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Mercedes 300D Suggestions



  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 58,496
    rocque--never heard that, sorry.

    Engine keeps running when key is taken out :

    There is a vacuum switch that shuts off fuel, and this is obviously bad on your car.

    Not a big deal.

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  • paul29paul29 Posts: 178
    If you have any hoses disconnected the engine will not shut down with the key vacuum switch , Just hook them back up and it should work , that is , if it was working before. The emergency lever on the engine can be used to shut it down if vacuum is lost.
  • anibalbanibalb Posts: 193
    I am amazed at the detail of your knowledge. I will do as you say and open the Module unit. I already disconnected it. I am not sure how to remove the circuit board. I had taken it all apart but was unable to remove the circuit board. I think I just gave up because I did not know what I was looking for. Now that I do I will look it over again before I buy a new one. They are expensive units and if a little fix will do it then I will try it.

    I am also debating whether it is worth getting the Mity Vac. Not sure that I need one. I can bleed brakes without one. Do you guys use it much? Please let me know. Also I believe in quality so I would not just buy the cheapest. Please let me know if it is worth it.
  • paul29paul29 Posts: 178
    Very good tool for these cars . Plastic and metal versions are available, the first one (plastic) that I had, cracked where the guage screws in, it was replaced two years later at no charge. If the metal one had been available , I would have opted for it.
  • burdawgburdawg Posts: 1,524
    I use my Mity Vac all the time, anibalb. It's very handy to have around. I do agree though to get the metal one. Much more durable.
  • anibalbanibalb Posts: 193

    Thanks. I will NOT get the plastic one. I don't believe in doing half (complete) jobs nor do I believe in cheap tools! Kind of an Oxymoron. I want to do a good job with cheap tools. Ha ha. I hope the manuals do show how to use the thing.

    Paul, In taking the ACC module apart, the board is hard to take out. I think I have to remove the levers that hold the buttons by removing the little c clip and spring. The casing around the board has an L shape.


    Button > (-- |_____Board_______| < back

    BOTTOM (Bottom case cover comes off)

    So the board doesn't just slide out. Looking above you have to pull it down and out. But as you pull down the board in the back the button levers crimp in the front against the top. There is not enough clearence to pull down and out. Question then is, when I pull button out, DO I have to also remove the spring and take out the white levers???? Hope you know exactly what I mean. Thanks a lot! I didn't want to force it out because I may damage the board even more!
  • paul29paul29 Posts: 178
    Cannot remember exactly how I disasembled the module ( a person should write this stuff down ), if it was difficult I would've remembered that. I know I had the buttons out and the board on my table and I used my fine tip soldering pencil and my bench mag glass, and in my case the two board circuit lines had actually discolored a bit at the OC points . Always keep in mind that this was assembled from pieces , so unless sealed in epoxy, it can be taken apart and you are correct , do not force anything except maybe to bend a cover tab or two. . I am looking at a picture of it, but not closeup so no help. Mr. Shiftright has a spare unit out of his dash, maybe he could look at it and offer a solution ( if his is the same model CCU ). I've always found the more eyes you have looking at a problem , the better the choice in solutions.
  • anibalbanibalb Posts: 193

    I took it all apart last night. And I did an overhaul of certain connections. I have to deal with the tools I have. I did not have a fine pencil soldering tool. But careful attention and precision allowed me to do it with regular soldering unit. It turned out cleaner that I thought originally. I reinforced all the connections on one side. The other side was still solid. However It should be all set. I will test it today!

    Gotta watch the World Cup at the same time. I also repaired my aftermarket radio. Someone had tried to pry it off and steal it from the previous owner breaking the casette deck. That is all fixed too! Thanks to CRAZY glue. I already ordered the Mity Vac. I also got a pair of used window motors and regulators. One of my regulators in back is bad. And I heard you cannot adjust the regulator.... Is this true?

    So this is all happening. Soon the benz will be in "PERFECT" order once again! Still amazed at how it doesn't drop any oil on the floor. Engine is in great shape!!!

    Paul, again many thanks!!!!!
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 58,496
    I think your car and my 300D are different in lots of small ways. I have noticed that in our conversation so I don't want to give you the wrong advice, especially with electrical connections!

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  • paul29paul29 Posts: 178
    Does not appear to be any adjustment on the regulator, in any info I have. As you are finding out it does not pay to take too much time to repair a part such as a regulator if it is relatively cheap and easy to get. Parts that get to the $50 and up range are certainly worth the effort. For instance the power rear glass regulator in my Toyota 4 Runner broke one of the nylon rollers which run in rails to lift and lower the rear glass. There are no used regulators available here as they all freese up with rust from the salt solution running down the glass. I lube mine regularly so the only part I needed was a roller. To get this you have to buy the whole thing new, about $175 . A trip to the hardware store and for $3 a nylon roller of the same dia was purchased , it was narrowed to the right width on a fine ginder wheel and with about 20min of work with a Dremal tool and it was ready to be snapped in place, that was two years ago, it worked and was worth the effort. Also I see a note in the Performance catalog saying you can order cruise control parts from them to substitute to find the defective part and if not the guilty part, it can be returned if in "as sent condition" for full refund. They can tell you which parts to try first. I bought quite a no. of parts when they were called Impco and located in Texas, they are knowledgeable on Mercs
  • anibalbanibalb Posts: 193
    I agree with you and the time effort/value ratio. It is more of the hobby thing that makes me enjoy the repairing part! I enjoyed fixing the ACC module. Also that piece is a little more expensive.

    On the performance catalog, do you mean I hadn't known of that. Maybe I will fix the Cruise Control. I will not use it much and I know that. But I like to know that everything works like it should!

    After sitting for a few days, when I opened the door, the others did not open. So I know that I have a leak somewhere. The Mity Vac should be on the way as well as the manual CD's. The best thing is that I am having fun with it.

    Oh! it seems to leak some oil through the oil filler cap! And in the last service record it said that the oil filler cap seal was replaced. So what should I do???

    Thanks for all the info!
  • paul29paul29 Posts: 178
    Try , They have the oil filler caps for about $3. The car may have been aftermarket undercoated , if a product such as Ziebart ( diesel fuel based ) was used , any rubber parts will deteriate over time, from the vapors. The doors ( except the drivers ) , trunk and fuel flap are lock/unlocked by vaccuum motors which have rubber diaphrams. I did get just the diaphrams ( rubbers ) at one time , but don't recall the source. Some else reading this may be able to help. The diaphram kits ( just the rubbers ) were about $5 , the whole push/pull motor is about $22 to $30 aftermarket.
  • rocquerocque Posts: 37
    Hi Mr. Shiftright, I have three questions for you.

    1. What do they do when they rebuild the engine in the 300D and how much will it cost(cnd dollar)
    2. Does that mean the engine will be like new
    3. What is the difference between the 300D and the 300SD
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 58,496
    300SD is turbocharged.

    you don't want to know the cost of rebuilding a 300D engine and you don't even want to do it, because you can buy about three nice 300Ds for the price of the rebuild and keep two as spares.

    Other alternatives would be a junkyard engine.

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  • mod62mod62 Posts: 38
    What would be a good price for the above car with 300,000 miles. The guy wants $2,500.

    Is it worth it. One owner
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 58,496
    No, it's not worth it unless it is all rebuilt. About half that amount would be fair, unless perhaps he has receipts for a new engine and transmission. Otherwise the car is basically worn out and every mile could be the last.

    Give you a for instance, mine is a high mileage car 230K, ( a 1980 W123 chassis, very similar to this car) and I just priced new CV joints (axles) for the independent IRS, and new they are $600 each, $225 each rebuilt---+ 4-5 hours shop time. (I found some good used ones at $115 each and I'll put them in myself---a long day's work for me on the ground).

    Maybe the diesel engines are long lived, but those engines are also dragging around an entire car with 300K on all the components. Buyer beware!

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  • rocquerocque Posts: 37
    Hi Mr. Shirtright,
    I'm from Canada and just to let you know what our winters do to nice cars..........(IT EATS THEM FROM THE INSIDE OUT!!!!!!)I was wondering.
    I was just on ebay, and I saw so many nice looking w123 mercedes benz diesels. My question is, are cars from the States(nice whether areas)better to buy, would you recommend buying a car on Ebay...
  • jrct9454jrct9454 Posts: 2,363
    ...and read everything from the beginning. I'm a long-time MB nut, have owned a grand total of 13 of them on and off since 1968, but never ran one out of warranty. [I've also been an MBCA member most of the time since 1973, and an an avid reader of the tech advice in the STAR, but up to now only as an interested spectator].

    So here's the question, for our host and anyone who want to chime in:

    I'm looking for an MB that we can use reliably for longer trips, but where total annual miles probably won't exceed an average of around 6000 or so. We have a nice reliable late-model Corolla for the local runaround stuff. Because I'm not a mechanic, I haven't bothered with looking for anything but low-mileage cars. For the past 2 issues of the STAR, there is a guy in SoCal who is trying to sell an '81 300SD [more or less identical to a car I once bought new] with less than 10,000 miles on it since new [no, not a typo]. He wants $20,000. Yeah, I know...but the questions are these:

    -What is this car's value, do you suppose, in the cold hard real world?

    -What should I be looking for in inspecting the car, beyond the obvious [starting and running like a car with only 10k on the clock, AC function, no obvious leaks, running vibration-free at freeway speeds, etc.]? Yes, I'd probably take it to a professional, but only if it passes my cursory examination on the driveway and the road - here's where I can use some hints.

    -How should a garage queen like this have been maintained? At least annual oil changes for the engine, but how about other fluids?

    -Should I be worried about other rubber parts besides tires [which I would replace in almost any case - I have strong prejudices here]? Seals, suspension bushings, door/trunk rubber?

    -Joe has already given me some ideas about maintenance costs; anybody else is welcome to chime in.

    I owned a total of 5 diesels during the 70's and 80's. My experience was that the turbos were far and away the most enjoyable cars to drive, and always seemed to run better on the crappy diesel fuel we have in this country than the normally aspirated engines. Still, I'd welcome any "watch-out-fors" from any source - I'm an MB veteran, but not in the area of cars with 20+ years behind them.

    Finally, a question for Joe: are you the "Troise" half of the R&T cartoon team? If so, I'm a big fan....

    Thanks in advance for everyone's input.

    John R.
    Elk Grove CA [near Sacto] working AC is an absolute necessity...
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 58,496
    Okay, John R got his question addressed in another topic, so that leaves ROCQUE.

    Buying a Car on Ebay?

    Ah, I'm really divided about that. I suppose it depends entirely on the published reputation (feedback data provided by Ebay). I've seen a Florida dealer for instance, who gets very good feedback on his sales, so he must be doing something right. HOWEVER, that doesn't mean his clients don't find some problems later on, after the honeymoon.

    Personally, I would buy a car on Ebay but only after having hired someone to look at it and report back to me.

    As for a 300D, e-mail me rocque and I may be able to turn you onto a good W123 sometime.

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  • rocquerocque Posts: 37
    Thank-you for all the great adive you've given me over the months.
  • rocquerocque Posts: 37
    Hi Shifty, I went to look at a 1982 300sd with 324km on it. The body was o.k with just a few little spots of rust it. It started right away,but idled a bit rough(THE SALES PERSON SAID, DON'T WORRY THE CAR IS 20 YEARS OLD....WHAT EVER) anyway, what the deal on the climate matter what button I pushed, nothing happened.......even though I could here the fan working I think...The guy told me that it was cheap to get fixed, what am I really looking he's asking 6500$ cnd
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 58,496
    Hmmm.....roughness could be something simple, like the two fuel filters (large one and the pre-filter) or it could need a new set of glow plugs (about $60 + 1.5 hours labor).

    As for the climate control, there is a bit of a delay but it should kick in after a short time.

    You tell him "if it's so cheap to fix, why don't you do it and I'll pay for it before I buy the car".

    I'm sorry to be so much is $6,500 cdn?

    If you really like the car, ask the dealer to change the filters and/or glow plugs and get the climate control working.

    WARNING: Rough idle on a 300D could also mean low compression in one cylinder!
    On a diesel, given the high compression ratios, any drop, even in one cylinder, ha a pretty strong effect on idlling.

    People never adjust the valves on these engines like they should, so you could also have a tight valve.

    So tell the dealer to square the car away.

    Any 300D should start instantly and idle smoothly within 5-10 seconds.

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  • rocquerocque Posts: 37
    Shifty I saw a nice 1992 mercedes sd. Are they as good as the older ones(quality stand point)
  • capbillcapbill Posts: 1
    I have been enamored with the oft touted great engineering of the MB autos but am baffled when I read on these boards about owners having to replace their engines on 300's after only 100,000 miles. I am seriously considering getting a 1992 300 but am concerned after reading these postings. I presently have a 1985 Buick Sabre with 255,346 miles and other than brakes, tires and batteries, have only had to replace the catalytic converter and had a minor transmission repair since the auto was new. Am I being stupid to think that any used, well cared for, Mercedes I purchase will do as well?
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 58,496
    Don't believe everything you read on the Internet and even if you can believe it remember that it is anecdotal evidence which gives no clue as to owner maintenance (or neglect), previous history of the car, etc.

    I'd estimate about 95 out of 100 people complaining about Mercedes quality have never owned one, and of the 5 who have owned them and had bad experiences we often don't know the complete circumstances.

    Certainly, every now and then any car made will cough up a few poor examples, but given the quality that goes into a Benz engine I'd say that a failure at 100K would be far more the exception rather than the rule.

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  • mbdrivermbdriver Posts: 426
    capbill - As our host pointed out, there are exceptions with each auto nameplate, and I'd say your Buick with 255,000+ miles and minor upkeep expense was an extreme exception! My own experience differs dramatically -- by far, the worst build quality car I ever owned was a Buick Super (many years ago).

    Mercedes diesels are probably in a class by themselves when quality and longevity are considered. The thousands of Mercedes diesel taxis in Germany speak well for their quality and endurance. My wife has a 1977 300D with 97,000 miles, and she's fond of saying that it's almost broken in! But then, I ensure that it's properly maintained, and it's garaged whenever it's not on the road. When we drive it and stop, people keep trying to buy it from us!

    Bottom line -- if a Mercedes diesel is given proper care and regular maintenance, it should last a very long time and accumulate many miles.
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 58,496
    Seems to me that any claim proporting that an entire product line of a distinguished automaker is deteriorating rapidly in quality would have to be supported by some rather substantial, timely and thorough evidence.

    If it isn't supported by such, one would have to suspect malicious intent.

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  • mbdrivermbdriver Posts: 426
    If your Post # 148 regarding a claim that an entire product line of a distinguished automaker is deteriorating rapidly in quality was aimed at my comments about Buick, I suggest that you read my post again. There was no such claim, and there was certainly no malicious intent. The Buick I reported about was a horror story on wheels, and whatever could go wrong, DID. That was decades ago, and as a result, I've never owned another Buick.

    I'm reasonably sure that my experience has been repeated by owners of every make of automobile that's ever been on the road. And I would say AGAIN that ANY car that is driven 255,000+ miles with minor upkeep expense is, indeed, an extreme exception (Mercedes diesels included -- they DO need regular maintenance and frequent upkeep that often is costly). I believe you're aware that in Germany, Daimler Benz awards 100,000 Km. grill badges to owners of Mercedes diesels as they accumulate each 100,000 Km., and some grills sport four or more such badges!
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 58,496
    No, no, no such intent whatsoever.....didn't even cross my mind. Sorry for the misunderstanding if that's what it looked like.

    It was just a general comment about brand-bashing.

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  • mbdrivermbdriver Posts: 426
    Glad I wasn't the target or focal point. Maybe I'm just getting more sensitive in my old age.

    In any case, I think consumers ultimately decide which brand of autos survive and which bite the dust. I remember Nash, Studebaker, DeSoto and more recently, Plymouth. Soon Olds will join the list. For a while, Audi was on the ropes, at least in the U.S. market. Some would say, "Too bad." Others might say it was bound to happen. My bet, though, is that we'll never see Mercedes or BMW discontinued.
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