Mercedes 300D Suggestions

mdyoung1

THANKS. GOT ANY IDEAS ON FIX UP STUFF-ENGINE PERFORMANCE, TIRES/WHEELS, ETC

Mr_Shiftright

don't waste your money on any of that is my advice. Just change the oil frequently, change your fuel filters (two of them) every 3,000 miles, use a fuel additive like Redline, and use factory filters at all times. You can't make it go faster and the stock wheels and tires are fine.

slugworth

My air compressor was recently making some awful sounds when I turned on the defrost. My brother diagnosed it and unplugged the air compressor - sound went away. Later, somehow the belt got twisted when I was on the highway and I cut it off. Everything seems fine since. Will I experience any problems if I just leave this belt off? I haven't had AC in my cars for years, so I'm fine without it. Just not sure if it is has some other vital function that I don't know about.

Mr_Shiftright

What kind of car is this?

slugworth

oh yeah -
a 1983 300D Turbo.

Mr_Shiftright

yeah you can just disconnect the AC compressor. I don't believe that belt drives anything else. If the AC compressor actually seized while running, then the whole AC system is contaminated with debris, so it would be a very expensive fix for you to get AC back.

wvoplush2

Last summer I drove my 82 300D Turbo (220K) from coast to coast and back--loaded down fully and experienced virtually no problems--except that persistant oil leak...and I must say I am super impressed with this car...

but now finally my brakes have given out.

the mechanic who did my pre-trip inspection said the rear calipers would need to be replaced at some point. The brakes didnt give out all at once--often i could pump them and she would stop. But sooner than later they went all the way to the floor.

What is strange is that it leaked no brake fluid--or maybe a teaspoon at most. If the calipers were bad--and correct me if i'm wrong--wouldnt this mean the caliper pistons were leaking fluid?
Or maybe the brakes failed because of another leak? Does my problem sound like the brake master is leaking internally, or maybe something inside the brake booster, and consequently no external fluid loss but still a loss of pressure?
I am kind of a dummy when it comes to brakes, so any extra experience with this would help. The parts are expensive and I dont want to spend all my life savings ($800).

This forum has always treated me right :shades:

brillanze

Get the parts and do it yourself --it's an easy fix --you can get ATE (or Bendix) calipers at O'Reilley's for about $50.00 each (or buy the parts yourself and have the mechanic put them in). Pads are way cheaper if you buy them yourself, too.
Sometimes the brake lines get air in the system--the brakes need to be bled-this would cause the brakes to fail with no fluid loss. You might try having the brakes bled first, but the seal in the caliper may be letting air in the lines. Smile--once you replace the calipers, you shouldn't have this problem again in your lifetime. I think the Mercedes needs to have the brake fluid changed out every couple of years or so, anyway. Good luck.

ewvdt

After you have replaced the brakepads and checked all brakelines and calipers for leaks, you may well have an internal problem with the masterbrake cylinder.
Extenally there should be NO brakefluid leaks at all. A teaspoon size leak should tip you off as where to start looking. Hope this helps.

ryan77300d

I recently removed the better part of my dash board and glove box to get at the glove box interior light. (someone had removed it, and then just stuffed it randomly deep into the dash so they didn't have to deal with it) I found the light after I noticed it lighting up through a space behind the ash tray when the glove box was opened. Long story short, I temporarily lost the glove box latch and had to drive around with everything buttoned up, but the door hanging open. As I looked for a new latch, I taped the door shut with electrical tape. (Should have used painters tape, but this would have meant walking all the way to the tool box) After fixing everything, I took the tape off and @#%&! There are now glue-marks from the tape. I've tried cleaners, abrasives, paint thinner (used in a VERY controlled manner) etc. What can I do? Could I use the vinyl interior 'paint' made for touching up auto interiors? This dash is mint, no cracks or defects other than the glue spots, I would hate to ruin it. Any ideas? Thanks in advance.

-Ryan

wvoplush2

Thanks!

I called Napa and they had a similar price. I havent gotten under the car yet, but im just gonna do the calipers/pads anyways since the mech said it was time--and then see how it goes from there. Thanks for the quick response!!

burdawg

Have you tried Desolve It cleaner?

ryan77300d

Thanks! I'll start looking for that brand, as those marks just bring down the whole interior. I'll post back if it works/not.

-Ryan

burdawg

I've used Desolve It for years for tape residue, adhesives, etc. It may take a little time and a few applications, but it's gentle on materials and your hands. I recently used it to get this gooey sticky adhesive off the dash panels on my MG. Someone put one of those aftermarket wood dash kits on it, which looked good from 20 feet away but horrible up close. It took all afternoon, but it did the job and didn't harm the vinyl underneath.

Mr_Shiftright

You gotta remember not to rub TOO HARD, no matter what you use. Take your time...apply, dab, brush very gently...reapply, etc.

Also, test the stuff you are using on an inconspicuous part of the dash before you go at it.

Take---Your---Time.

richtrea

richtrea

I have just bought a 1988 300D. I have enjoyed reading through the posts on this site although I now understand I probs paid way over the market value for the car -
it has done 315K (paid AU$9000). It has a few oil leaks and minor issues such as no handbrake and the CC doesn't work properly. Love the car, it is generally in top shape and I think that 300Ds are pretty rare here in Western Australia.
But the dashboard switch for the rear headrests will not drop them - even when pushed repeatedly with the car running.
I understand that the system is driven by a vacuum system -
but is it possible to get the headrests down manually? I got the cover off from inside the boot - the mechanism sure looks sturdy. Many Thanks. Rich

rangner

I use redline diesel fuel catalyst in my 87 190DT at a mixing rate of 1oz to 6 gallons of diesel to help my seals.

As you know higher sulphur diesel has aromatics that our engines were designed to be fueled on to lubricate the seals and injection pump etc.

Does anyone have an idea as to how much more fuel catalyst needs to be used given the fact that the sulphur level in diesel is now going to be 5ppm instead of 500ppm?

I'm going to ask redline and see what they recommend.

Eric

bdsmacher

I recently bought an '83 300SD that sometimes keeps running after I have turned the key off. If I hit the brake, though, the engine stops. Is that still likely a vacuum leak?

The other question has to do with the vehicle stalling. I've driven the car on short trips around town (1-2 miles) and it seems to run fine. But yesterday I took it on the highway for a longer trip, about 20 miles or so. There were no problems on the highway, but the car stalled when I exited at the end of the exit ramp. It started and ran for a few secons and then died again. When I tried to restart it, it would die after shorter and shorter intervals with each attempt (I was trying to get it to the side of the road).

I had the vehicle towed back to my place, thinking that maybe I was actually out of gas and the gauge, which read 1/4 tank, was just incorrect, but there was fuel visible in the filter. It took about an hour to get the tow truck and get back, and then my car would start again and run. Any thoughts on why this might be happening?

Thanks

Mr_Shiftright

Well with any Benz diesel first thing you do is change both the fuel filter, put in fresh fuel and a strong injector cleaner, then adjust the valves. These are the common points of neglect on old Benz diesels....dirty fuel, clogged filters and tight valves.

And yes, you have some kind of vacuum system problem. If the leak is big enough, it might also affect the running of the car and the stalling.

But you'd be amazed what clean fuel, filters and a valve adjustment can do for these cars. Maybe somebody has been running some weird "biodiesel" concoction in there and didn't know what they were doing.

If you are in the San Francisco area I can recommmend shops that actually know what they are doing and won't rob you blind.

bdsmacher

Thanks for the maintenance advice! I was expecting to have to do some work on the car since its older, but it would be nice if the repairs/maintenance were straigtforward (and inexpensive, of course).

I'm actually in Honolulu, but if by some chance you happen to have any leads on good mechanics here (or if anyone else does who happens to read this) that would be great. I have a guy that I liked for my previous car, but that wasn't a diesel and I'm not sure if he crosses over.

I'm pretty sure the vehicle is running on regular diesel, but I would like to run it on biodiesel once I get the fuel lines changed. There is a commercial company here that sells it at the pump that I believe produces a reliable product.

Cheers

ryan77300d

I'm doing a valve adjustment on my '77 300D at some point soon, and I thought that would be a good time to replace the timing chain as well. The car has 116,000 miles on it as of now. I've heard it's recommended to replace the timing chain spockets and tensioners as well, but is it really necessary? I'll probably do it 5 years from now, or should I just get it over with and do it while everything's apart? I've heard that the timing chain guide rails wear extremely little during thier service life, so I'm skeptical about spending money on tensioners and sprockets.

Thanks in advance

-Ryan

Mr_Shiftright

I don't know why you'd even replace the timing chain as long as it isn't making any noise. I think you can just test the free play. Mercedes has a tolerance range, I'm sure, that you can test for.

burdawg

I didn't think timing chains were any problem on the diesel. My memory is that it was recommended on the V8 cars with single row chain (at about 100K miles), and to install a double row.
If I remember right, you check the timing chain play by measuring how far the tensioner is protruding out of it's housing.

ryan77300d

Thanks!

Better that I don't spend money on sprockets, tensioners and chains to boot. I'm basically going by what I read off of a parts site, which has how-to's on it as well. It states to change the timing chain if there's a tick over 100,000 miles on it, and to change the sprockets and tensioners. (Coincidently, after every sentence about changing a part, there's a clickable link directing you to thier Parts Purchase page)

I also asked my auto teacher about it, and after I said "115,000 miles" and "original timing chain" in the same sentence, I got a horrified glare.

I'll do the procedure for checking slack in the chain, just to be on the safe side. Better than throwing money at it, that's for sure.

Thanks again

-Ryan

Mr_Shiftright

Well they can act horrified but I don't think they're right about this. Are they confusing "chain" with "belt"? Sounds like it.

A Mercedes timing chain is strong enough to drag an elephant to the vet.

hoofen1

hoofen1

Man is my beloved 85 CDT ever getting sluggish,barely gets up a hill lately;once it hits 2.9k rpm it picks up some as the turbo kicks in.Any ideas??Also,somebody whacked me and I need a replacement turn signal lens for the right front,parts stores don't have them it seems.
Any help would be appreciated.
Thanks
Hoofen

Mr_Shiftright

the standard diesel "tune up" is first thing you do. New fuel filters, adjust the valves, dose it with very VERY strong injector cleaner and see how it runs.

hoofen1

Thanks,I'll give that a try and let you know how it turns out.

nigel6

I have a 1985 300 CDT. I had parked it up for 8 months and recently got it out again. I put a new battery in but struggled to start it. It started and ran fine before I left it even on cold mornings.The glow plug indictor light was on at first then stopped coming on. I checked the the glow plugs and found that one was not working. I replaced it and the glow plug indicator light operated as it should. It was still hard to start, so I checked the relay and that was ok. When I do manage to get it running it runs fine and starts up without a problem. I am wondering whether it could it be lack of compression (oil pressure is good), or fuel gelled up. It runs as good as it ever did once I do get it running. Can Glow plugs fail gradually, or do they either work or not work? I am trying not to spend money if not essential, but would it be better to change all the glow plugs? I am thrown off by the fact it started and ran great when I parked it up 8 months ago, even in the cold, and now when I finally get it going it will start and run no problem. Is it just the cold weather ???? I Have a block heater that apparently fits somewhere on the block and you need a 19mm allen key to get out the block plug but as of yet I haven't found a 19mm allen key, nor do I fancy my chances of getting the block plug out when and if I locate it! Any suggestions or advice would be greatly appreciated. Thanks!

Mr_Shiftright

Replacing all the glow plugs would be a good idea. Also you need a good strong battery to spin the engine fast enough...remember, it is a compression engine...that's all there is to ignite the fuel...the glow plugs just warm it up a little. A block heater would certainly help.

19mm is just a bit short of 3/4". I would use a 19mm or 3/4" allan socket wrench with breaker bar....but not too long a breaker bar, maybe 18" tops.

I think glow plugs are only $15 apiece or something like that.

A fuel additive is always a good idea.

nigel6

Thanks for the advice. Do you know exactly where the core plug is I need to remove to fit the block heater and what method I might try to loosen it? Can I get at it from the top or do I need to be underneath the car? Thanks again

Mr_Shiftright

You know I don't remember. I always thought it was on the passenger side of the block somewhere. Living in California, I never needed one. :P

Diesels are a b**ch in cold weather and they need all the help they can get. Anti-gel, top notch battery, new glow plugs, light engine oil, block heater...the colder it gets, the more of this stuff you need for reliable starts. In severe climates, some truckers NEVER shut their engines down for more than a half hour or so. They run all winter more or less.

My last diesel was a GREAT running and starting car, but as soon as it hit about 20F, things got ugly.

nigel6

On the subject of difficult starting, lets say the fuel did gel up on a cold morning and the fuel filters got clogged, would the gelled fuel liquify once car heated up or would the filters remain clogged and need replacing? The temperature is warming up here this week,supposed to be 50s 60s so if it starts ok then I can put it down to the cold and work on fitting the block heater. All advice and suggestions welcome and appreciated. Thanks

nigel6

Mr_Shiftright

This might be helpful.

http://alternativefuels.about.com/od/vehiclemaintenanceguide/a/dieselcoldweath.h- tm

It's my understanding that diesel fuel will start to gel at about 15F....so as it gets warmer than that, the fuel will flow more freely.

ryan77300d

Don't know if this will help, but it sure works for me.

During the winter days up here, the temperature lately has been around -6F. To start my car after it's sat in the school parking lot for 8 hours, I let the glow plugs cycle once, wait for the light to go out, and then cycle them 2 more times while pumping the throttle pedal 3 times/cycle. Then, I engage the starter (sparingly, as there's now barely any battery left) without depressing the throttle. When it fires once, after 5 seconds or so, I floor it and it starts right up. (Obviously I don't continue flooring it then)

This is very much a starting ritual when the engine is stone cold. When warm, it starts w/o the plugs. I'd imagine doing the same for an engine that hasn't run for a long while would work great.

-Ryan

(Of course, I put anti-gel in the tank)

Mr_Shiftright

Good practice for what sounds like tough conditions but you can forget the throttle part...that's just an air flap on a Mercedes 300D--it's best to just leave it closed when starting...it acts like a choke of sorts. It has nothing to do with fuel.

You could pump the throttle 600 times and it wouldn't do a thing. :P

ryan77300d

No throttle? Really?

That's good to know...the manual says to "depress the accelerator energetically before engaging starter", but I was wondering myself how that would have any effect on an engine that wasn't already running.

Saves me energy at the least

Thanks!

-Ryan

Mr_Shiftright

Is this a manual for a GAS car? Diesels generally run by metering the air intake. Pumping the gas only works for a gas car with carburetor AND accelerator pump...or...if you are clearing the cylinders of fuel in an injected car.

Pumping an old MG with SU carbs is equally useless, as there are no accelerater pumps in the carbs.

so I dunno, maybe I'm missing something here about starting a diesel, but (scratching head) I can't see why working an "air pedal" would have any effect on a 300D.

manc

I couldn't resist pulling nearly perfect front seats out of a 1991 190e (201). The car had 105,000 miles but looked like it had 30k. It was pristine. I am trying to take the easy way out and ask if anyone has used these seats in their 123 bodied car. The seat rails are at least 1 inch closer than on my car. I have a 1983 300d with awful front seats. I would imagine it will take some creative engineering. Any ideas?

Thanks in advance, Phil,

Mr_Shiftright

Well this is a welding job. You don't want to secure your seat merely by drilling a hole in a sheet metal floor pan. You need to weld in anchoring points, preferably pre-threaded supports but really any heavy piece of steelplate would do.

nigel6

Iv'e no experience with turbos, how do I check if it is working properly.My car seems to lack power and I wondered if the turbo was actually working ? Thanks

Mr_Shiftright

It would be best to check other things first. Does your diesel have a "trap oxidizer". If so, they get plugged and are a likely source for your complaint.

Have the valves ever been adjusted. Another way to lose compression and power.

Then do a compression test. If your MB has a lot of miles on it, this could be the cause...the cylinder get kind of oblong on these cars and compression drops accordingly---they become hard to start and lose power as well.

Best way to check a turbo is with a boost gauge.

So....check trap oxidizer, adjust valves, do a compression test, THEN worry about the turbo....without good compression, your turbo is of no use anyway.

nigel6

I have a 300cdt and among other things the speedo doesn't work. Is it a faulty cable or could it be the clock itself ? The Trip meter doesn't work either. Any suggestions as to where to start. What kind of job is changing the speedo cable ? Whats the most common fault ?

richtrea

Get access from the trunk. The mechanism can be released by pushing on the linkage that sits on top of the black plastic vacuum canisters - there is one for each headrest.

boomchek

I heard it's a common problem on old Benzes, where the odometer or speedomoter stops working.

My parents had a 77 300D in which the odo stopped working but the speedo worked fine.

Not sure if you can just replace a cable or if you will need to change your whole cluster.

ewvdt

This is a common problem after these cars reach a certain mileage. The gear inside the odometer starts to slip on its shaft. This can be fixed by putting a small drop of super glue on that area.

nigel6

I am not sure if my car has a Trap Oxidizer ? Its a 1985 and I believe it was a grey import? How can I tell if it has one ? I read something about MB doing a call back and replacing the trap oxidizer ???

P.S what is the correct engine oil for a merc deisel ? I have read differing articles. Thanks