Howdy, Stranger!

It looks like you're new here. If you want to get involved, click one of these buttons!





If you experience loading issues with the login/register form, please completely disable ad blocker or use an incognito or in-private window to log in.

Mercedes 300D Suggestions

1616264666777

Comments

  • burdawgburdawg Posts: 1,524
    The only way I would ever consider trying to repair this engine would be a complete disassembly & inspection. Thanks for the photo, it answered my question about the cam towers.
  • Does anyone know what years will interchange with a front seat for an '82 300SD (126)? I bought one from a junkyard recently, it came out of an '83 126 but it's not bolting up easily. My old one has a nice angle on the rails at the front where it bolts to the floor, where the replacement seat's rails are very straight. Do I bend them and make them work, or should I try to swap out the whole mechanical assembly?
    Thanks for the help!
  • lwoolardlwoolard Posts: 38
    HI all, I just purchased a 1979 300sd for $800.00 with 249000 miles on it. There is one issue with the car that I could use some help with. The brake booster, door locks, climate control, and engine shut off, which all work on vacuum do not work. Also the transmission will not shift at low rpms. After driving the car for a few miles, everything work beautifully except the trans shifting. I took the brake booster line off at the vacuum pump and noticed the pump is pulling a little vacuum and it increased as the engine rpms where increased. I don't have a vacuum tester. I was wondering where my problem might be. Does the transmission shift on vacuum or is this another issue. Is there a vacuum module on this model, if so where is it? Also when I cut the key off and rev the engine it will shut off.
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 61,732
    You either have a bad vacuum pump or lots of vacuum leaks. All your problems are related to vacuum loss, including shifting. Diesel engines use vacuum pumps because they produce very little manifold vacuum, as they don't generally use throttle butterfly plates. Your vacuum pump should be putting out I think around 20 inches of vacuum after one minute of start up.

    MODERATOR --Need help with anything? Click on my name!

    Share Your Vehicle Reviews Here

  • ghoffmanghoffman Posts: 3
    Dawg! You ware right it was bushings, But in 200,000 mi I will be ready! squeaks are gone. thanks
  • lwoolardlwoolard Posts: 38
    Thanks, I was thinking the vacuum pump was bad. I see they sell rebuild kits online. Is that the way to go or do I need a new or remanufactored one. Is there a way to tell? I checked all the vacuum lines that i could find and all seemed to be ok. Is there a valve on the tranny that could be bad?
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 61,732
    I haven't been under one of those old babies in a while but I think there is a vacuum modulator for the transmission, yes. Where it is exactly I don't recall. But sure, any vacuum line dangling off or cracked can screw up everything. Sure you can rebuild the vacuum pump---it's not a 100% success rate but I shudder to think what a new one costs.

    MODERATOR --Need help with anything? Click on my name!

    Share Your Vehicle Reviews Here

  • brakeengrbrakeengr Posts: 98
    I had my vacuum pump rebuilt with much success- solved a lot of the vacuum related problems; and inexpensive!
  • lwoolardlwoolard Posts: 38
    Ok I pulled the top off the vacuum pump and found the diafram was cracked in 3 places. Bought a new diafram and the pump works great. I got my locks, climate control, brake booster, engine shut-off all back and they work surprisingly well given the age of the car. Cost $40.00 that's the good news. Here's the bad. The transmission will only shift a high rpm's from 1st to 2nd at 20 mph, 2nd to 3rd, 45 mph, 3rd to 4th 62 mph. Then when you slow down to 53 mph it down shifts back to 3rd. I unhooked the kickdown under the gas pedal and still no difference. I have examined all the vac lines and all look good. Does anyone have any suggestions? I looked at the tranny fluid and it is not brown or burnt smelling, it's red and fresh looking.
  • have you had a close look at the little plastic valve with three vacuum pipes, on top of the rocker cover, next to (and operated by) part of the accelerator mechanism. It may be leaking and would cause the gear shifting symptoms described. While waiting for a part I took a deep breath (as noone could tell me if it was wise) and removed it, temporarily sealed the pipes, the outcome was gear changes at low revs.
  • lwoolardlwoolard Posts: 38
    Thanks for the reply but this model doesn't have that on the rocker cover, My 1983 300D has it but this on doesnt. There is a metal rod connected to the rocker cover and i adjusted that in and then out and nothing. Any help is greatly appreciated. :)
  • lwoolardlwoolard Posts: 38
    Ok, I check the vacuum lines and all look good. I did notice today however that when I press the brakes the tranny will shift sooner. Does this indicate a vacuum problem? If so where?!?
    Its a 1979 300sd.
  • lwoolardlwoolard Posts: 38
    Hi, I have traced a vacuum leak in my 1979 300sd. I will try to describe as best I can. It is located to the right of the injection pump and above the shut-off valve. There is a vacuum line coming into it and another line coming off of it to the valve that is connected to the firewall. It is cream colored and is hooked to a lever that is coming from the bottom of the engine. I think it has something to do with the transmission vacuum. Does anyone know what the name of this part is so I can order one. Also does anyone know what it does?
  • In a reply to a post you suggested the following. "you might also consider thinning out your fuel with kerosene, and getting the biggest, baddest a** battery you can find. And additives. And starting ether." How much kerosene per tank? Where do you apply the ether?

    Thanks.
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 61,732
    Depends how much diesel fuel is in the tank. If it's full up, a gallon of kero wouldn't hurt I don't think. The ether (don't use more than a couple squirts, one or two times ONLY, then quit) just goes into the air filter, or even through it if you wish.

    Ether is a solvent, so make sure you don't "wash" your cylinder walls with an excess amount---if ether doesn't kick it over pretty quick, you have other problems.

    MODERATOR --Need help with anything? Click on my name!

    Share Your Vehicle Reviews Here

  • link title

    I've read several posts and it seems there's a vast disagreement on these cars starting in first. Some say every car they ever owned did, others say that the car was not designed that way.

    My 4 speed transmission only gates down to 2nd gear, recently after service (oil, fuel filter, and drive line isolater bushing) the car started starting in 2nd gear. Prior to that it mostly started in 1st and only spurratically started in second.

    I don't see a way to force it to start from first and mashing the gas doesn't seem to do it either. Vacuum all seems good and other than this the car runs excellent, it has 205,000 miles and we run it 100 miles a day as a carpool.
  • nigel6nigel6 Posts: 16
    I have an 1985 CDT , the AC doesn't seem to work. How do I go about testing various parts to figure out whats not right? How do I check If there is gas ? Does the system have a temp sensor to check ambient temp ? Does the compressor have a clutch and could it be stuck ? Could the problem be with the push button switch ? Can you bypass anything to test something ???? Any suggestions would be appreciated, Thanks
  • brillanzebrillanze Posts: 20
    Has it ever worked?
    Just go have a pro check it out. A/C on the old Mercedes was never good to begin with. If it is blowing hot air, you might just need freon. You probably at least need a conversion kit to the R-134 freon. If the compressor is shot, you also need a new drier. Major bucks--$1000.00 if you buy your own parts at a discount. Good luck!
  • nigel6nigel6 Posts: 16
    Thanks for the advice. Yes the previous owner said it worked and I have the bills for a new compressor, drier ,switch ? hoses, conversion to r134 and more. It does blow warm air ? If it just needs gas does that mean it has leaked out ? It was stood for some time ? Could the push button switches on the console be faulty ? Thanks.
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 61,732
    First thing you have to do is evacuate the system, test for leaks. If the gas is too low, the compressor may not engage. Maybe you'll get lucky and just need a recharge. If the compressor is seized, you can stop there, it will be too expensive to fix the system because metallic debris has polluted all the components.

    Even at its best, the AC on these cars is rather lame and you will have to recharge it once a year. But I got mine to work passably well in hot weather, once I got rolling down the road. On a hot day in traffic at 90 degrees, you can just forget it.

    MODERATOR --Need help with anything? Click on my name!

    Share Your Vehicle Reviews Here

  • from Alain I the oil is leaking from piston in transmission in rear mechanic says
    he got to reseal it , can you tell me if and how will he do the resealing of it and what is the time to fix the job or the amount it will cost to change the parts
  • also from the leak the oil is dripping since i bought the car last year
    so it is loosing oil but the mechanic says the piston sels have to be changed
    is it an easy job ex: how many hours of labours to fix
    he says from 500 dollars to up to 1000 dollars
    what do you think
    anyone knows [email protected]
    thanks
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 61,732
    Not sure what you mean by this. Is he talking about some seal inside the transmission? Perhaps in the valve body? If he has to take the transmission out and disassemble it, well fine, $1000 sounds pretty good--but once you have a transmission apart, it really makes sense to rebuild it. If he means just the valve body, you don't have to drop the transmission for that, so $1000 seems too high.

    MODERATOR --Need help with anything? Click on my name!

    Share Your Vehicle Reviews Here

  • nigel6nigel6 Posts: 16
  • nigel6nigel6 Posts: 16
    I have an 1985 300 and the car wanders on the road. I have put 4 new tires on recently but the car hasn't had tracking checked.Could it be the control arms? How can I check them for signs of wear.Hate to buy stuff if not needed. Thinking back the old tires were worn more on the inside edges on both front wheels ?Also I hear a clunk when I go over a bump at low speed, its probably there at high speed I just don't hear it. Is changing out the control arms straight forward ? Any suggestions as to the best place to buy them if needed ? Thanks in advance
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 61,732
    Control arms aren't the first place I'd look. Worn tie rods, steering arms, etc. The rear tire wear is probably the hydro-pnuematic compensator being tired, giving the wheels excessive camber.

    MODERATOR --Need help with anything? Click on my name!

    Share Your Vehicle Reviews Here

  • ewvdtewvdt Posts: 14
    Check the steering box for proper adjustment so there is no excessive play.
  • also the transmission makes a kind of knocking sound when moving to a certain speed and the oil is leaking
    i have to add oil my email
    [email protected]
  • how much woul be a motor turbo and transmission for 5 cylindre for merced 300 sd can anyone tell me
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 61,732
    You mean used or rebuilt?

    MODERATOR --Need help with anything? Click on my name!

    Share Your Vehicle Reviews Here

Sign In or Register to comment.