Mercedes 300D Suggestions

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Comments

  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    If you've had a turbo diesel, I don't think you'd be happy with a 300D non-turbo. They really are pokey and noiser than the turbo and 75 mph is a long way away (bring a magazine to read).

    You shouldn't pay any premium for a coupe body really because the price is determined by supply and demand and if anything people seem to prefer the sedan. The very idea of coupe and diesel is pretty strange if you think about it.

    If someone is trying to foist a coupe on you as being "rare" you can reply "Shiftright says that to be valuable, it not only has to be rare, but someone has to care".
  • los1950los1950 Member Posts: 2
    Thanks

    the coupe is beautiful without a b-pillar.
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    Yes some people like them a lot. I find the design a bit awkward on that big chassis. Mercedes coupes styled off 4 doors have always struggled for recognition since way back in the 60s. They fare quite poorly at collectible car auctions for instance. The coupe style is not Mercedes forte in the large chassis cars, but they do a very nice job on the SLs. "Short" seems to work for them better IMO.
  • drummer_ddrummer_d Member Posts: 4
    my car just got through with one shop, and they said my a/c has a vacuum leak. they said it would take a long time to find it and probably cost alot. so i was wondering if you had any suggestions, such as if it would be easier to just buy new parts, or thats not such a good idea because theres alot of parts it could be. also, i still have this water leak that comes up around the wiring in the backseat left side footpan. i think the best possibilities are the rear windshield and the taillight. but the place said they tried and tried but got nothing. from what i hear, mercedes put a rinky-dink a/c on this car (300d,btw), so is there anything i can do to make it better or am i just stuck with it? i had it converted to r-134 already. thanks
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    Yeah, Mercedes AC is pretty pathetic in the 1980s. I'm not sure what the shop means by "a vacuum leak" ??? If they mean some of the controllers in the climate control, yeah, that could be a problem. But if the AC system itself is leaking, I don't see why they can't find and fix that.

    I also think running R134 in an old Benz isn't a great idea. The AC is bad enough with R-12 and R134 just further diminishes it.

    I got my 300D AC to work pretty well, but I had to recharge it every 6 months and really keep on top of it.

    If you have the AC compressor that sits on top of the engine, those are really bad.

    But still, if you have a working compressor and you're full of freon, I wonder what the problem really is here?
  • drummer_ddrummer_d Member Posts: 4
    the problem is with the climate control, because the defroster works and it shoots cold air until i start moving, then it starts heating. but the rest of the buttons just dont do anything at all. (they did when i first got it, however.) its a '79 model, btw. and i dunno what they did to switch to r-134, so would it be probable to switch back? the main thing is i dunno where to get the stuff. my compressor broke while they were changing to the r-134, so they didnt charge for it. so any ways i got me a new one. i also had to replace the suction hose. lol ive spent more on the a/c than i have the whole car. (got it for $1000 w/ 135k miles, good thing is it was well taken care of, so the engine itself runs great. it still has the original motor mounts which i hear dont last long cuz my grandpa had a 240d a while back) so for a 26 yr old car that has only a/c problems and a water leak, i think its been good.
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    Well the climate controls on these cars generally sucked along with the AC system, so you have to decide how much money you want to throw at it. The parts are certainly available but first off you need a very keen, good, diagnosis of which components is failing. If it's just a vacuum leak and not a total component failure (the valves that control heating are ridiculously complex on these cars) , then maybe you'd get lucky with just replacing a leaking vacuum line. Of course, you have to find where that is....usually though a bad vacuum leak subverts the entire vacuum system in the car, meaning that your door locks won't work and you can't shut the engine off.

    This is a good parts and advice source: www.mercedesshop.com

    Also I used to get good used parts on eBay. I fixed up my entire AC system with used parts and it worked, but it was an uphill climb.
  • 300d300d Member Posts: 6
    Hi,

    I have a 1985 300D and the interior is pretty busted up. I went to a junk yard yesterday and saw a 1980 280 that has very similar door panels and seat. Do think if i were to put these in my 300D they would fit correctly? I really have about a million more questions but I'll just leave it with this one for today.
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    Hard to say. Best thing is to pop one of yours off and take it with you to the wrecking yard....or buy one with the understanding that you can bring it back....or try to match it up in the junkyard parking lot. If the 280 is a W123 chassis you might get lucky.

    Taking off Door Panels

    1. Remove large phillips screws from arm rest
    2. Pry black plastic plate away from inner door handle, and remove screw behind it
    3. Unscrew door lock knob
    4. Carefully pry off door panel and try not to break the snaps
    5. Remove chrome plate at door lock (maybe switch #4 and #5 here)
    6. Lift UP with panel and it'll pop off--straight up---don't BEND it.

    CAUTION: If you tear the plastic moisture barrier behind the panel be sure to repair it!

    If you break too many clips you can buy these at the Benz dealer.
  • jlusijlusi Member Posts: 3
    Thanks for all your speculation out there regarding the rap phenomenon on my 300d. I hate to dissapoint anyone but the noise is definitively at least by ear is not coming from anywhere near the engine. The mounts are good and there is no noise with the engine itself. Mr shift right first suggested rear cv joints. This is the best speculation so far. I crawled under the hood for inspection of the rear axles where it ties in....Im not a super mechanic familiar with all the right terms...But there is play in that axle....both axles I can move back and forth between the rear end and the wheels. I think this is normal. But I do think this could be a possibility. The noise is very elusive as it is disturbing....It is very loud at deceleration around 40 to 30 but there seems to be some play some where to cause intermintent crunching sounds in the same place as the more intimidating rap rap rap as if there were a gigantic playing card in the spokes, ...if it had spokes. The question is if rear cv joints or axles are at fault how could I test them beyond my grab them and shake them approach, How can I test them?
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    You cant' really test them. You have to take them down, take them apart, clean them and examine them for wear.

    You could try and "load" the CV joints by making very hard right or left turns at high speed, like a sweeping turn on the freeway or on a curvy road. If you turn hard left and you hear a noise, it's the right one, and vice-versa.

    They are pretty pricey items and I think there are two different kinds so you have to know which ones you have. Replacing both sides is probably around a $500 job if a shop does it for you.

    By all means also check the driveshaft bushings and u-joints.
  • biledieselbilediesel Member Posts: 2
    I have a 1979 300td, the engine revs high when the car starts off in 1st gear. When you let off slightly the car will shift but it skips 2nd and goes right to 3rd. When I start off in drive (1st gear) , rev the car appropriately then shift to (L) the car will shift to 2nd no problem, then just continue manually shifting up. The trans is the model before the vacuum modulated one and i'm not sure if an adjustment is possible. any help is appreciated.
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    I think they are adjustable by cable but you had better get the factory manual and not just start turning nuts here and there.

    These trannies are pretty hard shifting and kinda ornery but you should be able to get them to work a little better. I think your problem is at the throttle adjustment. There is a whole elaborate very German procedure for this and I doubt any living person remembers how, but maybe those factory manuals would be a good investment for you. It's a set of 3 I believe, and costs maybe $200 or so. Sometimes you see them on eBay.

    Also, check these guys for advice:

    www.mercedesshop.com
  • biledieselbilediesel Member Posts: 2
    thank you for your help
  • burdawgburdawg Member Posts: 1,524
    Jlusi: It's probably good news for you that the noise your hearing is from the rear and not from the engine bay. Anyway, on the side you suspect is bad, are the cv joint boots cracked open?

    drummer_d: The climate control servo is very likely the problem. You can troubleshoot it without the factory tools and manual, but you have to know what your doing. When you switch to defrost, the normal controls are bypassed and the fan goes on full. If the servo is working the heat goes to high level, and the a/c compressor is turned on to dry the air.

    I didn't seem to have a whole lot of trouble keeping the climate control working on my old 1980 280se, but it was expensive. I had the luxury of having all factory manuals, which helps a lot. The climate control on these cars is complex (probably needlessly so) and can be hard to maintain in an older car.

    I took the 280 to my house in Lake Havasu City a few times during the summer and found that the a/c just adequate as long as the car wasn't left out in the sun (parked in the garage when not in use) otherwise it couldn't handle cooling it off when it had sat in the 110-120 F heat. Dark tinted windows are a big help.

    Shifty, I donated the 280 to KOCE last year due to old age and problems passing smog. The CIS injection was having problems and it would have cost me $150 (if it was just oxygen sensor) or over 1K (if it was the fuel distributor itself). It still looked good and ran good even running real rich. I'm just thinking about buying a classic SL........
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    great---buy either a 280SL or a stickshift 230SL....those are the best. The V-8 SLs are heavy gas hogs and drive like Buicks...well the 560SL would be okay....
  • burdawgburdawg Member Posts: 1,524
    The older single cam or newer dual cam?
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    There's a dohc 280SL?
  • burdawgburdawg Member Posts: 1,524
    Yes, but not many were sold in the US.. Mid 80's or so. There was a nice one on Ebay recently, it's gone but here's a link to another: http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&item=4545803916&category=633- 8&sspagename=WDVW

    They crop up from time to time. I like the later body style more than the earlier.
  • benzgallobenzgallo Member Posts: 1
    The real issue is probably the ACC Mono Valve. The valve which allows hot water to circulate into the heater core is notorious for breaking down as these cars get older. Symptomatically, the car will blow cold air until you start moving and it will refuse to change out of the defrost setting as far as the blower is concerned. You can get one from adsitco.com for about $150.00. It is a real [non-permissible content removed] to change but in my case, once I did it, HVAC returned to full function
  • burdawgburdawg Member Posts: 1,524
    107 body SL's with 2.8's were not sold in the US, they're gray market only. It's obvious when you see the non 5mph bumpers.
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    Is that the one on the firewall by the glovebox?

    His car may have a different system, depending on the year.
  • burdawgburdawg Member Posts: 1,524
    Yes, I thought that by 79 climate control II was in use in all models. Could be wrong. If it's Climate control I then it's a mono valve, not servo valve.
  • 300d300d Member Posts: 6
    Hi I own a 85 300D and was wondering if any one knew of a place to buy after market head light. Not just oem parts but some of the new and nifty stuff they have out now a days like projector or halo head lights, neon instrument clusters... etc.
  • whaler1whaler1 Member Posts: 1
    Hi everyone-

    I'm a new 1984 300D owner. (97,000 little old lady in a garage, no kidding)

    I have been driving everyday back and forth to work for three weeks and have just started noticing that the accelerator while stick (returns to idle very slowly) when the car is just started "cold". After the engine gets up to temp the throttle is very responsive and shows no indication at all of sticking?

    Thoughts anyone?
  • jlusijlusi Member Posts: 3
    burdawg

    Yes, both are cracked but not really torn. No mechanic thought they were bad enough to warrant changing. but then again no one has yet to fix the noise. By the way I have gotten a bit nihilistic about it. Since the noise is so elusive as it happens only once in about twenty miles or so and has no apparent affect on the stabilty of the car I figure if it gets worse it will just allow me to find it. My latest scheme may be to hook up a small tape recorder with a bungee cord around suspected areas to see if I can pinpoint it. I never mentioned that I frist changed the center bearing as it was kaput and was very bummed to here the great mystery noise still rapping with mechanical immunity. lastly as I mentioned there seems to be just a bit of "play" in the drivetrain when i quickly pump the accealorator on and off...not so esxtreme with a diesel,, I do seem to be able to make the single baby rap happen..almost a clicking sound. So whatever it is I think it is defintely somewhere in the rear part of the drivetrain...I would hate to drop five hundred on anything that is still just a suspiscion. In the meantime I am trying to stay around town under thirty where the noise doesnt happen. IAny thoughts?
  • burdawgburdawg Member Posts: 1,524
    Well, if the boots are just cracked and not open that's good news since it won't allow moisture to get in and contaminate the lubricant. It fairly common to have these boots crack on the high points outside but not crack all the way through. It's something to be aware of and check from time to time. If the exhaust pipe runs close to one of the boots then it will most likely be the one to fail soonest.
    This is just my opinion, but unless your getting some vibration at highway speeds I would do nothing at this point. The noise you hear is very infrequent, and could caused by a number of things. These can be hard to find since you can't really duplicate the conditions unless your driving the car with the wheels on the ground. Jacking the rear up and running it with the tires off the ground to try to duplicate the noise probably won't help since it changes the drive axle angles on the IRS suspension. If it is a CV joint with some wear it probably will be OK for a long time, and you'll know when it is really bad since it will be noisy much more frequently.
    I remember how I had a very strange noise on the 280 I had for a long time. It would always occur when the engine would reach normal operating temperature, and then would occur again when it cooled off. There would be a loud, muffled pop from somewhere in the engine bay. This went on for some years with no apparent ill effects until I finally decided to try and find out what it was. I let it sit in the driveway running until it would pop and then shut it off and let it cool until it popped again while listening and trying to determine where it was coming from. Of course this took some time and I did it over several days, but I finally localized it to the bottom of the engine. It turned out that it was the lower oil pan cover, which at some point in the cars life had been dented in the front. When I jacked it up and watched it during the warmup, cooldown cycle you could actually see it flex when the pop occured, it had been dented just right to flex under these heat/cool conditions.
  • vondieselvondiesel Member Posts: 1
    Hi...owning an old diesel or any old car, one needs to know more about cars than one may want to....I inherited this car (140,000k) and it was running ok..all the nornal problems etc.,...now...it will not shift properly and I've been advised to seek a second opinion and confirmation that it may need a tranny rebuild...it shifts through the gears very fast, if at all, somtimes starts in 2nd,3rd or 4th? but can be shifted manually to achieve some semblance of speed...any suggestions on possible faulty transmission part rather than complete overhaul???? Also, anybody in the MA area who knows? of a reliable transmission shop??? Thanks for this forum...it's excellent!
  • confederateconfederate Member Posts: 2
    I have a1980 300CD with 300,000miles. Steering has play as you could expect. I have been told that an adjustment exists to remove the play in the steering box but I can not find the screw,etc, to make this correction. Can anyone describe the location of this adjustment.
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    Don't MESS with that if you don't know what you're doing--PLEASE!

    Also, I really doubt this is the problem. I'll bet you need front end work. Your car has an enormous # of miles on it and you've reached the point where you need to go over this car carefully and look for freaky kinds of metal fatigue and suspension failures. Look at the arm that comes off the steering box, at your shock damper while you're at it.

    If the front end is all tight, then your steering box is just worn out. I mean, it should be anyway so not the car's fault.

    But I bet you have some bad link or bushing or some such. The front ends are pretty sturdy on these cars. Mine had about 252K on it and it certainly needed some front end work when I got it, but not too much.

    A good front end place can spot the problem quickly and show you exactly where the play is.

    You can buy any part for this car so don't worry about that.

    Good luck and make sure your good old car is SAFE.
  • burdawgburdawg Member Posts: 1,524
    Shifty is right, there's no "adjustment" for steering play on your MB steering box like on older US made cars with worm/sector steering boxes. There is an external adjustment on the bottom but it's for setting the initial top center position and should be left alone. More than likely you have worn steering link parts or the steering gears in the box are worn out, or a combo of both. One thing you can do is have someone watch the pitman arm on the bottom of the steering box while you move the steering wheel back and forth. See how far you can move the wheel without ANY movement of the pitman arm. If it's all original I wouldn't be surprised if you had 1.5"+ of play in the wheel just there alone, but there's so many other wear parts (tie rod ends, drag link, idler arm, not to mention ball joints and control arm bushings) that can add to total play it's hard too determine without a complete inspection.
  • isellhondasisellhondas Member Posts: 20,342
    I knew a guy once who attempted to "fix" his loose, worn out steering by messing with the steering box screw.

    You have NO IDEA what it ook to get that box re-adjusted AFTER he spent hundreds of dollars properly replacing the worn out front end parts.
  • diseldandiseldan Member Posts: 1
    Mr Shiftright,

    This is very valuable information. I can apply it to my 1978 300D. Thanks!

    I have a transmission question. My 300D has a weak reverse gear. I can feel it engage but you have to be on a level surface and rev the engine to get it to roll backwards. It also tends to take a long time to shift between 1st, 2nd and 3rd gears. I noticed here http://www.transmissionspecialty.com/parts/parts/68942-01.htm that it can be a specific valve spring broken...but this transmission they are talking about has 4th and 5th gear. Can you identify which tranny I have in my 300D and how I can rectify this problem? Does this same fix apply to the trans I have?

    Can reverse be brought back by tightening the band once the spring issue has been rectified?

    Thanks in advance for your information and advice!

    Dan
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    That spring refers to a DELAY in engagement. You have slippage. I think you have a real problem therefore with no remedy except overhaul.

    Best thing you can do is drop the transmission pan an take a look in there. If you see lots of debris, then that's it. If it is spotlessly clean, you might do a service and adjustment and see what happens.

    I've never been in one of those trannies so I can't tell you any specifics, sorry.
  • confederateconfederate Member Posts: 2
    Thanks for the advice. I will get a pro to go over the front end.
  • wedgeii1wedgeii1 Member Posts: 4
    I have a 79 300d. I went to start it this morning the engine turned over two times and stopped. The battery is strong the glow plug light turns on but I get nothing when I turn the ignition it has power but the engine does not turn over.
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    How do you know the battery is strong? If it's more than 3-4 years old, on a diesel car that's history for that battery. Diesel cars require much stronger batteries than gas engine cars, and they don't last as long as a rule.

    You should do a load test on the battery and see what you got first of all. If the battery checks out great then you need to measure the starter motor current draw.
  • wedgeii1wedgeii1 Member Posts: 4
    battery is new as of 3 months. when I engaged the ignition the motor turned strong about 2 times then nothing. Dash lights will not dim when I engage ignition.
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    try a jump start--if that doesn't do anything, hook up a remote starter switch to the starter motor (they are cheap, a couple bucks) and thus you can by-pass your ignition switch. This won't start the car (as the glow plugs won't be activated) but at least you can tell if the starter motor cranks. If your starter motor won't crank with a jump start battery in place and a proper remote starter switch hooked up correctly, then you either have a bad starter motor or your engine has just seized from some kind of hydraulic lock (unlikely).

    Does the starter make any noise at all?

    Oh, juggle your automatic trans lever and run it through the gears. Your neutral safety switch could be bad or the linkage out of whack----forgot that.....(this is the switch that will not allow you to start the car in gear). To access the neutral safety switch you may have to crawl under, I don't recall. You can probably bridge that switch to bypass it and then test everything.
  • 300cdveggie300cdveggie Member Posts: 15
    I have a '84 300CD that suddenly won't start. The key won't turn in the ignition past the run position and this the starter won't turn over. The glow plugs work and I can start the car by hot wiring the starter at the three terminal connection above the passenger side wheel well (in front of battery) so i know the starter works. Is there some vacuum lock or other lock that is physically preventing the key from advancing? I've tried both park and neutral. It just stopped working out of no where.

    Perhaps I need a new ignition switch, but I want to make sure its not something simple first.

    Any help would be appreciated.

    --jeff
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    Could be the neutral safety switch, definitely.

    You can check the starter for current from the ignition switch. Might take two people to do this, one with test light, other working the switch.
  • 300cdveggie300cdveggie Member Posts: 15
    It was the neutral safety switch. The previous owner has dropped change, sunflower seeds and a screw in the gear shift housing. Once I got that crap out of there, it started up fine!

    Thanks.
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    Sunflower seeds...i love it....
  • wedgeii1wedgeii1 Member Posts: 4
    Where would I find the neutral safty switch on a 79 300d? If the NFS is bad will the car start in neutral? My car does not, it seems like a lo0se wire because I get no drag from the starter like dash lights dimming when I engage the ignition.
  • wedgeii1wedgeii1 Member Posts: 4
    Okay

    I can jump it at the starter. Any ideas?

    it's a 1979 300d
  • 300cdveggie300cdveggie Member Posts: 15
    We had a persistent leak from our oil cooler hoses on our '84 300CD. Here's how I fixed it.

    First, I found reasonably priced replaced lines from a discount OEM shop online. I went through the hassle of disconnecting the lines, draining them (as much as possible) and then tried to pull them out. No dice. They are rigid from a good length and run between parts of the engine and frame. I connected them back and ran for quite some time with a leak. No fix.

    Then, through another project, I found a hose fabricator in South San Francisco called Adam Hill. They mainly make high pressure hoses and connections for hydraulics. Working with their shop guy, we figured the correct metric fitting (9) degree elbow on the attachments to the oil cooler and straight fitting for the attachment to the oil filter housing. I then removed the fittings on each end if the original cooler hoses, drained them as best as I could, then cut them out with a hacksaw.

    I then ran the hoses around the engine, instead of between it and the frame. Get a stubby 1 and 1/16" wrench to remove and install the fittings. There isn't much room to move the wrench, so patience must be in huge supply.

    Hope this helps someone.

    --jeff
  • phidelphidel Member Posts: 2
    I just bought an '84 300D and it's just beautiful to look at. I want to do whatever I can to keep it running as long as possible. I've never had a diesel before and don't know what needs to be done by way of maintenance. Is there a checklist somewhere of things that should be done, how often they should be done, etc? Can anyone recommend a good maintenance and repair manual? Is the Haynes manual any good? I've used them for other cars in the past.
  • burdawgburdawg Member Posts: 1,524
    Maintenance on the diesel is about the same as any other MB. Frequent oil changes, trans service, cooling system. In my opinion the Haynes manual for MB cars isn't worth the paper it's printed on, it will only have the basic info. The factory manuals are much better but also much more expensive. You can get them on CD now for a lot less, but I wonder how good the resolution is if it's scanned.
    You will probably have more problems with the climate control and body systems than with the drivetrain. A factory manual would be much preferred for those type of problems. Again, these are just my opinions, everyone's experiences differ somewhat.
  • burdawgburdawg Member Posts: 1,524
    Change the fuel filter more often on a diesel.
  • jmul54jmul54 Member Posts: 1
    i just purchased a 1985 300 CD 158,000 miles and well cared for. the body has no rust and interior is in very good shape. i have three problems, the tack doesnt work, the cruise doesnt work and i think the ignition switch is going bad, i have to manually turn it back after starting. from reading post here it looks like the most common problems is the amplifier has been the main problem for the cruise, how can i double check to see if that is the problem? any suggestions on the tack or switch? if i was to purchase a amplifier what do you suggest (in percentage) that is the problem. It has new brakes & rotary's, drives great and uses no oil, doesnt smoke. i changed two injectors that were leaking very small amount of diesel and that helped. it seams to be a strong engine and the trans shifts real good. thanks for any help. Also which do it yourself repair manuel does anyone suggest for this car?
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