Need help! my Clutch is locked up!?!?
 

Car is a 1971 220 with a low mileage 230.4 engine, installed less than a year ago. New clutch, pressure plate, new throw out bearing, new slave cylinder. Last November the starter motor shorted. I didn't find time or clear dry weather until last weekend to replace the starter, now a new Bosch resides in the car and it starts fine. But I am at my wits end because the clutch will not disengage!
I figured it might be the clutch master cylinder, so I replaced the brake reservoir (the top to one level sensor was cracked) - hey I needed to bleed the brakes at the same time - so I did that, THEN I installed a new clutch master, bled the line umpteen times, including a pressure bleed back from the slave cylinder, all to no avail. I cannot disengage the clutch! I do not believe it is air in the line as many times as I have bled the clutch.
Can a clutch get stuck like this in only two months? I heard someone say after years of sitting a clutch can rust frozen, and a soultion is to start the car in gear and run it fast and hard in 1st gear then let it decelerate by pumping the throttle, so I just did that. Let me tell you that was a lot of fun, sorta like a bucking bronco (no I never did ride a bull actually!) but it had no effect whatsoever on the still locked up clutch!
Any hints from those that know what the heck might be going on?
One clue, it has been very wet and rainy the whole period since last November. Could the pressure plate be rusted stuck to the flywheel???
This car ran like a top before I let it go sit.
Booo Hooo! :( I like the lil bugger (and suddenly I need it while I work on the only other car I have available, we gots lots of daily drivers here!)
Dieseldiehard
1971 220 (gas) 4-spd manual 104041
1979 300TD w/ ’85 turbo engine 289560
1983 300D 237490
1985 300TD 206150
1975 300D (looking for an engine)
1987 300D 250K newest addition

Yup, sounds exactly like the clutch plate is rusted to the flywheel.

You have to do the bronco thing with the clutch pedal down, though, or nothing happens!

I remember rocking my brother's Rabbit in the parking lot after it sat for a winter with bad ignition points. Got buried in snow and salt, what a mess.

Get some beefy buds to help -- put the lightest one in the car and put it in first or reverse, and have him or her hold the clutch pedal in. The rest of you get to alternately shove the car back and forth!

Check to make sure the slave cylinder is extending, too -- it's possible it blew a seal, after all, and you are just pumping brake fluid on the ground.

Peter

I had that happen on an old diesel I had. Deep water doesn't bother the engine but I never thought about the clutch. I tried the bucking bronco trick too but had the same success. What worked for me was using the starter, hitting the starter with it in gear and the clutch in broke it loose. Granted the diesel starter is bigger, but the initial torque and shock would be more than a bucking bronco.

Funny you should mention that now, that just happened to my wife's car. She said it made a "funny sound" then the clutch stopped working. It had been making "funny sounds" from the bell housing for a little while, like something was rattling around. I figured the clutch was near the end of its life anyway (180,000 miles.) When I took it apart the clutch disc had some missing pieces and the pressure plate springs were banged up. All new parts and its running good, but different, now.

OK, thanks for the confirmation.
I need a tool to check for slave extension.
I plan to try the bucking bronco bit again. I did have the clutch depressed when I tried it in first gear. darnedest thing!
DDH

What actually happens when you push the clutch pedal in? Does it feel like a normal clutch? Or does it not move at all? I am having a hard time visualizing how the pressure plate could rust to the flywheel when it has the disk in between.

Pressing the clutch one feels normal resistance, its just that the pressure plate doesn't disengage.
After speaking with HGV and others, I now believe that the pilot bearing may be frozen to the input shaft, further investigation will be forthcoming after a look see, meaning pulling the tranny:mad:
DDH.

Thats exactly what my two instances did. If you feel normal resistance it is the pressure plate springs you feel, it is disengaging. The clutch disc "floats" when disengeged, nothing actually stops is. It doesn't take much force to "sink" it, a little rust or small piece or metal. I've heard noisy ones you could hear spool down when the clutch is disengeged, it takes a second or so.

The throwout bearing is between the spinning (with the flywheel)pressure plate and the actuation arm (not spinning.) If the throwout bearing seized, it would be real obvious.

You could also try temperature cycling it. Let it get warm, run it (or drive it if you know how) 20 minutes or more, and let it cool.

If I may suggest again, try the starter. Even a gas one has lots of power. They have enough to bend valves if the cam is in the wrong place.:eek:

What if you got it going and then hit the emergency brake to stop the rear wheels while the engine is running, in gear? That ought to break it loose. You could do that with the car jacked up.

My frined who operated a transmission shop for years advised against further bucking bronco type actions. He saw too many gouged transmission input shafts. If it gets badly scored it won't be easy to fix.
As an interesting side note, he said some mechanics left off the engine grounding strap, and the starter current eroded the transmission shaft, that is the return path for current if the engine block isn't grounded (at least in the particular types of cars he was asked to repair). A badly eroded shaft will never last long, it eats the bearings, especially if the pilot bearing is made of phosphor bronze. OTOH, a properly greased bronze bearing will outlast a needle bearing according to his experience.

My car is being towed back to the shop that installed the clutch parts. If we find no grease on the bearings, discussions will turn to a warranty matter (the individual that did the work is now gone, fortunately).
I also am replacing the differential, so its is going to be up on a lift for a while as the problem unravels. I'll post the outcome here later.
DDH

I am having an even harder time believing that the polished metal of the input shaft tip, the pilot bushing, and the crank hub could somehow fuse themselves together to the point where the force of the engine could not break it loose. But I will keep an open mind and eagerly await your findings!

I've never seen a pilot bushing seize to the input shaft but I've seen clutch discs (two of them on Mercedes) rust to the pressure plate and/or flywheel. After several months disuse in a damp climate, and with a normal pedal action and feel, that's the most likely cause.

Happy Motoring, Mark

I've seen clutch discs (two of them on Mercedes) rust to the pressure plate
 

I suspected this until I looked at a clutch disc, it has friction material in contact with the flywheel, how can that rust ? I guess I don't understand this whole thing completely. Will soon find out though.
The key word here is DAMP CLIMATE, that is exactly the condition that we have had in No..Calif. - rain on and off for two months. It is coming down in buckets this morning! Rust has to be the problem!:mad:
DDH

The disc material won't rust but the pressure plate and flywheel will. The rust mingles with and grips the friction material, much like a rusty can sticks to a damp piece of cardboard over time. Sometimes you can break the clutch loose if you hold the clutch pedal down and try to start it or drive it with the brake applied. Otherwise you'll have to go ahead and pull the trans to separate pressure plate, disc and flywheel.

Some recommend to block the clutch pedal or fork in the released position if the vehicle won't be driven for awhile, though this might be hard on the pressure plate spring.

Happy Motoring, Mark

Greasing splines where clutch disc slides is controversial among mechanics.... some use graphite dust instead of grease thinking the dust wont sling off and slime the disc - others use NO grease at all - even worse they remove existing grease from the spline and assemble it 'dry'.

If rust has frozen the disc to the flywheel, you can bet the disc/spline is participating with the problem....... you might have to bite the bullet and drop the tranny to free it up.

Or if it was me, I'd first be crawling underneath with can of WD-40..... shooting penetrating oil through spicket attachent on aerosol can through bell-housing weep hole underneath - litterally soaking as much of the clutch as i can reach, knowing that penetrating oil will evaporate with little residue - so not to slime the disc pads.

Problem Solved!
 

Mark was correct, it was the pressure plate/clutch disc rusted to the flywheel surface.
The trans was pulled and a long prybar used to free things up.
I still am amazed at how quicky all this occurred, it happened in less than 60 days. At least one third of those days were rainy ones with high humidity in between.
LESSON LEARNED:p
That is what I got for not garaging the car. I will try to avoid this by operating the car frequently from now on, and if my starter motor ever fails again (knock on wood) I'll be sure to fix it right away.
As a side note, while it was up on the lift, I had a 3.07 differential (out of a 300D turbo) put in place of the 3.46 unit yesterday.
The car really is a nice runner now, the 4-banger was wound up pretty tight at 75 MPH before this, now it likes to cruise at those speeds!
I have a small VDO Tach to install on the dash but I am waiting for nice weather and some warm day I'll replace the dash with one that came out of a 1976 300D - I'll welcome the addition of some wood as well as NO CRACKS!
DDH