Replacing engine mounts, etc - level of effort?! - PeachParts Mercedes-Benz Forum

MercFan · #1 12-29-2004, 12:29 AM

Hello -

Still looking for a nice dependable MB diesel to be my faithful daily commuter. Today I've looked at one: '82 300D (inside the door it read Model 123D) with 197K, asking $4K.

The car is in excellent shape especially on the outside though a bit worn out on the inside, but it seems to run strong and the owner (3rd) had invested some money into it so it looks like a solid car.... but it has few things that need attention:

1) At idle, it shakes noticably, so it probably needs new engine mounts - question here: how hard is it to replace those by a rookie back-yard mechanic like myself?! Instructions available anywhere?! Where would I get the OM parts from and for how much?

2) The owner said that the rear CV Boots (?!) will need to be replaced evenually.

3) The owner admitted that the rear brake lines are showing cracks and will probably need attention.

4) The transmission has a bit of a late shift in 2nd and 3rd so maybe a vacuum issue. The owner had the Vacuum modulator replaced recently because the housing on the old one had cracked?!

5) The transmission fluid and transmission filter are probably due for a change.

Are these the kinds of repairs that one with basic mechanical skills and a lot of enthusiasm could hope to complete in a reasonable amount of time? If not, what would be a rough estimate of repairs.

Anything else I should watch out for on this model before making an offer?

THanks,
James

JimmyL · #2 12-29-2004, 12:45 AM

I'd make an offer alot closer to $2000 than $4000, but it's not like I was very smart when I bought mine, so take that with a grain of salt. You are doing the right thing by first educating yourself on these cars and THEN getting one. Whatever you do, good luck, and post photos.
JL

Jimmy Joe · #3 12-29-2004, 12:48 AM

What part of the world are you? (location on posts helps)
RUST is a biggy to steer clear of.

MercFan · #4 12-29-2004, 01:06 AM

Quote:

Originally Posted by Jimmy Joe

What part of the world are you? (location on posts helps)
RUST is a biggy to steer clear of.

I'm in Denver, CO (signature updated now...) The car has only two small rust spots on it - not bad for a 22 year old vehicle. I think it's a beauty...

Is there a compound one might use to "seal" the rusty spots and stop the rust from spreading deeper?!

BTW - here's the pic:

Pete Burton · #5 12-29-2004, 08:27 AM

To really look for rust, you need to look around all 4 wheel wells, inside and outside. Jack points, under battery, bumber supports, behind headlights, where sway bar is mounted either side. Frequently, rust is behind the undercoating and pushes it out somewhat. Press as hard as you can with your thumb all along these areas. If it's even a little spongy, there is rust.

KCampbell · #6 12-29-2004, 09:35 AM

Here's my thoughts, as a newcomer to these things myself:

1. May not be engine mounts. On my car the rack damper pin on the injection pump could be adjusted to improve idle shake in a big way (do a search you'll find lots of info). One of my engine shocks had broken and replacing it helped even more.

2. This is a true statement for any vehicle that employs CV boots

The 300d has an independant rear axle, and uses constant velocity joints rather than U joints - just like a front wheel drive car. These joints are covered by rubber boots that eventually crack and must be replaced. It appears to be possible to replace just the boot, rather than the entire axle, but this isn't something I've looked into. Yet. It would be worth evaluating for yourself how bad they are, some surface cracking is OK, but if they're torn they have to go.

3. Assuming he's talking about the flex hoses, no big deal. The hoses are not expensive, and not hard to change. I replaced all the brake flex hoses on my car as a matter of course, along with flushing the brake fluid. With any old car this is one of the first things I would always do, unless you have receipts indicating it was done very recently.

4. Lack of vacuum won't affect when you get a shift, just whether it's a hard or soft one. There is a cable linkage that probably needs to be adjusted - search for bowden cable I think.

5. Yes they probably are. Again with any old vehicle I always start by changing all the fluids and every filter so I have a good base from which to start.

Does the climate control work properly? Do the buttons correctly change where the air comes from? Do you get heat to both driver and passenger feet? Does the central locking work OK? If all this is good and your shifts are fairly smooth then you probably don't have vacuum leaks.

All the things I have tweaked on my car were easy to deal with, and none of them fundamentally affected my ability to get where I was going. I've sorted out my vacuum system so that shifts are nice, tweaked the ALDA (do a search) to get a bit more pre-turbo power, replaced the injector fuel return lines (the old ones were weeping). None of it was hard, none of it stopped me from getting to work each day.

Kevin

rgp123 · #7 12-29-2004, 12:49 PM

Don't forget to check the floorboards for rust! My education in rust repair came with the '85 300D in my garage. Leaky window seals allow water to go under the carpets and rust from the inside out; very nasty.

Cateaux · #8 12-29-2004, 06:56 PM

Another place to check for rust is in the trunk under the spare tire. Water seems to collect there on alot of these cars by leaking through either the rear window seal or the trim attachments on the C pillar.

One good thing to check for is blowby. All diesels seem to have at least a little, but a lot may indicate a really tired engine. If the condition of the engine is in question, you (or your favorite mechanic) should do a compression check.

Brake hoses are an easy fix, and only cost about $10 or $12 each. The CV boots seem a bit difficult, but doable (if you have access to a large hydraulic press). BoostnBenz has detailed instructions with photographs on his site. Just click on the sticky thread at the top of the diesel forum page (I think it's the second or third thread).

I've spent the last two days tinkering with my transmission, and have almost gotten it to shift smoothly. By searching the forum you can find all you need to know, because whatever old diesel Benz you buy, you will sooner or later have to adjust the transmission. Search for "bowden cable", "modulator valve", and "vacuum control valve"...and learn how to use a mitey vac. You'll need it!

MercFan · #9 12-30-2004, 01:35 AM

Quote:

Originally Posted by MercFan

...but it has few things that need attention:

Just remembered another thing about this car when I test drove it... When I put the car in Reverse (from a dead stop), I noticed that the tranny seemed to hesitate a little before the vehicle started moving backward... The owner told me that unlike today's electronic transmissions this vehicle uses fluid in its transmission and hence the little hesitation...

I didn't know any better but it made me wonder if this hesitation in switching to Reverse was normal or if it was an indication of some bad things to come on the tranny?!

Any help would be appreciated.

James

190D22 · #10 12-30-2004, 02:49 AM

Too bad the newest of transmissions STILL use fluid... The hesitation is a likely sign of the tranny starting to die. When the seals start to go bad it takes a little longer to build pressure... the cause of the hesitation. My tranny died last year and it hesitated when I'd put it in drive. The new one does not hesitate at all. But if there is no hesitation going into drive I would not worry about it.