Re: Fwd: <E30> Replaced clutch master cylinder

[Michiel van Wessem <jmvw@xxxxxxxxx>]

Hi Larry!

Thanks for your message; it was a pleasure reading it. 

Some replies to your observations:

- - I knew it was the master cylinder and not the slave because I didn't see
any fluid leakages anywhere. If the slave leaks, eventually the fluid has
to come out. Only the master has the line going back up to the reservoir. 

- - I can see what you mean about the piston shooting out of the slave
cylinder hen you depress the clutch pedal with the slave out. It *is*
risky, and a warning is probably appropriate. Fortunately, I got a taste of
the force the slave piston has and I told the Mrs to go super slow, so I
could see what would happen. 

- - Yes, there may indeed be junk in my slave cylinder. I'll think about
replacing it.

- - My pedal isn't coming up all the way because I broke the center bolt in
that damn spring that is supposed to keep the pedal up to the top. If I had
a welder, I would have just welded the eye back on to the bolt. I'm still
waiting for the new spring. 

Best regard, I'm glad you like these things too! And enjoy your coffee :) 

Michiel

It's probably wise to point out the things that you pointed out. 
At 09:32 AM 4/8/00 -0700, you wrote:
>Michael:
>
>Ah, ye of little faith!  Of *course* people read this, but
>most are very selective; either model bigots ("M3 or Die!")
>or lazy . . . ;~)
>
>Cool story about the Ford; bummer.
>
>Lots of observations, since I am neither of the characters
>described above:
>
>- I don't think you are done.  Yes, the hydralics in these
>   guys are regular maintenance items; common to replace in
>   100K+ vehicles.  So your dealer certainly stocks them.
>- But, I guarantee she/he stocks more slave cylinders.  Hmm.
>- The symptoms you describe are often highly temperature
>   sensitive.  Cold = shrunken seals in the cylinders which
>   = leakage.  You might want to consider this variable.
>- The plugged bleed screw on the slave cylinder belies one
>   of your assertions; that you don't need to bleed this
>   system unless it has 'debris' in it.  Yours seems to!  ;~)
>- You can try to clear the valve; but you really ought to
>   replace the slave cylinder entire.
>- Your test technique of having a partner depress the pedal
>   with the slave unmounted is risky.  Many the DIYer has written
>   to the Digests in chagrin, that in so doing, they propelled the
>   contents of the slave cylinder across their garage.  :(
>- In addition, your reasoning is good as far as detecting
>   leakage goes, but it does not distinguish between the slave
>   and the master leaking.  Op cit. above.
>- Lastly, the cruise control cut-out switch is adjustable; if
>   the pedal is not coming up firmly (and I have had the same
>   experience with the assist spring) it leads me to further
>   suspect the slave cylinder.
>- And *really* lastly, can you tell my morning caffeine is
>   pretty on-line?!?
>
>Have fun; having fun:  Larry F.
>
>>Date: Thu, 06 Apr 2000 23:05:50 -0400
>>From: Michiel van Wessem <jmvw@domain.elided>
>>Subject: <E30> Replaced clutch master cylinder
>>
>>Hi.
>>
>>Tuesday, on my way home, the clutch started to engage while I had the pedal
>>down. Also, the clutch pedal wouldn't come up much anymore. At first, I
>>could lift the pedal up by putting my foot under the pedal and the clutch
>>would disengage long enough to shift quickly if I pressed it down quickly,
>>but I had to be quick because the clutch would engage all by itself while I
>>had the pedal down. Soon enough, it became so bad, I couldn't shift anymore.
>><snip>
>>I had my wife hold down the clutch pedal while I removed the slave cylinder
>>from the transmission. I wanted to see if I could push the piston in. I'm
>>kind of smug about this: if it would push in, no matter how slowly, the
>>master cylinder had to be faulty. Because I hadn't seen brake fluid, the
>>fluid had to be leaking back up towards the brake fluid reservoir.
>>
>>Indeed I could slowly push in the piston. The next day I bought a new
>>master cylinder (fortunately, a dealer had this in stock; the dealer was
>>expensive, but renting a car was more expensive).
>>
>>I installed the new cylinder the same evening and that fixed it!!
>><snip>
>>- - I broke the pedal's "compression spring", but even without that thing the
>>clutch works fine. It's just that sometimes the cruise control switches off
>>because the pedal isn't pushing against the clutch switch hard enough. I'll
>>replace it when I get a new one in a few days.
>>
>>- - This problem was not in the clutch troubleshooting table at
>>http://www.bmwe30.net/, but the fact that the dealer had that master
>>cylinder in stock might indicate that it's a common problem.
>>
>>- - I wanted to bleed the clutch, but the bleeder opening on the clutch slave
>>cylinder didn't let anything through. Still, the clutch works fine. My
>>conclusion is that it doesn't matter at all if there's some air in the
>>clutch hydraulic system - the forces aren't anywhere near that of brakes.
>>The only reason I see for bleeding the clutch every now and then is to get
>>any possible debris out of the lines.
>>
>>Anybody really read this? Well, thank you!
>>
>>Michiel (325es <http://www.monmouth.com/~jmvw/cars/BMW> )
>>- ----------------
>>From Jackson, NJ
>>
>>   e-mail at night: jmvw@domain.elided
>>  e-mail while day: jmvw@domain.elided
>
>-- 
>Larry Franks
>Issaquah, Washington
>'95 540i/6
>'95 M3
>

- ----------------
>From Jackson, NJ

  e-mail at night: jmvw@domain.elided
 e-mail while day: jmvw@domain.elided

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