190D 2.5T 5-speed Funny clutch/pressure plate/throwout/cylinder issue??? - PeachParts Mercedes-Benz Forum

Jetmugg · #1 06-04-2012, 10:37 AM

I've been away from the board for a while, but my Benz hasn't had any issues for quite a while. The car is '93 190-series, which has a transplanted OM602 2.5Turbo engine, and a "diesel spec" 5-speed from an '85 190D. This has been an extremely trouble-free, enjoyable car to drive since I put it together (about 60K miles ago). I put a clutch disk, pressure plate, and throwout bearing in the car roughly 30K ago. Before that, I was using the junkyard setup from the trans I pulled from the 'yard, before investing in a completely fresh setup.

The shifting has always been silky-smooth, up until a couple of months ago. Since then, I have an occasional problem with "something" not releasing in the clutch/throwout/master/slave system. When it acts up, the shifting will become extremely stiff, not wanting to go into gear. This most often happens after I've been driving a while, pull off an interstate exit ramp, etc. When I go to shift back into 1st or 2nd, it's almost impossible to get into gear. Then, just like magic, poof - it frees up and drives fine until the next episode, which might be several days apart. I think it's getting worse lately.

Another sign that there is trouble is that occasionally, when I go to start it, with the clutch depressed, the car will start to move when the engine fires.

It seems to me that the clutch disk is not fully releasing from the flywheel and/or pressure plate when this problem occurs. The main things I think could be the root cause would be the clutch disk sticking on the input shaft splines, or the throwout bearing sticking on the sleeve on the front of the trans, or possibly the slave cylinder not extending fully.

The car does not leak any brake/clutch fluid, so I believe the master and slave are OK.

I know that what I'll have to do is pull the trans to get a look at the clutch area and try to figure out if anything looks bad or worn. I'm not looking forward to this job, but I don't see any other way around it.

What I'm hoping to get from this post is some feedback from any others who might have had a similar issue in the past, and what the root cause was in their case.

Any feedback or other brainstorming ideas would be appreciated.

Steve M.

t walgamuth · #2 06-04-2012, 11:25 AM

sounds like a hydraulic clutch issue. does pumping the clutch assist getting it into gear?

ah-kay · #3 06-04-2012, 11:26 AM

I have nothing to offer except my experience with my 190D 5sp 6 weeks ago. It started with difficulties getting into 1st and 2nd gear. It wasn't felt right but it would eventually shift. One day the clutch went after driving 50 miles on the freeway. No clutch at the exit ramp but managed to limp home by starting in gear. When at home, the clutch came back. Bled the clutch and everything seemed fine. ( I changed the brake MC 2 months back but it should not be related. ) Drove the car for a week and everything seemed OK. Took the car for a trip to San Francisco and no clutch again after about 100 miles. Stranded in LA and limped home again by starting in gear. This time the clutch did not come back and had been in the garage for 3 weeks while I was on vacation.

I suspect is the clutch hydraulics so I changed the clutch master cylinder last night. What a PITA job. Will change out the slave cyl this week and hopefully have the car back on the road this w/e. Your problem may also by the clutch hydraulic but you will be the judge.

Good luck.

Jetmugg · #4 06-04-2012, 12:03 PM

This sounds encouraging. At first, I thought that maybe it was a hydraulic issue, but since the problem is pretty infrequent, I couldn't explain that in terms of the hydraulics.

The good news is that replacing either the master or slave cylinders will not require complete removal of the trans (although changing the slave in the car is still a PITA).

Any ideas on how to determine whether the master or the slave cylinder might the the culprit?

Steve.

Walkenvol · #5 06-04-2012, 12:33 PM

Can't offer any help on your current problem other than I'd fully eliminate the clutch hydralic system prior to pulling the trans if it were mine.

Question - what did you do for a drive shaft with the 5-speed in the 300?

Jetmugg · #6 06-04-2012, 02:36 PM

I don't have a 300-series car with a 5-speed setup. All my manual trans cars are/were W201's. There are some guys with W124 (300 series) 5-speed setups, though. There were 300E's available with manual transmissions. Those could be used as driveshaft donors, or you could pay the dealership price for the correct shaft.

T-walgamuth- sometimes rapid pumping of the clutch pedal will revive the shifting. I couldn't decide for myself whether this was due to hydraulic issues, or if something (throwout bearing?) was sticking, and pumping the pedal would break it loose.

Steve.

Jetmugg · #7 06-04-2012, 02:38 PM

I think that the smart thing to do will be to replace the master and slave at the same time. I only want to bleed this system once, as you all know, it's not a fun job. I do have a pressurized power bleeder, but it still has the potential for a big mess and a brake fluid shower.

ah-kay · #8 06-04-2012, 02:45 PM

Quote:

Originally Posted by Jetmugg

I think that the smart thing to do will be to replace the master and slave at the same time. I only want to bleed this system once, as you all know, it's not a fun job. I do have a pressurized power bleeder, but it still has the potential for a big mess and a brake fluid shower.

I am not sure whether a power bleeder will help as clutch bleeding is a different animal. It need to be bled from below, at the slave cylinder. Let me know if you know of a better method as I will be tackling this job sometimes this week. I replace both cylinders as they are not that expensive.

Jetmugg · #9 06-04-2012, 03:03 PM

I have bled these systems a couple of times in the past. I use the pressure bleeder from the bottom, just hooking the output hose of the bleeder to the bleeder valve on the slave cylinder.

The tricky part is getting the hose attachment secure, while still being able to loosen/tighten the bleeder valve, while at the same time not blowing the hose off the end of the valve and giving youself a brake fluid shower while laying underneath the car.

It's a delicate balancing act.

Air&Road · #10 06-04-2012, 03:32 PM

It is indeed most likely a hydraulic issue, HOWEVER, I've seen pressure plate fingers break and float around causing the clutch to intermittently not release.

If you go through a thorough hydraulic troubleshooting process and find everything good. Pull the transmission and inspect the pressure plate, et al.

Hope this helps.

Jetmugg · #11 06-04-2012, 03:49 PM

Hydraulics it is, then. Looking through Fastlane, it appears that the part# for the slave cylinder changed at some point during the W201 years. Any idea when and why there is more than 1 slave cylinder available?

Steve.

Jetmugg · #12 06-18-2012, 08:50 AM

I replaced the master and slave cylinders, and wanted to change the combination hard/soft hydraulic line as well. The line really wasn't "bad", but since I had it out, I thought it would be a good idea to replace it. I couldn't come up with a replacement hard/soft hydraulic line, however. The local hydraulic shop couldn't make one, and this part seems pretty much a crapshoot from the dealer ($170 for both pieces, with no guarantee that it was the correct part).

Anyway, the clutch operates great now, with the pedal in the middle of the range. The original slave cylinder shaft (250,000 miles), had a noticeable amount of wear on the ball-shaped end.

While I was under there, I changed the ATF in the gearbox as well. Smooth shifting and smooth clutch operation make it like driving a new car again.

Steve.