1987 BMW 325 Clutch/Cylinder Problem

[DXH]

1987 BMW 325 Clutch/Cylinder Problem

Symptoms:
1) Slowly lost fluid from hydraulic resevoir over a period of ~ 1 month
2) At the end of this period the clutch pedal went to the floor with clutch still engaged.
3) Garage diagnosed a bad slave cylinder which was replaced. Clutch operated but was stiff and very sluggish.
4) Master cylinder was replaced, with no apparent effect - still stiff and sluggish.

Garage now wants to do surgery on the clutch assembly. I want to get educated before I authorize any more $$.

Thanks

[Keith M]

I think it needs to be bled again - sounds like there is still air in the system. Is your car still leaking brake fluid? If so, it could be the flexible line that attaches to the slave cylinder. Another thing - I hope you meant the clutch master and not the brake master.
Price for both the slave and hose is about $ 70. Maybe an hour to change including bleeding.

Keith

[DXH]

Reply to Keith: Thanks for the input. Installation has been checked, and there didn't seem to be any problem with air in the system. No hydraulic leaks evident. Yes, the *clutch* master cylinder was replaced.

More info - and the reason for my concern - the clutch operated normally throughout the period of the leak. No restricted range of motion & no other problems with operation. I parked the car one night, the next morning I pushed the clutch pedal in & it went to the floor and stayed.

When I describe the clutch operation as "sluggish" I mean that the pedal cannot be pushed in rapidly, and takes a substantial period of time (3/4 - 1 sec) to return to the top position.

Is it possible that there is a problem with the replacement slave cylinder?

[Jeron]

I dont know about the E30 but on the E36's there are several slave part numbers, one for each different clutch and they all look the same but have different valving. Maybe they put in the wrong part number.

For instance, I'm running a 328 clutch slave in my M3 because my aftermarket clutch is lighter and the M3 slave is too strong. I had no clutch resistance with the M3 slave.

[DXH]

Jeron,

Interesting thought. I looked around the web at the various slaves for the E30. Each slave seems to apply to a fairly wide range of models & years. According to invoice, the slave that was put into my 325 had a part number BEC-072-0946. I found a part 072-0946 that was applicable to my car., although I wasn't able to id the manufacturer.

Thanks
Doug

[Schneller]

There is only one slave cyl. applicable to the e30 & it is widely used in other BMW models of that vintage.

What pushes your clutch pedal back up off the floor is the spring tension of the clutch pressure plate acting upon the clutch slave cylinder piston. (essentially the reverse action of you pushing in the clutch pedal) If there is air in the clutch hydraulic system, then the return of the pressure plate to it's resting position will compress that air & not return the pedal to its "high" position. Furthermore clutch pedal effort will be light (as you're compressing air as well) and engagement will be close to the floor.

If the pedal is at the high position but feels firmer than normal upon applying pedal pressure, then the hydraulics are probably OK, but there could be a problem with the pressure plate itself, especially if clutch engagement isn't smooth. This requires pulling the gearbox at which point you should plan on installing a new clutch kit.

Good Luck

Mike Morris
Schneller BMW Performance

[BMWCowboy]

May want to pull ur lower panel down & check the pedal itself, have seen some that the actual pedal cracks and makes it alot harder to push