a few questions about my 1983 300sd - PeachParts Mercedes-Benz Forum

#1 08-08-2002, 01:21 AM

hi everyone. i recently got a 1983 300sd with 183,000 miles on it. i have a bunch of questions because a bunch of little things need to be fixed, but maybe i'll only get into a few things now.

first- is there anywhere to get a parts number list for this car? perhaps with a diagram, so that i can see what needs replacing and then just note the part number? because i don't have anything like this and i only know so many technical names for parts, i have to describe the parts the best i can.

the black plastic elbow tube that connects to where the air filter is (this tube is probably about 3" in diameter, its not a little tube)- it has a crack in it. it needs to be replaced. the engine raddles a bit when its idling because of this. once given any gas, it stops immediately because there is enough suction to pull the crack closed. anyway, i don't know what the part number is or what that piece of plactic tubing is called- can anyone help??

i have never owned a diesel car before, but i am concerned about the spots the car leaves on the driveway after being parked for a bit. there is a little bit of oil, but it seems like fuel is leaking too? it is not oil- and when i bend down to smell it- it smells like diesel fuel- but that may just be coincidence. but whatever that is, it is leaking much more than the little spot of oil the car leaves. i really don't think it has an oil leak. its this other stuff that concerns me. maybe this is normal for a diesel car, but i wouldn't know- i've only had this one for a few weeks. any ideas? could these two problems (if the second is a problem) be related?

other things that need attention are:
cruise control doens't work
power locks don't work (previous owner cut(?) line [in trunk])
both driver and passenger seat don't move up and down- power seats work fine every other way. you can hear the motor when you push the lever to have the seat move up or down- but the seats don't move.
vacuum modulator needs adjusting (sticking 2nd gear)

i have no idea how much any of this stuff costs to fix. maybe the problems are being caused by something small- but i wouldn't really know.

thanks for all the help regarding the things i mentioned.

nick

RG5384 · #2 08-08-2002, 02:03 AM

being an owner of an 83 300SD i can help you out with a couple of your problems.
With reguard to that black plastic "elbow", it is called a breather tube and there is an updated one, i dont think they are more than ten dollars. However, this should not be causing your rattling. Check to see if your air cleaner mount is securely attached, there are three rubber air cleaner bracket mounts that have a tendency to break. They cost 1.60 each i beleive but the breather tube alone will not cause the car to rattle. The cruise control is more than likely the cruise amp, located under the driver's side kick pannel. I think it runs around 200$ and there is a series of test to do first to see if that really is your problem. With reguard to the power locks, the most likely reason the pump has been "take out of the loop" is because of a leaky diaphram. You will need to rent a miti-vac or some other vacuum pulling guage to seewhere your leaks are. THe diaphrams are located in each of the doors, one in the trunk, and one for the gas filler flap. On the oil leak issue, i have not known one diesel owner who can honestly say thier diesel doesn't leak oil. On the fuel issue, it is most likely a cracked fuel return line, look around the injectors and see if you see fuel dripping while it is running. THese lines turn brittle with age and will crack and leak. This is a very simply fix and a very easy DIY. Sorry but i can't help you on the tranny issue. You can find tons of information on all of these issues by using the search function. Good luck and welcome to mercedesshop!!
Ryan

RSH · #3 08-08-2002, 03:48 AM

#1 You can buy a manual for your car to help with parts identification, ebay is a easy place to buy one, the manuals come on CD's and run anywhere from $10.00 on up. #2. The tube that connects to the air cleaner housing is the intake hose even if its cracked it is not the reason the air cleaner assembly rattles, grab the metal housing itself and see if it moves, if it does chances are the air cleaner mount or the rubber bonded metal shock absorbers are bad or a combination of both and will have to be replaced. #3 Old cars can leak a little, Mercedes is not excluded, you will have to get under the car to determine where it is leaking from, it is best to start off with a clean motor and under carriage then it will be easier to find the leak or leaks and also decide if its something reasonable like a fuel or oil line, pan gasket or something more difficult like a motor or trans seal. #4 Diesel fuel leakage, check all the fuel lines and around the the pump and injectors for moisture (fuel) replace hoses and tighten fittings as required. #5 power locks, what line did the previous owner cut vacuum or electrical?, in the trunk next to the spare tire is the vacuum pump for the door locks does it operate? if so find where the vacuum line is cut and repair it, maybe the locks will operate. #6 power seats, at least the motors operate, so that takes the motors and switches out of the loop, the seats have drive cables from the motors to gear drives, early Mercedes sometimes have drive cables that were to short from the factory, you have a few options, buy and install new drive cables, modify the drive cable housing for the non operating mode (up/down), I have had good luck with disconnecting the cable from the motor side and sliding the shaft inside to re-engage the gear drive, which on the last one i've done has been operational over a year now, or you can leave it non operational, btw i did not have to remove the seats to fix that problem, only remove the four bolts holding the seat and tip it back. #7 tranny problem? are you sure its the modulator? check and renew all vacuum lines as needed, it doesn't have to be much of a leak to effect motor or tranny operation also has the tranny been serviced lately? #8 cruise control, it could be simple like a loose or corroded connection or fuse, sometimes accessories that share a fuse will operate and others will not, then you replace the fuse and everything works, it could be the cruise control amplifier (more difficult) either rebuild or replace, there is one on ebay now for less than $25.00 last time I checked. You have enough to keep you or someone busy for a few weekends, good luck and welcome to the board, alot of knowlege is here, just ask or do a search.

the_good_fellow · #4 08-08-2002, 12:21 PM

Quote:

the black plastic elbow tube that connects to where the air filter is (this tube is probably about 3" in diameter, its not a little tube

I think he is talking about the one from air filter hosing to turbo charger.

RG5384 · #5 08-08-2002, 12:28 PM

ahh i just now read the 3" in diameter part. yes, that would not be the breather hose. Which part of the air filter does it attach to?
Ryan

#6 08-08-2002, 01:11 PM

The three inch tube plugs into the snout in the front of the air cleaner.
I doubt that would rattle much. Seems like if it did a little duct tape would quiet it until a replacement could be found.
The usual suspect with this is the air cleaner canister rattling against the valve cover. There is a very tight gap between the two. Some have has success with drillling a hole into the housing and using a broken mount from under the housing. You can just intall it on the side of the canister where it rattles against the valve cover. Takes a small metric nut to fasten it. I used some weatherstripping to stop the rattle. So far, so good.

RG5384 · #7 08-08-2002, 02:16 PM

i'm trying to figure out if he's talking about the 3" tube that goes to the front of the engine compartment or the 3"tube that connects the turbo to the air filter. If it's that tube, it should be fixed ASAP(even if all you do is put duct tape over it as a temp fix) as any little dirt can destroy a turbo in short order.
Ryan

#8 08-08-2002, 02:19 PM

Do you mean the U shaped tube? No doubt that would cause trouble if it was cracked open. Best to replace it, until then.. the handymans secret weapon... Duct tape.

RG5384 · #9 08-08-2002, 02:23 PM

if it can't be fixed with a little duct tape, super glue, and twisty ties it's FUBAR! lol
R

GR_Lou · #10 08-11-2002, 12:57 PM

Cruise control...this worked for me!

My '83 had a non-working tach and cruise. I used the "cigarette butt" trick (do a search) and the tach worked.

I also did the BB trick (actually used a golf tee) on the EGR valve.

Between these two fixes, both started working. Maybe I just chased a gremlin away, maybe they're somewhat related. The tach is starting to go on/off.

Also, the pass. rear window doesn't work, and the passenger rear stopped also. Tore the panel off the door, got frustrated, another "work in progress".

psfred · #11 08-11-2002, 01:23 PM

Nick:

The rattle is most likely the air cleaner housing loose. Typical, easy fix.

The fuel leak is almost certainly the overflow lines. The run between the injectors and back to the fuel return line, drivers side of the engine, black braid covered rubber, about 1/4" in diameter. Get MB replacements (from the dealer or a good indy shop) as nothing else you will find, unless it really is 1/8" ID fuel line, will hold up. They get old and crack where they fit on the injectors, and dribble fuel. It mostly evaporates while you are driving, but will leak enough with the engine cold to drip. Ruins you fuel milage, too!

When you get new ones, use a pair of needle-nosed plier to remove the old ones by gripping at the base beside the nipple they are shoved onto and "tearing" them by crushing JUST the rubber -- they won't come off intact by pulling, most of the time. Make sure you don't scratch or bend the nipple. Keep the little plug in the rearmost one (only 1' long or so) and put it into the short bit you got new.

To install the new hoses, grasp them with the needlenosed pliers, leaving just enough sticking out past the jaws to cover the nipple, and push down firmly over the nipple. The hose must seat against the base of the nipple, or it will tend to slide back off.

Easier done than described. You will find them all to be cracked and covered with fuel.

The CC is indeed the amplifier -- but check to make sure both brake lights work properly, too -- the CC amp grounds through the brake lamp filaments, and if one is bad, it won't work.

For the locks, there is a single pump in the trunk -- produces vac to lock and pressure to unlock. If one of the hard plastic lines is cut, try splicing it with a small piece of rubber hose from the autoparts store. Be aware that someone may have cut it because the locking system was malfunctioning, leaving the doors locked all the time, or keeping the fuel filler door locked. You can test it by having someone operate one of the front door lock buttons while you check for vac and pressure at the trunk lock line. If the pump is toast, get one from the junk yard, they are cheaper.

The hard shift on the tranny could very well be a vacuum problem -- they are vac modulated via valving system. On the injection pump there is a little aluminum box with vacuum lines attached. You can ignore the black one, it is a vent, but check all the other ones for the condition of the rubber connectors. If these are cracked, mushy, or rock hard, they are leaking, and if you have no vac, the tranny will shift late and hard, hanging at low throttle.

You will also need to check the bowden cable -- should be pulled all the way out with just enough pressure on the spring to keep it from rattling at full throttle. I don't have one of these, so I can't tell you where it is, except that it is on the throttle linkage somewhere.

Hope this helps -- if the oil was changed properly, you should be enjoying this car for another 10 years or so!

Peter

Wallknight · #12 08-12-2002, 04:44 PM

Hey redhdeight:
Welcome aboard. It seems your sd and my 300D were in about the same shape: tons of little problems. Just stay close to this discussion board and do lots of searches. Above all, have fun and dont let it frustrate you. Chances are, everything has a cheap and easy fix; Its a MB after all!!