I just bought my first Mercedes. It's an '83 240D in very nice shape, with 126,000 miles. It runs well except for a very rough idle which may be caused by a damaged driver side motor mount. It runs very smoothly once it's in gear and moving.

Fixing old diesels is my hobby. I currently own a couple of '70s John Deeres and half a dozen '80s Ford diesel trucks, and some Lister generators.


What should I look out for on this new toy, besides vacuum leaks?

What are the trouble spots?

Where do I get a shop manual, and an owners manual?

What is the recommended engine oil?

Are there any specialty tools that are must-haves? Maybe a fixture for my dial indicator for injection timing, like on the old VW diesels I used to have?
What parts should I keep on the shelf, besides obvious stuff like filters and glow plugs?



Other than the motor mount, the only issues I'm aware of are a plugged vacuum leak in the mirrors and the air conditioner belt has been removed. There are the oil leaks on the exterior of the engine that I expect on an old machine, but no signs of rivers of oil, just black crud on the exterior.

Manual or automatic transmission?

There is online service manuals that have free access but the actual real Mercedes Manual Books have more information in them. But there is a bunch of them. 2 chassis manuals, 1 engine manual and a climate control manual. The electrical stuff is in one of the chassis manuals.

Replace the Oil Cooler Hoses if there is any seepage around the crimped on collars.
Inspect the Rubber Flex Discs on the Drive shaft for cracks. On a 240D I don't know how hard the front one is to see but on an 84 300D the front one is hard to see and in my case I removed stuff to get a good look.

All of the suspension control arms pivot on the elasticity of the rubber. When the front ones go bad you get either inner or outer tire wear and it can be very aggressive.

The rear is less noticeable. When my trailing arm bushings and the rubber sub frame bussing's where no good. I got kind of a squishy feeling in the rear when maneuvering and turning. That was recognizable because I had owned the car for a long time before they went out.

Notice that a good deal of the issues concern 30+ year old rubber.

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84 300D, 82 Volvo 244Gl Diesel

Repair Links
Fast navigation Fast navigation Do It Yourself Links

Here is a pic of the differential mount that I replaced. Rubber again.

Before I was a forum member I bought Autolite and Monark Glow Plugs. Forum Members only recommended Bosch (made in Europe not the Indian ones) and Beru Glow Plugs.

I figured I had already bought the brand X ones so should use them up before buying the Bosch ones I bought later.
Well in 6 months 2 of the autolite glow plug tips swelled and I had trouble getting them out.

The Monark Glow Plugs I used just failed early. Used bosch plugs and got good service out of them.

Taking apart the rear well bearings normally ruins the bearings due to the way they are normally taken apart and you need a special tool.

Also these cars don't often tolerate cheap Atozone type parts.

Look up the Motor Mounts. On mine Phoenix makes the ones the Mercedes Dealer sells and Lemförder/Lemfoerder/Lemforder grinds off the Mercedes Star from the Motor Mount and boxes them under their name and they are made in Turkey.
Lemförder/Lemfoerder/Lemforder makes good quality parts at a reasonable prices. In particular their front lower ball joints are made in Germany.

No Chinese flex discs. Lemförder/Lemfoerder/Lemforder also makes those and I have them on my Car. Good price excellent quality.

Attached Thumbnails

 

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84 300D, 82 Volvo 244Gl Diesel

Check the valve clearances. Past owner tend not to do that. There is a special wrench set but it can be done with regular wrenches if the heads are thin enough. A few say they have done it with the Fuel Injection Hard lines still on. If you are using regular wrenches I would have to remove the Fuel Injection hard lines.
Personally I waited till I bought the special wrench set used on eBay and later I made some and sold some (no more though). So you can make your own and that is in the repair links.

Look in the repair links for the Fuel Injection Pump timing. You don't need a dial indicator for that.

I have owned a car since 1968 and have always done my own work on them Since that time I have always adjusted the front wheel bearings by hand with no issues.
When I did that on the Mercedes I got it too tight and overheated the grease (the Mercedes service manual has to use a dial indictor I had 2 dial indicators but had not used them for like 5 years and I did not want to look for them).
So I ended up having to pull the front wheels of clean out the roasted grease and re-install them using dial indicator (took almost 2 hours to find the indicator and the magnetic stand I also strictly followed the procedure in the manual).
No issues after that. And over the years when the Front Wheels were off I only used the Dial Indicator to adjust the end play and I never have a problem.
Other say they do it by hand so use your best judgment.

On the rear it is critical to use the Dial Indicator on it.

If you vacuum pump starts making noise pull over. There is a few things that cause vacuum pump failure (in the repair links) and when it happens the parts can fall down into the Timing Chain and Gears and it is possible to damage the Engine to varying degrees depending on how fast you are going during the failure and where the parts happen to fall.

The Power Windows are wired with 2 fuses but diagonally. As an example driver side front and the passenger side rear will stop working when you have a Fuse issue.
Replace any Fuses with plastic bodies as the plastic melts before there is enough amperage to melt the metal strip.

If a single window stops working it is often the window switch itself. You can take apart the window switch (don't loose the 2 ball bearings and 2 springs inside nor the 2 rockers) and scrape off the contact points.

If all of the windows stop there is a single fuse that goes to the power window relay. On mine it is fuse #12 I don't know if yours is wired the same. There is supposed to be a fuse chart on the lid of the fuse box.

I had one front window stop working and scraping the contacts on the witch did nothing. It turned out there was a wire loose at the window motor terminal block on the front door.

It is common for the rear window regulators to bend as the frame on them is made of metal similar to the old carburetors. Real new ones if you can find one was over $350 each. I am not sure if there is an aftermarket maker. There is aftermarket for the Front Window Regulator.

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84 300D, 82 Volvo 244Gl Diesel

People have had mixed success and failure with aftermarket rear axles.

A lot of people like myself have re-booted their own axles. There is at lest 3 threads in the repair links on that.

If you have trouble turning your Ignition Key the Lock Tumbles are know to go bad and some like myself thought they had a Lock Tumbler issue but it was parts inside of the Steering Colum Lock that had broken.

If the key and tumbler get stuck you have to grind off are drill out a pin on to get the Steering Colum Lock out.

I don't know on your year but on mine the Ignition Switch at the bottom of the Steering Colum Lock cannot be removed unless the Key is in a specific position which is also true of the Lock Tumbler.

If you have vacuum but it is low there is a check valve that screws into the Vacuum Pump that falls apart (the loose parts don't ruin the vacuum pump) or sometimes as happened to me it was just gunked up inside.

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84 300D, 82 Volvo 244Gl Diesel

What color is it?
1983 is the best year IMO and others feel that way too.
Last year for the lacquer paint.
I have 2 1983 W123s and they feel better than other years as well.
Cheers

You'd best print out the above comments because they're all dead bang on by someone who's been there and done that .

I love my '82 240D slush box stripper the best of my three old Mercedes and also better than all the various Mercedes' I've owned over the decades .

Cheap to buy, easy to maintain & repair, be wary of off brand & Chinese parts .

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-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better

Just a note- if you have a really rough idle/turn over that smooths out with even the slightest bit on the accelerator, you may be looking at an injector issue.

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1985 300D Surfblau "Blueberry" 250K R.I.P
1984 300CD Manila Beige "The Banana" 238K R.I.P
1984 300TD Cypress Green "Olive" 390K (M.I.A.)
1982 300D Orient Red "Steak" 195K
1985 Euro 300TD Lapis Blue “Pancake” 200k KM
1982 300D Light Ivory “Butter” 183k
1984 300TD Black “Pepper” 55k

Agree, lots of good info from Diesel911.

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All Diesel Fleet
1985 R107 300SLD TURBODIESEL
2005 E320 CDI (daily)

LOTS of parts for sale!


EGR block kit
http://www.peachparts.com/shopforum/diesel-discussion/355250-sale-egr-delete-block-off-plate-kit.html

1985 CA emissions 617 owners- You Need This!
Sanden style A/C Compressor Mounting Kit for your 616/ 617 For Sale + Install Inst.

Sanden Instalation Guide (post 11):
http://www.peachparts.com/shopforum/diesel-discussion/367883-sanden-retrofit-installation-guide.html