Working through my Daughters new 1983 240D

[dmorrison]

The last couple of days I have started to go through my Daughters new 1983 240D. I wanted to get the locking system and vacuum system repaired. Doors would not lock and engine would not shutoff.
Found the front right door lock bad. So I will replace the unit. The 3way and 4way connectors are a little old and need replacing. Found a small amount of oil in the vacuum pump to brake booster hose. So a rebuild of the vacuum pump is in order. I will systematically go through all the vacuum elements in the entire vacuum system and check each one out. So far all doors (except the front right) gas flap and trunk and reserve vacuum tank check out. The ignition switch is also OK. Boost pump will hold a vacuum, Injection Pump shutoff OK. So I'll check all the rest of the systems tomorrow.
Cleaned the entire trunk. 303'd all the rubber and inserts. Checked the tire and jack assembly and tire pressure. I will look into the rear lights another day. Want to make sure the rubber sealing strip in the aft light assemblies are still good so soot does not enter the light assembly.
Have started to detail the engine compartment. I will still have to go over the engine. Valves, rubber, fluids, filters, etc.
Checked the front right suspension. The previous owner rebuilt the front end last summer and it looks good. They did not replace the sway bar mount bushings. I will do this when I R+R the battery tray and the booster.

So I'm finding some things I did not expect, vacuum pump- maybe booster, and somethings that I thought I might have to rebuild, front end, I don't . So its going well.

I'll post things as I go.

Dave

PS Monday we are taking it to a tranny shop for a rebuilt transmission and torque converter. $1100 plus tax installed. I talked to him and was very impressed. Check the BBB and "worked with BBB with any problems. He's been there 28 years. So it sounds good. He'll give a 12,000mi warrentee.

[dmorrison]

Saturday the 21st.
I worked on the car getting it ready for the trip to the tranny shop. That's tomorrow.
I noticed while running the car it would "missfire" sometimes. I was thinking injector. To get it ready for the trip to the tranny shop I wanted to take care of the algae problem. So new filters and drained the tank to check the screen. The diesel draining was rather slow, Hmm screen is probably gummed up.

Ok First. The 45MM socket to remove the screen filter. I have the set from Harbor Freight.

http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=5494

To use this set on a 240D, 300D and 300CD you have to have a 3/4 drive universal. You can not use the ratchet and the socket ( that came with the set) and clear the axle. Since I did not have a 3/4 drive universal. And I do have a grinder. I cut the socket to allow my 32MM open end wrench to attach to the socket end. I chose this option since I had diesel drip on me and I smelled of diesel. I did not want to shower, change and get into the SL with the diesel on me and try to find a 3/4 drive universal. So a little grinding and the wrench would work on the socket.

Well after loosening the screen and slowly removing it the diesel of course came pooring out once the threads had release. I got maybe 90% of the diesel ( maybe 3-4 gallons total) in the container I was using. 5% of it went on me. The other 5% on the driveway . Ahh the joys of working on diesels.
The screen was covered in alge and a gummy varnish. I soaked it in the wash tank, for an hour, and had to use air from the compressor to get it clean.
Replaced the screen, hoses and primary and secondary fuel filters and the car ran without any "missfires". And the diesel running through the primary filter was nice and clean.
I put a dose, actually 2 doses of a diesel algecide and will fill the tank when I can. The sending unit is not accurate, probably algae and such in the sending unit. I'll clean that out when we get the car back. Hopefully this is the case. A new sending unit is $230 for the 240D. Might be cheaper to get a whole used 300D tank and install it. well cross that road when we get to it.
Used a degreaser, and a high pressure washer I have, to clean the underside of the whole car.
I check and found out that the WHOLE front suspension was recently rebuilt. The steering suspension is like new and the driveshaft was rebuilt last summer. This included the center bearing and the flex disks. The rear suspension is a littler older, I will replace the subframe mounts and the trailing arm bushings. The differential mount seems good. Axles seem very good.

Overall the underside of the car is in great shape. As I said I will replace the following
Subframe mounts
Trailing arm bushings
Rotors, fronts are slightly warped. They measure at 11.4mm (min is 10.6) But with the warp I will replace them.
New pads.
Throttle linkage will need some attention. Worn bushings and such but not a lot.
Vacuum pump will be rebuilt
Valves adjusted/new valve cover gasket
New rubber hoses where needed.
New fuel filters in a month or so to eliminate the algae

Additionally over the next couple of weeks I will have to:
Fix the Air Conditioning system. Freon is low.
Interior trim fixes. Minor trim pieces need attention.
Clean and rebulb the instrument cluster.
Detail all the interior.
New radio
Antenna mast
Wax
Looking at European E code lights

And then the car will be up to 95% of "Payton"

And so it goes.

Dave

PS Working at replacing rubber hoses on the vacuum system I slipped a broke one of the vacuum fittings on the booster hose. A $35 oops. Tried to repair it with no success. So I took the one off the 300TD until I can get a new one from Phil.

[kmaysob]

sounds good! is the tranny shot or are you just making sure it doesnt fail? for the shutoff problem try cleaning and replacing the rubber hoses that connect the vac lines to the ignition switch. thats what i did.

[dmorrison]

Well a very interesting turn of events this morning.

As I posted, I worked on the vacuum system last week. Replaced all the rubber 3ways and 4ways. All vacuum connecting hoses. And Isolated the front right door vacuum lock, it was leaking. Still will rebuild the vacuum pump. Cleaned the fuel screen and all filters. Replaced all rubber fuel hoses.
This morning started to drive the car to the tranny shop in downtown Dallas. About a 45 min drive.
While driving the first 20 miles I realized that the transmission seamed to be operating normally. I played with the speed, shifting etc. The tranny was operating normally AS FAR AS I CAN REMEMBER. The last time I drove a 240D was in 1990. So I was not 100% sure.
I called the tranny shop and lied a little. Told him I was stuck in Chicago on a trip.
Drove the car to the local Mercedes dealer. They had a Technition drive the car and I went with him. He said the transmission was shifting fine. Up shift and down shift. No flair, no problems.
I then let the Service Advisor that I know and trust there, drive it also. He has a 240D. He said it was fine.
Soooo it looks like all the problems were a vacuum system problem. The vacuum system was in bad shape. Door leaks, deteriorated rubber 3 and 4 ways, and straight connectors.
Its nice to know that we probably save the $1100 + tax that we were going to spend.
I will continue to detail the vacuum system and get the car up to 100%.

Just had to share my $1100 savings with you guys.

I'm going to tell the tranny guy what I have learned. I would hate to find out we do need a tranny within 3 months to a year. The tansmission shop seamed very good so I don't want to burn that bridge. But then again his shop was the one who test drove the car for the guy I bought it from and said it needed rebuilding!!!
I need to drive the car regularly and hard to get a true feel for the cars condition.

Also the left guide rod mount gave me a few creaks and growns while driving so I wll replace them. They were not replace in the front end rebuild.

Dave

[Rick Miley]

I love it!
That's fantastic news, Dave. Hope your daughter likes the new car and appreciates all the effort you put into it.

Got any Tampa layovers coming up? My 240 would love to see you.

[Fisherman]

I do not believe that this would be indicative of a failing vacuum pump. The normal location for the oil contamination would be the vacuum line leading to the intake not the other way around. With the system applying vacuum to that line I think this is indicative of a failing mastr cylinder. It would then leak into the booster can and then get pulled into the vacuum pump.

I just happened to notice this and may be wrong on the diagnosis but if the line going to the air intake doesn't have oil in it then the vacuum pump may be fine.

[dmorrison]

Rick
Sorry I don't do layovers anymore. After flying worldwide in the military and domestically with American. I got real tired of the hotels and all the crap associated with them.
I just do turns now, fly out to a city and turn around and fly home in the same day. Instead of flying the 767 internationally or the 777 internationally, I fly the MD 80 domestically. I'm pretty senior on the aircraft so I just fly turns. Usually to the west coast. SFO, SAN or SJC. This way when I fly I get a lot of hours per day, which means less days of work for the month. And when I return from the turn I've usually flown 7.2 to 7.5 hours. I cannot be used for anything but the drive home (8 hours of flying in the air per day is a maximum set by the FAA). I'm getting to be one of those senior guys that the junior guys want to retire. But I have 10.5 more years.

Fisherman.
To my knowledge, and I could be wrong, wouldn't be the first time. On the 240D and 300D/CD/TD, with slight variations in each model. The vacuum pump pulls vacuum but over the many miles of driving the diaphram in the vacuum pump, or piston seal in the piston type, can fail and allow oil to slowly move into the vacuum system. Since a vacuum remains on the system once the engine is turned off, the oil in the vacuum pump, that is getting past the diaphram/piston seal, is slowly sucked into the lines of the system.
Additionally the vacuum shutoff in the injection pump can allow oil to get into the vacuum tubes the same way.
On the 240D in 1983 the vacuum system is NOT connected to the intake manifold ( I'm positive, I just looked). So oil cannot enter this way. The connection simply does not exist on the 83 240D. Now on my 82 300TD and my 86 300SDL the vacuum system IS connected to the intake manifold. I figured the engineers at Mercedes realized that the poor 240D has absolutely no power as it is, so for God's sake, don't steel anything fom the intake. Just my thoughts!!!
The brake booster is a possible entry point for the oil, or in this case brake fluid which by the time it enters the lines would probably be black and look like oil. I will check the booster when I remove the booster/master cylinder to install the swaybar mount bushings. At that time I will replace the Oring to the master cylinder and check the MS for leaks. Is the master cylinder leaking? I have not had the car long enough to determine that by observing the fluid level. Actually I just replaced the brake reservoir to master cylinder orings. They were leaking. I will check the MS when I remove the booster.

Thanks for the input.

Dave

[Rick Miley]

Earlier 240Ds (including mine) have the clear vacuum exhaust tube to the intake. They changed the pump later on to exhaust into the crankcase, eliminating the need for the tube.

Did you check for oil in the key switch or shutoff line? Maybe the shutoff leaked and everything wasn't cleaned up properly when they fixed it. Or maybe it still leaks - how well does it shut down?

[dmorrison]

Rick
I have not physically looked at the ignition switch shutoff valve. but both lines going to and from the valve do not have oil in them. Since isolating the door element and replacing all the bad rubber the car operates fine. Brakes, shutoff, remaining door elements and transmission.
The amount of oil in the vacuum pump to brake booster line was very small. I have seen cars where the lines are all black and a lot of oil is in the vacuum system. This car is not in that shape. Since my Daughter cannot take the car to Texas A&M until the Fall semester. I have time to get the car up to 100%. That way I won't have to worry about any of the systems. Plus this summer she will have to get greasy and sweat a little on her car. She will, I know that. 5 years ago when I rebuilt the driveshaft to my 300TD she was right there under the car with me. She's actually looking forward to working on her car. Our deal is that we can split the cost of a car but they have to pay for all the maintenance and diesel. This way they have so much sweat equity into the car they don't want to wreck it. It really worked with my sons 65 Mustang Fastback. He really babys the car.

Dave

[Fisherman]

I love this board...
You learn something new every day here.
dmorrison, I had not considered the leak back into the system after shutoff but makes perfect sense. Thanks for the insight!

[maniacal]

I thought about starting a new thread, but this one seemed appropritae so I will just chime in here.

I have just purchased this car, E-bay item# 2455960114 , an '83 240D automatic.

It seems to be in reasonably good shape, no rust or major dings, and it does start every time. But it is a real dog when it is cold, and only slightly less canine when it warms up. I very much appreciate this thread. I have some of the same problems with shifting, in which I have to completely lift off to get a shift into the highest gear, especially when it is cold. I plan to take it into a local mechanic that was recommended to me by a friend with an '85 300SD.

Anyway, this looks like a very informative board and I plan to lurk a lot and sponge up whatever knowledge I can.

By way of introduction, I am a mechanical engineer, and not ignorant about things mechanical, but I am very ignorant (but not stupid) about things diesel. CV: BSME, MSME BYU '87,92, worked in the skunk works at lockheed, then in japan for 18 months now working for flextronics design in San Diego (OK, Valley Center)

Thanks

Chris Stratford

[Fisherman]

Hey Chris,
Welcome to the board. hard shifting in these cars is often caused by a lack of vacuum to the trans modulator. Too much vacuum on the other hand makes them really soft.

At the bottom of the forum is a search function that can be used with standard boolean logic i.e AND, OR, etc...
It works quite well and is a great resource for new members. On the transmission issue you can search for hard shift or upshift or the slipping that folks get is called flaring by most here.

Anyway, a search on this subject will provide you with a lot of light reading...

[dmorrison]

maniacal
Welcome to the forum.
First go to this site and learn about your car. This site is for a 300D you have the 240D. Body will be the same ingeneral. But the engine stuff will be different.
Mercedes tends to follow the same ideas from one car to another. So this is a place to start.

http://skinnerbox.steaky.org/123_DISK2/program/123-cd-index.html

Read up on the vacuum system. That will cover, door locks, trunk lock, fuel door lock. Air conditioning elements (your car will have just 2), Injector pump shutoff, Brake booster, transmission shifting sensor, vacuum pump, and airswitch valves on the valve cover(under the black plastic cover) for your EGR valve.

To make sure your transmission is the problem and not the vacuum system. Check or replace all the rubber connections. The straight pieces, the 3 way pieces and the 4 way paices. Buy a Mityvac vacuum pump, This will help you check the system.

http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=2068

Then start checking the various elements on the vacuum system.
If the vacuum system is sound and the tranny still gives you problems then we will look at the transmission. Adjustments can be made to the transmission.
1980-1983 Mercedes transmissions were known for needing a rebuild after about 100,000mi. So you may be at that point.
Keep us posted

Dave

PS "worked in the skunk works at lockheed" Your obviously over qualified to work on diesels. They are a primative engine. So you have to think on a more basic level.

[dmorrison]

Worked on the car a little today. Removed the fuel sending unit and opened it up. Covered with algae. Cleaned the unit with carb cleaner and checked ite function with the guage. Seems to wotk correctly. But no reserve light. I'll have to check that. Coudl be the bulb. It does not test when the key is turned on nor when the tank sender is in the contact position. Cleaned the contacts thouroughly.

Will probably remove the tank and pressure wash it. Otherwise I'll be playing the filter changing game.

Went to the dealer to get some info on the throttle linkage. It took him 45 mins to find my cars pictures. It shows as a 240D manual transmission, not the auto it came with. so I finally have a exploded view of the throttle linkage. The SM did not cover my setup. I will order the plastic bushing parts of the throttle linkage.

The door locks will not unlock after 30 mins or so. I must ahve another element lock that I did not find. I will probably replace all the rubber boots in the elements. George Murphy sells just the rubber diaphram for $5.00 So I'll rebuild the 3 door elements and replace the fule door and trunk element as well as the 3 and 4 ways inside the car.

Dave

[83MB240D]

Very good info Dave! Keep up the informative posts.