Mrs. Coast's New Ride
 

This is going to be a long post, I'm afraid, but hopefully a good story will be the result. Mrs. Coast has driven her somewhat ugly but reliable '83 240D with manual transmission as a commuter for several years now, but a chronic knee problem has lately caused her to favor the '72 coupe with automatic transmission for daily driving. The coupe is beautiful, much more fun to drive, and always was her true love. Sadly, the fuel economy from a 250C is horrendous, and the High School parking lot where she must leave the car all day is not a safe place for a well loved classic with a perfect body. So we recently embarked upon the quest to find a decent (but not too nice) diesel for her every day use.

After some searching, it boiled down to a choice between a non-turbo 2.5 190D (with a sad interior and very bad steering and brakes) and a clean '84 300D (with recent major brake work, a new front end, an AC that blows cold, and a host of other problems). Since neither of us cares much for the tighter quarters of the W201, a low-ball offer was tendered on the 300D and promptly accepted. So now I have the pleasure of bringing back another neglected 300D to respectability. At 290K, it still looks and feels pretty good.

At the starting point: some off the line hesitation, a little smoke, a big enough vacuum leak to make the brake pedal pretty hard and cause semi-functioning door and fuel door locks, a little trouble with the 3-4 shift, and an oily mess under the hood. A really scary looking Lovecraft type setup gave some pause, but the PO was clearly not the type to be messing with grease. He confirmed that he'd never run VO. He thought he'd need the "conversion" to run biodiesel, and evidently some sleaze ball who is probably now in jail was happy to take his $700 to install this useless equipment.

First order of business was to give the engine compartment a good pressure washing, followed up by a good scrub down with strong caustic cleaner and a thorough rinse. After a good cleaning, I can confirm that there is indeed an engine under the hood, and everything looks to be hooked up. Next up: yanking out the Lovecraft type junk and restoration of the fuel system to the original configuration. Nothing but diesel fuel in the big glass water separator filter. That's a relief. PO's records indicated that the last valve adjustment was performed at 270K, so might as well go there next. All valves were tight, but not too bad. Chain rail looks OK, and chain checks out good enough to leave it for now. Hot or cold, there is not enough blowby to make the cap move at all, and there is zero engine rock. Oil pressure went to 2 bar at idle after a 50 mile run. The oil cooler hoses are a year old and genuine MB.

So far I'm liking what I see, except for that smoke and hesitation. So out come the injectors. At that point, a compression test seems like a good idea. Results are encouraging, with readings between 420 and 430 in all of the holes. The injectors look like the originals to me, though that turns out to be not exactly the case. Several days later, Mark (aka Greazzer in these pages) informs me, in gentlemanly terms, that they are among the worst he has seen. I receive the rebuilds several days after that. I'm not even sure that these are the same injector bodies, but they sure look good. (For anyone that needs injector service, it would be a mistake not to send them to this guy. He is prompt, communicative, and very reasonable. He's one of that disappearing breed of craftsmen that maintains standards and will do whatever it takes to get the job done right.)

In the down time, I've found a bad vacuum actuator behind the heater box, and a couple of other leaky ones in impossible places. These are going to be a challenge to sort out without taking out the dash. Fuel door actuator is toast. With the green vacuum line for the ACC system isolated and a couple of tees plugging off the fuel door lines, the vacuum reservoir holds well, and the door locks will cycle a half dozen times on the reserve. I'd rather have had a couple of bad door locks, but that's the way it goes sometimes.

Today I found time to install the newly rebuilt injectors, The engine fired up while I was still bleeding hard lines. I clumsily managed to snap the plastic tee off the brake booster line, so now I have something to spend the PNP credit that's been in my wallet for six months on. Between the new injectors and dealing with a few worn linkage parts, the hesitation off idle is virtually gone and the pedal feels a lot better. Still a little smoke at the tailpipe, and I noticed that some air is showing up in the line between the lift pump and the fuel filter stand, so there's more to be done there.

I'll change the transmission filter and fluid next week, and then investigate the vacuum modulator situation. Shifts are smooth, maybe a little late. The biggest concern is a downshift from 4 to 3 when I let off the pedal. This will be a bigger concern if it still occurs after I'm satisfied that everything is right in the fuel delivery department.

I suppose that we will end up with a little more into this car than we would have if I'd just picked up one of the plentiful old Volvo's that can be found on every block in Portland. That would have been the farthest that the Mrs. would have gone as a compromise, and she would not have been happy. She is the real MB enthusiast in the family, and she doesn't want to drive anything but a W115 or a W123. I've long understood that my function in life is to give her whatever her heart desires.;) I'll post more as this project progresses, which will happen as time allows over the coming weeks.

I did the same thing with my brake booster line not too long ago. New replacement from this site was only about thirty bucks. May as well buy new like I did and not take chances with an aged and brittle PNP replacement.

Condolences about the knee problem. If that happened to me it might get me looking at flappy paddle gearboxes.

If you got a girl to drive a Mercedes 83 240D STICK-shift and not say "eww it's old and it stinks and sometimes smokes!" then you know you hit the jack pot and she's a keeper! :D but question, if she has knee problems what difference would it be switching from a 83 240D to an 84 300D? Just curious! Also, the vacuum modulator control how HARD it shifts. If they are smooth I'd think it's something else. The Bowden Cable controls how late it shifts. That's more where I'd look!

Knee problem = pain while working the clutch

I knew that she's a keeper 35 years ago:). I'm 6'2", and with my size 14's I can work the clutch without lifting my foot off the floor. The lady is only 5'5" and she barely reaches the pedal. It's the cumulative effect of constant shifting in city traffic that seems to be aggravating the problem.

I agree with the bowden cable principle, but my experience with these cars tells me that tweaking transmission inputs is futile unless the fuel and vacuum systems are functioning properly. What I perceive as slight late shifting may have more to do with sloppy accelerator linkage and weak fuel delivery. I'm just just going to verify vacuum and modulator pressure for now, and get some miles on the car.

Wow sounds like the story of my life....I first had a euro 300d was my daily even though I had a dart but the dart is like the 250...consider yourself lucky to get 12mpg.....so I used the 300d as a daily.....well my knee became three times the size of my right knee....assuming I was going to have surgery I sought out a auto....my current car....well come to find out I have a rare forum of arthritis...yeah me....it has taken out my knee and I am to young for a totally replacement.....I miss my euro....the stick was fun, just not in traffic.....though I have come to really really love my auto now that the kickdown is fully functional, linkages adjust and all the tranny bugs worked out.....

Your story of resurrection is so common in the world of diesel Benz.....all of mine have been exactly the same way.....oh and his dare you not include photos in your story :D air in the fuel line is most likely the primer pump, I would recommend rebuilding or replacing the lift pump too....one less thing to worry about later on...

The new brake booster hose arrived today. Threads on the nut at the booster end had a bit of metal shaving firmly stuck in them. Typical of the quality of Genuine Mercedes parts these days. They cleaned up OK and the hose went on without much trouble, but the outcome would have been quite different if I had not first checked.

The smoking and lack of power off idle appear to be symptoms of a fuel flow problem, probably the tank screen and a fuel line leak at the tank. The hesitation disappeared, along with the air bubbles showing in the clear lines, after the fuel lines were temporarily reversed. Still a touch of grey smoke from unburned fuel, but that could be from the B99 in the tank. The new Monark injector nozzles have also quieted considerably now that they are getting better fuel flow.

Now that the vacuum system is closed up and fuel delivery is at least adequate, the car is ready for a good drive to see if transmission response is improved. Since the tank is full, the tank screen inspection and fuel pressure tests will have to wait. It will be at least another week before the tanks on the '79 are depleted enough to take the 20 odd gallons that need to be emptied. The electric fuel pump that was a component of the removed "biodiesel conversion" is still working, and it will help greatly with the fuel transfer. Time do do a little cleaning on the interior, and figure out how to replace the antenna (or just the mast?).

When you get the car all cleaned up will you be proudly posting pictures of it?

I imagine that I'll eventually put some pics up, but a plain vanilla 300D in average shape for its age is not something that readers here haven't seen before. At some point I will provide an accounting of expense and labor time as well.

doesn't matter
 

pics!