Mechanics

BLEEDING A HYDRALIC CLUTCH

Audi A4

Is there a special trick to bleeding the hydralic clutch. We installed a relacement 5 speed and used the original slave and master cyl. And cannot seem to get any good fluid flow from the bleedr. I have even applied about 10 p.S.I. To the resivoir to force fluid but still unable to obtain any pedal.
1998 audi a4 v6
AD
Avatar
RE
September 8, 2007.




Hi there,

As long as the master & slave cyl are in good order there should be no reason why you don't have a good pedal. Now bleeding a clutch is a bit different to bleeding brakes. To bleed a clutch top up the fluid, depress clutch, open bleeder, with pedal still on floor, and with fluid / air expelled close bleeder, raise pedal and re peat 5-6 times, or untill no air is evident. If you can not get a good pedal after this you have air entering the system some where so you will have to inspect the relevant cylinders for a problem.

Mark (mhpautos)

Mhpautos
Sep 9, 2007.

Tiny
RE
Sep 9, 2007.
[/quote: 26b7ac6815]

Tiny
RE
Sep 9, 2007.
Hello Mark,
After removing the slave and master cyl. I discovered I was not getting fluid from the resivoir to to master cyl. What I found was the nipple on the reservoir where the hose connects was still closed off from the factory which did not allow fluid to flow to the master cyl. I appreciate the time you spent and much thanks appreciated. All is well and have a happy customer. That was a first for me especially since the car has 140,000 miles and has had the clutch changed once before.
Thanks again, Bob

Tiny
RE
Sep 9, 2007.
On Audi A3 1.8 the master cylinder was renewed. Bleeding was tried by pedal pressure - then venting which did not work. Back bleeding by injecting fluid into the vent screw - this gave half to full pedal which varied for no apparent reason. Pressurising the master cylinder and venting did not improve this. The master cylinder has a tapered slot running the full length of the pressure side above the piston. It is almost impossible to remove air from this void. The cylinder was dismantled, a 1.5mm hole was drilled into this void through the wall of the cylinder and c/sk screw fitted. The screw was accessible with cylinder assembled to the car and was very near the back flange. This was used as an additional vent - Superb clutch, never been so good.
AD

Tiny
Doubledart
Sep 25, 2007.
The bleeding was accomplished. What was found the end of the nipple on the resivoir where the hose that feeds the master cyl. Was not opened up from the factory. So there was no fluid getting to the master cyl. We cut the end of the nipple open, reattached the hose and finished the job.

Thanks again, Bob

Tiny
RE
Sep 25, 2007.

AD