Clutching concerns ...

[steveb@falcon.kla.com (Steven Buchholz)]

... must be some kind of clutch virus going around ...

Nick Varvarigos writes:

> I need to bleed my clutch and have the following questions:
> 
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> 
and then Bill Murin writes:

> My q with its new clutch developed an interresting malady yesterday.  #2 

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WRT Clutch bleeding:

1 - I have successfully bled the clutch circuit the same way that I do the
    brakes.  I can't see that doing such could ever damage the seals on 
    the master cylinder, because you don't get any additional travel in the
    pedal.  I can't see that there would be the possibility of damaging the 
    slave for similar reasons (given that the slave is connected to the 
    clutch mechanism that is) ... when you depress the clutch pedal it can't
    hyperextend, and when you release pressure by opening the nipple the 
    piston can only return to the rest point.  I found that after the 
    rebuild that the first stages of clutch bleeding can be done single-
    handedly.  Without the return force from the clutch itself, the pedal 
    springs go over-center and provide force to hold the clutch to the 
    floor [which explains why the pedal sticks to the floor when the hyd-
    raulic mechanism goes south].  

2 - Pressure bleeding - I've always wanted to rig up a pressure bleed 
    system for myself.  Basically all that you need to do is provide some
    means of feeding slightly pressurized brake fluid into the system.  
    This usually involves hacking up an old brake fluid reservoir cap to
    allow you to seal the system.  I have a tank from an old party balloon
    kit (~$10 at COSTCO ... and you get to talk like Donald Duck too! :)
    which I plan to use as the pressure vessel.  I'll probably attach an
    old metal Schrader valve stem from a wheel to allow me to attach my 
    regulated air compressor output, and then rig a pressure hose to 
    connect the bottom of the helium tank cum fluid reservoir to the 
    modified brake reservoir cap.  Once the apparatus is hooked up you 
    can bleed the system by yourself and the process is much quicker because
    you aren't always having to press, bleed, release, repeat and check the 
    fluid level in the reservoir all the time.  You simply open the bleed 
    nipple until you like what you see coming out, close it and move on ...

3 - I actually discussed this in #1

... and for Bill, in my case the master was in fact the source of precisely
the same symptoms you describe.  I would think that a failure of the slave 
could have similar manifestations.  Perhaps the fact that it does attempt to
return is more indicative of a slave failure.  I know for a fact that Beck-
Arnley makes a rebuild kit for the master.  Of course it is possible to 
procure replacements as well.  The caveat here is that there are at least 
two different flavors of quattro master cylinders, so if you decide to take 
that route, make sure that the person who is taking your order gets the 
right one!  The urQ/4kq clutch has a long actuating rod and has studs on the
mounting flange whereas the '88 5kq has a much shorter actuating rod and holes
for the bolts that attach the MC to the mechanism.  I procured type #1 for my 
#2 5k from Carlsen on a Friday.  I needed to have the car up, so I turned my
#1 MC into a #2.  Oh yeah, the plastic tip that the incoming hydraulic line 
hooks up to is different for each as well.  My mind is a bit fuzzy after the 
ordel, but my recollection was that I got an OEM equivalent from Carlsen for 
~$75.  You can get a rebuilt kit for a third that cost.  Since I'm getting a 
bit long winded on this one I guess I'll search my archives for the P/N ... 
[Beck/Arnley Worldparts part number 071-7379 for M/C]  This rebuild kit will 
work on either flavor of master cylinder ...

... and a note to all ... whenever you have someone else bleed your "brakes"
make sure that you explicitly specify that you'd like to have the clutch 
bled at the same time.  I assumed they would ... they didn't!

Hope this helps!
Steve Buchholz
s_buchho@kla.com
San Jose, CA (USA)