1980 240D Clutch went out.....

[wordmanjay]

Pushed the clutch in- very loose- comes back up, but not like it did.
Doesn't engage clutch.
I've never fixed a clutch problem.
Where to begin?
Please help.
Thanks.
Jay

[Biodiesel300TD]

Sounds like a hydraulic problem. Either low fluid or a bad master or slave cylinder. The fluid is shared with the brake fluid, so check that first. The reservoir is two chambered so make sure both chambers are full. Then I would look at the master cylinder which in behind the clutch petal. Look for leaks, and also inspect the slave, it's on the trans.

[JimSmith]

Originally Posted by Biodiesel300TD

Sounds like a hydraulic problem. Either low fluid or a bad master or slave cylinder. The fluid is shared with the brake fluid, so check that first. The reservoir is two chambered so make sure both chambers are full. Then I would look at the master cylinder which in behind the clutch petal. Look for leaks, and also inspect the slave, it's on the trans.

Biodiesel300TD is right. Check the level of the aft chamber in the brake fluid reservoir. If it is below the little fitting with the rubber hose connection on the outboard side (I believe), that means you have a leak in the clutch hydraulic system and the fluid has leaked down to the level where the brakes remain unaffected, but the reservoir no longer tops off the clutch hydraulic system. If you find the level down to that point, pull the carpets back under the clutch pedal and look for evidence of leaking brake fluid. If you find evidence of leaking brake fluid you need to remove it as the stuff is not good for paint and will therefore lead to exposing your floor boards to water or worse. Meaning corrosion will begin in earnest. Remove it by wetting the area with water and then wiping up the residue. Do it a couple of times. If the stuff is on the carpet, soak the carpet in water. Water will neutralize the brake fluid as it is absorbed into the brake fluid.

If there is a leak in one of these cylinders the other will begin to leak soon so I highly recommend you replace both of them and get the pain over with - they fail because no one changes out the fluid (it is in a kind of "dead end" system and the slave cylinder is difficult to reach for most of us, or the fact that the fluid might need to be changes is not always apparent) and it gets contaminated with water, leading to corrosion products being generated that abrade the seals. In all likelihood if one has been damaged by corrosion products in the fluid the other is well on its way.

If the problem is not the fluid leaking, and is actually the clutch worn out, the job is not quite so simple. You will need to drop the transmission and remove the clutch parts. I have replaced a few of these, never because they wore out, but once because the pressure plate springs failed due to oil leaking onto the clutch from the rear crank seal, causing some violent chattering and once because the ring gear and starter pinion became disagreeable and the ring gear got chewed up to the point where the starter would not engage. So, to replace the ring gear you have to get to the flywheel and I was reluctant to reinstall a clutch that had over 200k miles on it. Typically the pressure plate only needs to replaced if it is abused. But the clutch plate is a wear item, as is the throw out bearing. They always need to be replaced when you remove them because the clutch is worn.

Jim

[Skippy]

For the most part, I agree with everything JimSmith said. The only exception is that I replaced the slave cylinder on my 240D right after I bought it in 2006, and left the master cylinder. I haven't had any issues with it to date.

Edit: Oops. JimSmith, not JimB.

[fruitcakesa]

Can a slave cylinder fail and have no external fluid loss?

[layback40]

If no fluid leaking around slave then it sounds more like the master.If you are doing the master , best do the slave as well.

[Skippy]

Originally Posted by fruitcakesa

Can a slave cylinder fail and have no external fluid loss?

I don't think so. A master cylinder can fail without an external leak, because no pressure gets created. The slave cylinder gets fed pressure and it has to go somewhere.