Thread: Clutch slipping

Originally Posted by fender22

Just had my slave cylinder done (completely blew) and notice now I have a bit of clutch slip...mainly in 3rd and 4th. Was doing it a bit before hand too but seems worse now. I figured the slave must have been leaking slowly into the housing before it completely gave way but does seem worse now.
I spoke to the mechanic and told him about the drain plug in the bell housing. Would that be the cause? Is it also possible for oil to leak back from the engine onto the clutch?

Oil on the clutch will cause it to slip, either brake fluid from the slave cylinder or oil from the engine, but so will wear on the clutch. It is also possible (although unlikely) that the slave cylinder replacement is incorrect and is applying pressure to the release bearing all the time. Although it should not have been messed with when doing the slave cylinder, incorrect adjustment of the pushrod on the master cylinder can have the same effect.

John

New clutch a year ago so shouldn't be wear. I am concerned though maybe it is engine oil although there is no leaks but I guess it stays in the housing? If it was engine oil would that be from the main rear seal? Is that expensive?

Originally Posted by fender22

New clutch a year ago so shouldn't be wear. I am concerned though maybe it is engine oil although there is no leaks but I guess it stays in the housing? If it was engine oil would that be from the main rear seal? Is that expensive?

Unless the flywheel housing drain plug is removed, yes, it stays there, although usually there will be some signs of oil.

You have not said what engine you have, but the rear main seal will be fairly cheap - however, replacing it almost certainly means either engine or gearbox out, which is a fair bit of work or labor for a start.

Since the problem seems to have started with the slave cylinder replacement, I would look there first. Check that the clutch pedal has at least a centimetre of free play before it starts moving anything. If it does not, your problem is most likely, as I commented, incorrect slave cylinder.

John

Per my first post, it was doing it to a lesser extent before the slave cylinder went. mechanic came and had another look this morning and removed the plug and said there was in fact a good desert spoon or two of brake oil in there. he also indicated that the save cylinder would have been leaking to some extent in the months up to when it completely went hence issue before. He reckoned there was no evidence of engine oil in the clutch housing. Anyway, says he's given it a good spray with Brakeclean and took it for a test drive and believes it should be ok now. He thought That even a tiny ammount of brake fluid in the clutch housing would be enough to make it slip. Does that all sound right?

300TDI by the way

Sorry, I can't answer your specific question about how much fluid affects the clutch

but....

I leave the drain plug out of the bell housing and timing cover unless going offroad. This way I can see drips on the ground under where I regularly park the vehicle and see issues when they are still small.

Not a bad idea by the sound of it!

Originally Posted by fender22

Per my first post, it was doing it to a lesser extent before the slave cylinder went. mechanic came and had another look this morning and removed the plug and said there was in fact a good desert spoon or two of brake oil in there. he also indicated that the save cylinder would have been leaking to some extent in the months up to when it completely went hence issue before. He reckoned there was no evidence of engine oil in the clutch housing. Anyway, says he's given it a good spray with Brakeclean and took it for a test drive and believes it should be ok now. He thought That even a tiny ammount of brake fluid in the clutch housing would be enough to make it slip. Does that all sound right?

I suspect that I have a similar problem with my 2a. Slipping in 3rd and 4th gear. I noticed that the drain hole was blocked with an oil/crud mix and when I cleared it maybe 2 tablespoons of oil ran out.
How did your mechanic spray the brakeclean on the clutch, up the drain hole?