Clutch & master cylinder woes

[greybeard]

I've got an '87 325i with 155,000 miles on it; I've only had it for 6 months. The clutch pedal suddenly began sticking to the firewall so that I had to pull it off with my foot. My mechanic checked it out and found that the master cylinder and the clutch master both were leaking, so he replaced them both. Two days later my brakes nearly failed (I had to really lay on it to stop). Mechanic checked it out and could find nothing wrong, but he bled the system and got some air out. Two days later my clutch pedal failed again, and back to the mechanic. Bled again. Next day it failed again.

They finally decided the new master cylinder from the factory was defective so they replaced it with a new "upgraded" master cylinder. Everything was fine for four weeks, but the clutch pedal has failed again. The mechanics are at a complete loss; said they will replace the "distribution valve" (?) but they really just don't know what's wrong.

Any ideas?

 

[e30fr3@k]

Honestly, I don't have a solution, but I did have a very similar problem that you may be intersted in hearing. I was pulling into my driveway one day, about a day after I replaced my pads (didn't bleed system or drain any, completely closed) and my car kept going after I pushed the clutch in. Mechanic thought it was the pressure plate, but after looking at it he decided it was the clutch master cylindar. The only thing I can think of is that the brake fluid system had too much pressure or something, and just burst at the path of least resistance. The leaking would explain that, but frankly, I'm just a n00bie. In anycase, it's a thought and I hope it helps.

 

[xLibelle]

your original problem was a do it yourselfer. $20 kit (if even that much) to replace the seals in the master.

how do you mean failed? it wont rebound?

 

[Chesty Bonds]

Has it affected your brake system at all? Because the clutch and braking systems feed off the same fluid.

Also, does your clutch grate when you select reverse or first?

 

[greybeard]

Yes, the brakes have gone out as well as the clutch, though not at the same time.

No grating or any noises whatsoever, just a clutch pedal that sticks to the firewall.

 

[Ben]

get a new mechanic. i replaced the slave on my car at 188k when it went, and then the master at 195k. im almost at 205k and everything works perfectly.

 

[e30fr3@k]

get a new mechanic. i replaced the slave on my car at 188k when it went, and then the master at 195k. im almost at 205k and everything works perfectly.

Now, I mean no disrespect in saying so, but I don't feel that you could pin this on the mechanic. I've heard tons of stories about problems that keep reoccuring despite the good efforts and decisions on behalf of the mechanics.

On a different note, in response to bonds's questions about grating, what does grating imply? Because my dad's old accord ALwAYS did that and I just thought thats the way things went for those types of cars. No BMW I've ever driven does that, but quite a few asian cars.

 

[mjbst111]

On a different note, in response to bonds's questions about grating, what does grating imply? Because my dad's old accord ALwAYS did that and I just thought thats the way things went for those types of cars. No BMW I've ever driven does that, but quite a few asian cars.

Thread burgler! haha

grinding in first and reverse could be a few things but mostly it happens if the car is moving while you try to put it in one of those gears. All cars have syncros in first so grinding only happens when it wears out.

BMW's have syncros on reverse as well, so no grinding on a BMW as long as they aren't worn out.

If you don't want to grind (in a japanese car or some other car...) stop the car before an attemp to shift.

You would have to let the clutch out in neutral while stopped before trying to shift as well if you want a flawless shift.


Back to the original topic... when this happens does any fluid leak?

Or perhaps your slave cylinder is shot.

 

[Chesty Bonds]

On a different note, in response to bonds's questions about grating, what does grating imply?

It means that your clutch is gone.

 

[e30fr3@k]

It means that your clutch is gone.

Clutch or syncros...if it were the clutch, why only first and reverse?

 

[Chesty Bonds]

Clutch or syncros...if it were the clutch, why only first and reverse?

That's just the way the E30 behaves. I've asked my mechanic about it and he reckons that if first and second crunch when selected then this is the best indication that the clutch is worn.

 

[mjbst111]

chesty... if your mechanic told you that, i highly recommend that you not return to him.

 

[Chesty Bonds]

chesty... if your mechanic told you that, i highly recommend that you not return to him.

Why? If you think about it, it actually makes sense. BTW, my mechanic is German and he is a fully trained BMW technician so i think he knows what he's on about...

 

[Ben]

the best thing to do to check the clutch is to look at it and see how worn it is, or if possible to check it with a micrometer. if its really bad, it will slip when you accelerate hard. it has absolutly nothing to do with first and second. if the clutch is worn, it will take less to disengage it, so its pretty much the opposite of what your mechanic said. now on the other hand, if theres a very small air bubble in the system, pushing the pedal may not fully disengage the clutch, and that would cause grinding in all gears.

 

[Chesty Bonds]

the best thing to do to check the clutch is to look at it and see how worn it is, or if possible to check it with a micrometer. if its really bad, it will slip when you accelerate hard. it has absolutly nothing to do with first and second. if the clutch is worn, it will take less to disengage it, so its pretty much the opposite of what your mechanic said. now on the other hand, if theres a very small air bubble in the system, pushing the pedal may not fully disengage the clutch, and that would cause grinding in all gears.

Actually i thought about what you said and you're absolutely right. I can't believe i wrote that s*** now that i realise what i'm saying. I must've been referring to the clutch pressure plate - if this is pushing (and pulling) the clutch crookedly then, yeah, this will cause grating because the clutch wouldn't be completely disengaged.

Woops