[V8] clutch

Sun Nov 27 22:06:57 PST 2011

... apologies for the delay ... I have been so busy ...

... when I find some other failure just after performing some other
operation, the first thing I suspect is the new problem is somehow related
to the last thing that I did.  In this case you started having clutch issues
just after working on the steering rack ... my recommendation would be to
look around the areas you worked on ... fasteners that were tweaked, that
sort of thing.  Could you have tweaked the metal line that comes through the
firewall for the clutch?  Pinched or damaged the flexible line?  How about
the feed line from the brake M/C reservoir that goes to the clutch M/C?  Is
it pinched?  That is definitely in the neighborhood of the rack ... 

Good luck!
Steve Buchholz

-----Original Message-----
From: v8-bounces at audifans.com [mailto:v8-bounces at audifans.com] On Behalf Of
Dave Saad
Sent: Thursday, November 24, 2011 8:13 AM
To: audi fan
Subject: Re: [V8] clutch

Hi Scott,

here is what I have done so far:

I have the original slave from the first clutch job - I just replaced it
because I was in there. It is aluminum, the "new" one is iron. Both do the
same thing, neither shows any sign of seal leakage, both look physically the
same (aside from iron v aluminum)

The "best" bleed procedure seems to be:
	-> remove the slave (still attached to hose) from tranny
	-> hold vertical (bleeder nipple up) and do all the usual bleed
steps.  I have a pressure bleeder, and do it manually as well.
	-> test (1) by compressing the slave piston against the frame rail
(just hold it down with my palm), then having my trusty assistant (12 year
old daughter) press the clutch pedal to the floor.  The piston extends about
1.25 inches, which is not the full travel of the slave, but does look to be
about the full travel of the master.  The bores look to be about the same
diameter so I would expect the distance traveled to be the same.
	-> test (2) let the slave spring fully extend the piston and bleeder
valve closed. Everything should be full of fluid and the piston is bottomed
out so if I (carefully) press the clutch I should immediately feel solid
resistance with no springiness - and that is the case.

I am not sure what you mean with your test and the "burp".  If there is no
air in the system, and I did that procedure, at the end, the clutch pedal
should be up, the slave cylinder should be fully returned and expel any oil
back into the master/reservoir so what would burp?  Is there any sort of
check valve in there?

Another observation - when I install the slave, it looks like the piston rod
hits the throwout arm such that I have to compress the piston about 1 inch -
maybe even a little less.  That says I am not getting the full 1.25 inch
throw.  Do you know if that sounds normal? or know what the typical throw of
the throwout arm should be?  Is there something that could silently and
quickly fail to cause this?

Again, if I start the car in gear, it is as if I am at the point where the
clutch is just starting to release.  I can sit there and idle but cannot
shift in or out of gear.  It makes no unusual noises and is smooth.

And on Rule #1 - are you thinking the new master could be bad? is there a
difference in the V8 vs say a 200 in this part?  The new one behaves the
same as the old one, and for that matter, I feel the same flexing of the new
hose as I did on the old one.  That surprised me a little.

thanks
Dave

On Nov 24, 2011, at 8:19 AM, Scott Justusson wrote:

> Rule #1:  New does not mean known-good Rule #2:  Known-good is better 
> than new.  See Rule 1 Rule #3:  If a symptom points to a new part - 
> see Rule 2
> 
> Dave:
> Without any other reading than the pedal, this says slave cylinder or air
in the lines.  For slave, I bench bleed all slave cylinders prior to
install. I also use a Snap-on pressure bleeder to bleed.
> 
> Test:  Take your hand and manually pump the clutch pedal 50 times, to the
floor and bring it back up manually.  Crack the bleeder screw at the slave.
Does it burp with the release of the built up line pressure?  If not, likely
bad slave.  OR, you haven't gotten all the air out, or there is a leak.
> 
> It's possible you have bent/faulty tines in the clutch PP.  Can you get
the clutch to actually release?  Normally, I see Clutch to the floor with
nothing as Master, clutch almost to the floor with something as slave, and
no clutch release at all as faulty tines.  The only other thing I've seen
only once, was a similar problem on a  'miss' of the TOB fork detent
installing the slave.  
> 
> HTH
> 
> Scott J
> 92 v8 ABT Chipped
> 
> 
> -----Original Message-----
> From: Dave Saad <dsaad at icehouse.net>
> To: audi fan <v8 at audifans.com>
> Sent: Wed, Nov 23, 2011 9:58 pm
> Subject: [V8] clutch
> 
> well - this sucks.
> My clutch stopped releasing fully just a few days after I got the new 
> rack installed.  I hoped it was some sort of hydraulic problem - and 
> it looked good for a while that it was.  The master had a broken 
> internal spring, and the hose was looking like it might be stretching 
> a little so I replaced both.  The slave is good.  Still no go.  I 
> can't imagine what might have gone wrong with the clutch to cause 
> this.  It made no sound.  It just won't release all the way.  It was 
> replaced about 70K miles ago.  The symptom is the pedal feels a little 
> soft, and is most of the way down before it starts to really feel like it
is doing any work.
> 
> I have tried bleeding the system every way I can think of and am 
> (99.46%) certain it is not that.  This is a real PITA to do by the 
> way.  I think the easiest way to bleed the clutch is to hang the car 
> by the back bumper with a crane so the air bubbles go to the top of 
> the slave.  What I really ended up doing was bleeding the system with 
> the slave off the transmission and turned vertical.  This of course 
> made installing the slave lots of fun since you have to compress it 
> with your pinky while installing the bolt with your tongue - all while
blindfolded.  I hope DOT4 is not poisonous.
> 
> So - it looks like I will be pulling a motor real soon.  In the 
> meantime of course I am driving my beat up old '83 ranger with who 
> knows how many hundreds of thousands of miles on it.  It still has all 
> original hydraulic parts for both clutch and brakes.  It would still 
> have the original clutch too except I changed it a few years ago 
> because I was towing my trailer and just could not believe it was still
good.  It was.
> 
> Grrrr
> 
> Dave
> 
> 
> 
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