) From the inside, I pulled the cable the rest of the way through and routed it so that the windshield wiper arms wouldn't mangle it. There was still plenty of length to reach the instrument cluster. I then put the connector shell back on.
The instrument cluster has to be taken partially apart. The speedometer and the triple gauge unit have to come out. The back of the gauge unit is a printed circuit board. Near the upper-right illumination light on this PCB are three solder pads from which Accessory, Ground, and Illumination signals can be tapped. I just soldered on three 6" wires to these spots and ran them out a hole I drilled through one of the blank spots in the PCB near there. (I gleaned this information from the Haynes schematic for this car.) I nipped them to length on the outside and soldered on the new connector, then I reassembled the cluster.
The 190E display unit is too wide for the opening. It has a wide plastic bracket with a couple of large holes in it, probably for odometer trip reset and dash dimmer buttons. I cut the bracket with a jigsaw (one of the small, high-speed buzzing desktop types) so that about 2/3 of each large hole was gone. You need to be careful doing this because the LCD's in these things are fragile. You could probably also do this with a small vise and a coping or hack saw. The display unit can then be wedged into the opening. I think the opening tapers slightly, because it gets tight before it bottoms out. You should see that the display is easily visible from the front of the cluster, and is seated correctly. I then cut a small piece of metal strapping and bent it into a "Z" shape, drilled a hole at each end, and used small sheet-metal screws to attach to the existing mounting holes in both the display unit and the instrument pod. This keeps the display from backing out of the hole. I could have used two straps, one for each side, but I didn't bother.
Finally, I just plugged everything in and put the car back together.
It worked! It looks great, works fine (except when not moving), and even lights up at night, and dims (!) with the dash lights.
The only bad thing is that this thermometer is a °C unit, but maybe she'll get used to it. Or I'll have to get a different display, which is the big reason I used mating connectors. The swap will be easy if I have to do this.
Headlight warning buzzer: The '76 doesn't have one of these, and my wife's already left the lights on three times that she knows of. No dead battery yet, though! This one is fun, but pretty easy, and can be done entirely through the instrument pod opening. You need a 12 V relay, a small one is preferable. Mine was an old junkbox unit that only needs 12 mA coil current. Anyway, tap into the two wires going to the key-switch present connector (on the front of the ignition switch). I think it's green/violet and brown. (The brown is ground.) Connect one contact and one coil wire to brown, and the other contact to green/violet. Run the other coil wire to the K terminal of the headlight switch. (I think it's K, it has three violet/white wires going to it and is for the parking lights.) Now whenever the parking lights are on, it acts as if the key is still in the ignition, and buzzes when the driver's door is open. The nice thing is that done this way there is no warning if the engine's on when you open the door.
Fog lights separate from low beams: I think the euro models have these circuits separated, so you can turn on the fog lights without the headlights being on, and so they don't go off when the high beams are on. Anyway. I like them being separate. Pull the fuse block out and turn it over. On F19 are a yellow and a yellow/green wire. Cut the yellow/green wire loose and attach a ring terminal. Attach it to F15, the one that's unused. (Hence my speculation about the original intent for the fog lights.) Put back fuse block. Switch the 8 A and 16 A fuses of F15 and F19, so that the low beams have the 8 A fuse. You can be nice and re-label the fuse map with a pencil.
Rear fog light: The euro models have these, which in effect turns on one rear brake light if the light switch is pulled out two clicks. Useful under very heavy fog conditions. You need to run a wire to the back of the car from the NS terminal on the rear of the light switch. You also need to ground terminal 31 (the last one of four) on the rear of the switch, and make sure you have the little light bulb in the switch under the knob. Mount a socket for an 1156-type bulb so that the bulb will be just behind the tail lamp 5 W bulb on the driver's side. This sounds harder than it is. Connect the new wire to the bulb's center contact, the outer contact is probably already grounded if you bolt the socket to the metal piece of the taillight assembly. Now when you pull the light knob two clicks out the extra bulb comes on, and the little red center of the switch lights to remind you to turn it off later.
My wife has complained about the steering wheel ever since she started driving this car. Too big, can't see over it, etc. We had the seat height adjustment set to the top setting already, but it wasn't enough. It felt too soft to me, and I seemed to list a little to port whenever I drove it. I felt around underneath and found a broken spring end. Aha! I searched the archives, and found that it appeared that you can get a new lower spring frame for about $80, which sounded OK to me if it would cure the problem. I called the dealer, and he seemed to think the same, until he looked. $600! He apologized, and understood when I declined to purchase one. Apparently the price varies a bit from car to car...
So, this weekend I took the seat out, and took it apart. It comes apart pretty easily, the worst part is prying open the hog rings, which I accomplished with a pair of wire cutters. (Don't squeeze hard enough to cut, but just enough to bite into the metal so they don't slip when you pull hard.) Then the cover just slips off as described in the archives. I was surprised to find the horsehair pad in good condition. Not one, but two of the five springs were broken. I took some heavy strapping metal, about 1/16" thick and made a splint for the springs. These I hammered over the springs so that the break was out in the air by itself. Easier might be to use a 1" piece of wire conduit, slip it into place like a ring over a finger and flatten it with a couple of hammers. (I didn't have any conduit.) I then brazed the spring together and the splint to the spring. This tricky, because too much heat can wreck the springs, but I eventually got it to work.
The springs seemed collapsed a little, so I pulled hard and stretched them out a bit so the seat would be thicker when re-assembled. I also laid a couple of old towels over the top of the horsehair pad for extra height. Finally, I went to the rag bag to get a pant leg and some stuffing for it. Weren't any pants in it, but the jeans I was wearing were blown out at the knees, so I cut one the rest of the way off of myself and used it. This seemed to amuse my wife. I stuffed it like a sausage with rags, and tucked it into place into the springs. (The profile of the springs is like a '?' in shape, with the dot at the back of the seat.) The roll of rags tucks nicely into the crooks of the springs. I then reassembled the seat and reinstalled it. Regular pliers were all I needed to re-clamp the hog rings, and I hammered the channels shut a little more to hold the cardboard in place better so the cover wouldn't pop off any more. While I was there I cleaned and greased the tracks.
Success! The seat is much taller now than before, and firmer. It's more like a foam seat, and this is due to the rags stuffed under it. I might have overdone the stuffing a bit, but time will tell if this needs correction. My hair now brushes the hardtop with the seat set to the high position, versus being able to wear my fedora without interference, but my wife is very much happier with it. She says it's a lot more comfortable to drive than it was, and she doesn't think that the steering wheel is too big anymore, nor does the angle hurt her wrists anymore. Also, she used to keep the back set uncomfortably forward in order to gain more eyeball height. No more.
I topped off the job with a Becker-ectomy and added a (used) Alpine CD player and some rear deck speakers. She may end up pretty happy with this car!
Now, I know that on the diesel engines there are O-rings on the stinger through the filter that can harden and leak, and this will reduce the oil pressure. Easily fixed. Does the 450 engine have a similar easily-fixed problem? I'm really hoping that this isn't the sign of something really expen$ive about to happen.
Oh, the odometer reads 140 kmi. I believe this to be reasonably accurate.
I suspected the worst, but decided to replace on the 'what the hell' basis the seals on #2 only. The seal kit for half the engine was something like $6 at the dealer, and the valve spring compressor was about $50 at Parts Plus, I think the tool rack was KD Tools.
KDT-3087 K-D TOOLS VALVE SPRING COMPRESSOR- $56.06 Tool compresses valve springs on most overhead valve engines including GM, Ford, Chrysler, Nissan and Toyota. Jaws adjust to fit over spring retaining washer. An adjustable handle allows easy clearance in tight areas. GM adapter included. use no. 3269 Fulcrum Rail if overhead cam is not available.(I had to do some searching for a compressor that is similar to the MB model shown in the manuals. None of the other styles will work. Even at that I have to tie a wire around it to keep it in shape while using it, as it's not quite right for that engine. It has a foot-long lever-over handle, two hooks that hook around the cam, and a couple of arms sticking out that press against the spring. This is similar in form to the one pictured in the MB service manual, but of much lesser quality. [I went to the friendly local dealer and handled the one on their rack. Its price was stunning, but it was made out of tool steel instead of the stamped sheet metal of the one I bought. It was very nice.]) I used the compressed air trick to hold up the valves.
Anyway, a couple of hours later the smoking was GONE!
It still uses some oil, and I probably should do the rest of the valve seals someday. Also, if indeed the valve guides are also worn it will eat the new seals in a relatively short time.
In this case, though, as 'short' is at least a year based upon the evidence I don't see any reason not to just repeat this trick the next time it gets bad.
Getting the thermostat out is always fun. I ended up just removing the alternator. This is easy, and makes the rest of the process very easy. I just left the belt loose in there, sitting on the cross member. It didn't move. I hooked up a battery charger to the car to make up for the lack of charging, since it was going to be running for half an hour or so.
I had the old, defective, thermostat still. (It opened too cold.) It was a lot easier to wedge open than the SDL's thermostat, I didn't need the valve spring compressor. Just needlenose pliers, and a suitable length of .357 shell casing. With the pliers you can separate the two halves of the thermostat. Then you just slip the brass collar over the pin and reassemble. Voila! Instant flushing tool. (You can't just take the thermostat out, because the bypass passage will be left open and you won't get circulation through the radiator.)
The other tool you need is an upper radiator hose that's tee-ed into a garden hose. From before I already had something, which was a suitable length of hose from a junker, with a fitting poked through the side.
At this point, you follow MB's procedure. Run the engine with the heater on defrost and fresh water running through the engine, for five minutes. (I left the radiator drain open, and the cap off the expansion tank. Water ran out of both.) Then, close the cooling system and put in the 2.5# of citric acid, dissolved in a gallon of water. Top off with water. Run for 15 minutes. Then, drain and repeat the fresh-water flush for 5 minutes. Close her up and fill with fresh coolant. (MB stuff preferred, of course.) Don't forget to log this procedure, so you can tell when you need to flush again. (Hopefully on schedule, before you would need the acid again to clear out corrosion.)
I have verified the cold-start injector system, and I did disassemble/clean the warmup fuel regulator. It seemed OK. I was just wondering if the idle control valve leaked enough (when hot) that the idle control screw has to be turned down too much to idle well when cold.
Also, is this valve adjustable? It has an odd notch in the top that would imply this.
This morning I was able to wedge the bottom of the heater box back into place. It is not yet attached, and I had to cut another harness wire in order to get it into place. What a mess! I will have some difficulty getting the retaining clips back into place, and the heater box reattached to the firewall and plumbed in.
But while I was there I was able to restore the right-side vacuum valve (that controls coolant flow to the heater core) to functionality, so at least that will work correctly once it's all back together. That was more of an annoyance than you would have thought, chiefly because my wife gets colder than I do, and to turn on her heat (when I was driving) I had to turn mine on too.
I'm now pretty much back to the point I should have been, had I merely taken the car apart far enough to do only what I'd originally intended. I now need to install the dome light relay, finish the crack repairs on the dash, and install the dome light switch into the dash.
And it works! The dome light now acts properly. The transistor circuit consumes negligible current when the lights are on, and truly minuscule (leakage) current when they're off. A relay might draw less current when off, but I didn't have any relays to spare. And they're bulky, and draw more current when they're on. The transistor solution is superior for this use.
I also dug out one of the repaired cracks (which was cracking again) and re-filled it. I don't think the original job had been done correctly, the other cracks have all been filled for months and have not failed.
I profiled the remaining cracks, using a small sharp chisel to flatten the crack to the surrounding level. At that point, I used the broad tip of a semi-sharp carbon-steel butter knife (one of my favorite tools, btw) to randomly scrape across the cracks so as to propagate some of the pebbled texture into the smooth filled cracks. I don't know how successful this is going to be, but it appears to me that getting the texture correct is the most difficult part of this repair.
All these other items will get painted next. I'm hoping I have enough paint left to hit all the vinyl surfaces. This will refresh the (rather sun-baked) interior color, and should improve the overall appearance quite a bit.
I got all the paint (and painted) crap out of the warm side of the garage so my wife may resume parking in there. Things are stacked on and around the car now, so I really need to get to reassembling. I did start fiddling with the AC switch, and routing its temperature probe.
I need to get some black cotton webbing to glue on the leading edge of the dashboard. What was sewn there has all rotted and fallen off. This is an important anti-creak component! That is, I believe, the last thing required before reassembly may begin. Once I can begin reassembling, I'm hoping the job will go quickly.
With that done, I began reassembling the dash. Unfortunately while putting the ducting back into it the dash cracked again, in a new place! And two of the existing cracks at the very front opened up a bit too, due to (avoidable!) stress I put on it while crimping the duct retaining ears down. This is going to get old. Fast. I think it can be repaired just like before, so I'll try that, and I think if I can get it installed intact it'll hold up to normal stress, but...
Pretty depressing. But onwards!
The two posts that hold in the switch bezel had speed nuts on them, which broke during removal. So I threaded the posts 4-40, and used real nuts on them instead.
I reassembled the shifter as well, now that the legend has been cleaned up. And, I recovered the wheel that was serving as the spare for the new 560 SL, it got a steel wheel spare (from a 116?) that I had. I had to scrape up a set of steel wheel lug nuts for it.
The dash is getting a bit scarred at the edges, and smudged all over. At this point I think it'll still clean up fine, with a bit of airbrushing too. With luck it'll go back in without further damage, and seat properly.
The dash is now hooked up, as are all the ducts and HVAC controls. It still doesn't seem to fit in all the way, but you'd never know it from the outside. Maybe this is right after all? Regardless, I got tired of fooling with it, so now it's in. An adjustment of the center flap link rod made the center flap work correctly.
I still have cracks in the dash to re-repair, and the whole thing is very dirty. This will all be done in-place, no more dash removal!
I was going to install the instrument cluster, but found when I turned it over for the first time in a year that the cracking of the clear window was much worse: all three windows exhibited problems, some severe. It appears that sitting alone was not good for it. This would have been very depressing except for the fact that I had recently gotten a spare instrument cluster from a 116, which happens to be exactly the same part. (In fact this cluster has already sourced a tachometer movement into Jill's new SL.) I cleaned this replacement window and got the old one out of the cluster. Unfortunately one of the plastic posts that holds the cluster together broke off, so it is gluing up now. This is not the first such damage, old plastic can be very brittle.
At this point in time I tried to install the dome-light bearing windshield top moldings (from a 560 SL), only to find they don't fit well. Apparently a 560 SL has the top rail relieved to make room for the light bodies. Without this relief, the moldings don't seat fully in place, and the light bodies tend to protrude a bit from their sockets. This is very depressing, considering that adding these lights is what prompted the disassembly of the car in the first place. Not that the situation looks that bad, really, but the current effect is more GM-like than I care for! It remains to be seen what, if anything, I'm going to do about this.
I reassembled the shifter and placed a box in the car for me to sit on. Then I slipped the steering wheel into place (unsecured), and remembered to put the drained coolant back into the car. (One of the steps to removing the heater core.) With this, the car was ready to fire up, which it did with only about twice as much cranking as a normal cold start. It started and ran normally, so I put it into reverse and backed it out of the garage. For the first time in a year and a half or more. With the car out of the garage, it was much easier to swap off the two snow tires that were still on the front from way back when. Also, the doors swing all the way open outside, making for easier access. And in the sunlight the interior color can be examined properly. It's looking pretty good.
With the car outside, I then began fitting the console into place. Finding one of the screw mounting holes broken out (now I remember!) I took time out to use Shoe Goo to glue the little pieces back in place. Then I potted the area in Shoe Goo, and laid strips of aluminum reinforcement (pop can material) over the area to strengthen it a bit.
All of this work occurred in the warm sun. In fact, it was getting a bit on the hot side. Sitting back on the rear deck for a bit of a rest, I noticed that the filled cracks in the dash were very prominent! Oh no! The thermal expansion of the dash was forcing the filler material to protrude noticeably. There is no way that this crack filling experiment can be considered a success. It still looks decent, but isn't really acceptable. At least the dash cap repair is there as a backup plan.
Well, with lots of time on my hands (and no income) I can at least try a repair. I was able to make a small piece of copper leaf using hammer, anvil, and a bit of romex wire. This I rolled into a small tube, which I then soldered the (now-separated) pieces of the tube into. With some filing it will still slide into the evaporator housing.
Next is the difficult proposition of filling it with something. While I do have two cans of R12 left, I really hesitate to crack one open for a job as dubious as this one. I unsoldered the tip of the tube, and got it open a bit. Next, I researched pressure curves of various refrigerants looking for something similar to R12 around the freezing point. Didn't have a whole lot of luck using my CRC handbook, or an old refrigeration 'bible', so I thought I'd just see what pressure was in one of my cans of camping fuel (a propane/butane mix). It was some 55 psi at around 60 degrees, which seemed to be close enough to R12 to give it a try.
I finally got around to making an official camp fuel tap, prior to now I just clamped an R12 tap to the side of a can and pierced a hole in it. However, some time ago I'd procured a thrift-shop camping stove from which I intended to steal its fitting. With the stove tap, a piece of 5/16" fuel line from the liquidator's, a spare R12 fitting from the junkyard and a couple of clamps, I was able to make a tap. With the cans of fuel now somewhat reusable, I can afford to experiment with this thing a bit.
Taking another R12 fitting, I drilled a 1/8" hole through one of the side flats. The intent here is to fit a plunger through this hole to hammer the tube end flat once the thing is charged. With any luck I can then solder the end shut without the gas escaping. I think I'll be trying this outside! Next I'm going to fill the non-flare end of the fitting with Shoe Goo, through which I will drill a tight hole for the tubing once it's dry.
This ain't easy.
I also Shoe-Goo'd the non-flare end of my to-be-charging fitting, and set it aside to dry.
I vacuumed and then charged the tubing using my R12 AC gauge set and tools, using butane/propane camp fuel as a charge. This weighed in at about 35 psi at ambient temperature, which was enough (barely) to let the switch actuate. I used fence pliers to crimp the tubing flat, and then soldered the open end. The charge was still trapped in there, and then I adjusted the sensitivity screw on the bottom of the thermostat to try to get the switch actuation range to match that of my intact (but unsuitable) spare thermostat.
I had a few leaks, and the charging fitting popped off a time or two, but I was finally able to get a charge in. It may be a little 'hot' in that there may be too much propane (pressure). I'm not sure I'll get proper thermostatic action as a result, but at least the switch cycles on when you turn it on, so the AC compresser should run.
With the tubing charged this way, I then used fence pliers to pinch the tube flat where it goes into the charging fitting. Then I rushed outside and soldered the end of the tube shut. After this, the switch still turned on, and even several hours later it was holding a charge. Soapy water on the end and the soldered splint showed no leaks.
So I installed it. We'll see! The spare thermostat turns on with about a 180° turn of the knob, the recharged one is less than 90° to turn on, and there was insufficient range of the adjusting screw to bring it into line.
Also installed is the HVAC panel and the ashtray. What remains in the area is just the stereo. Then the underdash panels, glovebox, carpets, and seats.
The dome light addition has turned out to be flakey, and a bit of diagnosis shows that the TO-92 NPN transistor used to invert the dome light signal to the timer relay is too puny. It appears that the dome light relay needs a burst of ground current to activate, though it needs very little once activated, and sometimes it got 'stuck', drawing 120 mA while not being able to pull the voltage low enough, causing overheating of the transistor. Experimenting with more base drive didn't cure it, so instead I added a second NPN power transistor from the junkbox (smaller than TO-220, but a TO-220 [common] would be fine) in a Darlington configuration. (Common collectors, original E [was grounded] to the new B, and the new E to ground.) This seems to have cured the problem.
I made a schematic of the circuit, for future reference, in Illustrator, PostScript, PDF, and GIF formats.
Next I put in the passenger's-side underdash stuff, including carpets. I also had to glue back into place the one that goes underneath the front of the seat, using carpet contact cement. Then I put the seat in, after vacuuming the area thoroughly. At this point, the car looks more-or-less complete, though there are some more things to do.
Then I put the glovebox back in, which necessitated a side-trip to restore the crimp-on connector for the glovebox light switch that had come off somehow. For now the retaining rivets are not in place, until I can be sure I don't need to get back in there.
Oh no, nothing much left! I rolled it outside the garage and parked in the lawn. Then I washed it! Amazing how good this car looks once its clean. The refreshed interior looks pretty good.
After that, there just wasn't anything to do but drive it in to town to procure license tabs, which were badly expired. This car has been 'down' for a long time, it still had snow tires on it from the last time it was driven, which means something like a year and a half has gone by since it was a useful car. Too long, if you ask me.
The car behaved well. As always when I drive it, I just can't help but think what a nice car it really is. It'll be missed once it is gone, but the 560's are better cars, though more complicated.
I think I have the steering wheel off one notch, but I left the emblem uninstalled for just this reason, it's easy to unhook the wheel and shift it a bit. The AC also doesn't cool, no doubt it's leaked down. Another minor chore to take care of.
Later in the day I needed more window screening (thank you son, for ruining one), so I rigged the baby seat in the back and took him to town to get some more. Another very nice trip: sunny with temperatures in the high 70's. I made him carry the screen. (Making him install it in the frame is probably a bit beyond him!)
The car is almost ready to put the for-sale sign on. I need to do cosmetic refreshing of the bucket area (paint and carpet glue), and that should be it. My dad wants to drive the car a bit before we sell it, but he's due here again in a week or so, the timing should work out right.
Also put the center emblem back in the steering wheel, as the wheel seemed properly centered on the test drive.
I also tightened the steering idler nut a bit, it seemed fractionally loose. The next trip or two will prove whether or not I found the rattle. (I noticed no grotesque looseness of anything.)
While I was there I injected grease into the torn boots on the left tie-rod. Probably should get a new one of those, but so long as grease is kept in there it'll be OK. Just more of a high-maintenance item than it ought to be. It's not worn/loose (yet).
I'm thoroughly pissed off, but I still had them run the ad again next weekend, even though we're going to be out of town. Convertible weather won't last forever, and the machine will take messages. We also added the cell phone number to the ad. We do want to sell the car, after all.
As it was Jill's birthday, we took the car on a nice backroad trip to one of her favorite restaurants. It was a nice trip, and of course the car behaved well. She liked the individual control of heat on her side, and I was pretty fond of the deerspotter headlights. The new dome lights were also very welcome in the dark parking lot for the trip home. We'll miss the car when it sells!
Or maybe we should try an ad in the Wheel Deals?
Mercedes 450 SL Convertible, 1976 $7500 Greenacres
Clean classic convertible, everything works, needs nothing. Refinished interior. Take your honey to Dick's for malts! 162 kmi, See http://cathey.dogear.com/JSLsale.html for more pictures, details. (509) 926-7801
'76 450SL Clean classic conv., everything works. Refinished int. 162 kmi http://cathey.dogear.com/JSLsale.html for pix, etc. Spokane $7500 (509) 926-7801...Stinking web site won't let a car this old be entered. I hate most of these online things.
As the day was hot (90+ °F) I got out the AC gauges. The pressure (and charge) was indeed low, so I topped it off. I found that the low-side Schrader valve was leaking a bit, so I tightened it. On a test drive the vent temperatures got to 43 °F, not too bad.
For some reason the passenger armrest's rear retaining screw came loose. Odd. Unfortunately the door panel has to come off to put it back, but it's not like I haven't done a few of those! Took about an hour to button it back up.
While I was under there I noticed that the bolts for the rear transmission mount were loose. Doh! That could easily explain the heavier thumping noise that had started up in the last year on some bumps. I'd looked before, but never found anything, and trying to locate it by ear always led me more forward than that on the car. (Hence today's foray around the steering.) So I tightened them back down.
One test drive ought to prove whether or not these irritants have been cured, I should find out on my drive to work.
...Yes! Take that, entropy!
I'd been looking for that pesky little rattle since I got the car. Tightening things, looking at things, whacking everything in sight, but I could never get it to act up when I was in a position to see what it was. It feels so good to finally kill that noise. It's amazing, but to me, at least, noises like this really negatively affect my enjoyment of a car. This makes being 'stuck' with this car a whole lot more palatable. You can heed my warning that noises really can telegraph to odd places in the car, leading you far astray from the actual source.
On the drive to work the bouncing was noticably reduced, but still not gone. More work is probably required. Yeah, a bunch colder and windier today, nearly 30 °F less as a high! Good chance of rain tomorrow.
The speedometer needle bouncing is definitely a whole lot better, possibly good enough to stop worrying about doing anything more.
I hate plastic.
The door lock vacuum system is leaking down in only a few hours, I think I'll have to dive into that again.
Divide and conquer. I teed off the rear two vacuum elements in the trunk, we'll see if the doors hold vacuum. The MityVac indicated that the rear might have a tear somewhere (a variable leakdown rate, it actually seemed worse at low vacuum levels), but it's not entirely reliable. (Its release valve leaks sometimes.) The golf tee will give me some good information, in time.
I dug out the foam 'football' vacuum pump I use for cruise control testing. (This is a lot quicker to deploy than the main shop vacuum pump.) I rigged a tee, vacuum gauge, and check valve to the line that goes to the car's vacuum reservoir and pumped it down to 13" Hg. It held rock-solid at that level while I puttered around for awhile, so I buttoned up the car. We'll see how it reads tomorrow, I suspect that (of course) the leaking is not in the tank but it'll be good to formally eliminate it as a suspect. I'd feel pretty stupid tearing into the car only to find that it was the tank all along!
...After work I checked and the vacuum was still solidly at 13" Hg. I think I can safely say that there are no leaks there. Will check again in the morning to be sure.
Aargh! I found a shiny bit of plastic in the rear footwell, some examination shows it to be the remains of the bezel from around the seatback latch handle. How the heck did that get broken? I suspect my wife, who drove the car yesterday evening. She can be a bit ham-handed when she gets frustrated, even more so than myself, and that does machinery no favors. Can't repair it since it's not all there. It's a dealer item, assuming I can still get one. Crap. She claims to know nothing about it, I guess it's going to be one of the great mysteries of life.
I bought another for-sale sign for the side window today. Cheap at twice the price if it has any positive effect! I tuck it between the inner wipe strip and the glass, this will even work with the top off and the window down.
I also readjusted the trunk latch to make it operate better with the locking system. A washer under the latch plate at the bottom screw did wonders for relieving some rubbing that made the button stick sometimes.
I opened up the driver's door. (While doing this I found the missing piece of seatback latch bezel trapped in the seat belt mount, so I ought to be able to glue this back together.) With the door open I removed the vacuum valve. Putting the vacuum test rig on the locking line I found that it indeed does not leak. Next was the unlocking line, same thing. (I put on about 12" Hg which is what the football can make, then walk away for some time.) Next was the vacuum supply line, with it capped off in the engine compartment. (It's best to check for cracked lines before blaming the valve itself. The valve was new a few short years ago, and was a VDO from the dealer, not a no-name.) It didn't leak either. That meant it was the valve.
Now, I'm not adverse to buying a new valve, but this was a new valve and it really hadn't lasted that long. I was not impressed.
So, I checked my parts pile and found I had about five of these valves, procured from various junkers. I took one of the clapped-out ones that was loose and leaked very badly and opened it up. (They're not meant to be opened. I set the jaws of a vise at just the right opening so that the valve body wouldn't go through but the plunger and retaining washer could, then I used a nail as a punch through the vent hole on the other end to drive it apart with a small hammer. The retaining washer broke through the plastic lip at the end but that's no great loss. I think this washer just keeps the plunger from coming out during shipping and installation, once it's in place it's of no use.) With the valve apart I could see that it's just a smooth cylinder with three taps in it, and a plunger inside that has two rubber cup seals, one at each end. These cup seals were apparently a bit shrunken and no longer made a good seal against the cylinder. The rubber wasn't dead yet, though, as I proved when I removed them from the plunger. They have to stretch significantly but they didn't tear and there were no signs of cracking or other damage. So I grabbed my Harbor Freight O-ring assortment (SAE) and pawed through it looking for something useful. The second smallest ring, R02, seemed about right. With one of those rolled onto the plunger at each end outside the cup seals so that they wanted to nestle into the cups, forcing them outwards a bit, the valve then sealed very well. It slides fairly stiffly, but not so stiffly as to not operate. With the valve connected (but not fully installed) the system pumped down again with no perceptible signs of leakage, either locked or unlocked.
Since I had the door panel off I decided to glue back the bottom edge where the vinyl had come unstapled from the fiberboard in spots. It was catching on the sill and making a noise whenever you opened the door. I used weatherstrip cement and a bunch of small spring clamps. I also glued the seatback release handle bezel back together with gap-filling cyanoacrylate glue and pushed it back in place. I let the glues dry while I had breakfast.
The repaired vacuum valve worked well, but was stiffer than the original. Enough stiffer that the door keylock couldn't actuate it in both directions. (It could be adjusted to work either way, but not both ways at once.) There was flex in the linkage to the lock, and a bit of slop where that flat link is itself loose in the round mounting holes. The retaining clamp also didn't grip quite tightly enough. So what I did was to fabricate a mild steel bar as a link, and screwed it into the holes top and bottom with self-tapping screws. This eliminated the slop in the linkage. I also used some bicycle inner tube rubber to shim the clamp so it wouldn't let the (now stiffer) valve body shift. Unfortunately all this didn't help the problem, so I removed the door handle and latch assemblies to have a look. (That was actually quite difficult because the roll pin hinge of the door handle had worked half out and was trapping the whole assembly in the door. Once I finally got it out I tapped the pin back into place with a hammer.) The 'finger' on the key lock had worn some over the years and didn't shift the lock bar quite far enough anymore. I bent the ears of the lock bar inwards a bit to compensate for this and reassembled the door. (This whole procedure was much easier said than done. Figuring and fiddling took several hours.) That gave the lock bar just enough more travel that it could actuate the lock in both directions with the key. It's still kind of stiff, but it works correctly now. I then buttoned up the car.
The weather was magnificent, the car's thermometer read 72 °F and we had a nice scenic family drive around the newly paved road around the old lakebed, and stopped for lunch and ice cream. The lock system held vacuum for the hour or so we were stopped, so it's definitely better than it was. I'll consider it fixed unless I find out differently. Tomorrow morning if it's still holding enough vacuum to cycle the locks before I start the car I will know for sure.
No, the dome lights flaked out again when I got to work. I popped out the glove box liner and poked at the can containing the transistor circuit, and the lights came on. Obviously there's a loose connection in there somewhere to track down.
Rain today, so back on the hardtop goes.
...It does seem to work. Once or twice the speed sagged mysteriously on hills, but then it came back. Other times it behaved more like I'd expect. More testing is called for, there was no opportunity to try it on the freeway.
Got a call on the car. We'll see. He wants me to call him tomorrow, he might come look at it. Jill also has a friend that's examining it with interest, they had a little test drive today.
There is a small crack in one of the seat back covers, so I dug out the Leatherique crack filler. Unfortunately it had dried up, even though I'd put it inside a glass peach jar. I tried resurrecting a lump with ammonia (which I believe was one of its native solvents), but didn't have a lot of luck. I was unable to get it to mush up enough to take the paint. I puttied the crack anyway, and painted over it.
Jill drove the car today, and reports that Glenn's cruise control amplifier hunts too much, especially at higher speeds. OK, will look into that.
I called the prospective buyer at the appointed time. The guy offered some free web hosting for 2 years, and $6000 cash. Sold! He said he didn't need to see the car as he'd already looked it over when he took down the phone number. He's fulfilling a youthful promise to his mother, and plans to paint the car, Maaco. Perhaps red, perhaps silver. We'll make the transfer Monday, at the bank. Let's hope all goes well. I've got some work to do to scrape up all that goes with the car, and clean out all that does not. I also need to finish with Glenn's cruise control amplifier, and take another look at the door lock valve. I don't think Jill's going to have one last drive in it. Oh well. She got to drive it today, it was very nice out and I heard her blasting the tunes as she drove in the driveway.
I decided to adjust the door vacuum switch some more, I think I made it better. Certainly it operates easier now, it really had gotten too stiff.
I resoldered Glenn's cruise control amplifier in the area of the servoamplifier circuit, then took it in the car for a drive. It operated nearly perfectly this time. It even remembers the set speed while the car is turned off. I'll box it back up and send it back. I'm glad it responded to the repair attempt, tomorrow I'm going to lose my test bench!
After this I put the door and under-dash panels back together. She's ready to deliver.
Whew! That's a heap of worry off my plate. (Will it sell soon? Will something bad like accident or vandalization happen to it before we can sell it? Will something break because we're driving it so that it'll be seen as for sale? Will something happen to the car(s) I should be driving while they rot in storage? Etc.)
Curious about the effectiveness of my "advertising campaign", I'd asked him how/where he saw it; he said that his girlfriend had spotted it in the parking lot of the drugstore across the intersection. That's interesting, because this car was never over there! (I have seen other SL's parked over there for sale from time to time.) She'd also told him it was 'tan'. He drove by and saw it in our lot and told her, no, it's brown, not tan! Well, I guess I'm glad she saw some other for-sale SL that day, and that it wasn't around cluttering the field the day he came by to check it out.
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