01E Clutch release bearing pre-load

I have a 302 engine/Audi 01E transaxle set up with a Kennedy flywheel/adaptor plate and Helix made clutch plate.
I'm keen to set the clutch release bearing pre-load accurately and am struggling for info.
I think the static set up should be 'X' mm/inches from the just touching position. My question is what is the 'X' dimension? Presumably just enough to load up the release arm/slave cylinder push rod in position and allow for future wear but not too much so it takes up the throw to release the clutch.
The transaxle and engine are out of the car and split so it's easy to measure and set up with a push rod of the correct length once I know the 'X' dimension. It's a standard Audi slave cylinder.
Kennedy say 1/16 to 1/8" CLEARANCE which I guess is wrong because the bearing is designed for permanent engagement. Unless they mean 1/16 to 1/8 engagement.
Cheers
Roger Allen

 

Having given this some thought. ASSUMING the pressure face on the Kennedy flywheel is in the same plane relative to the block face as the standard Audi flywheel then the new rod just has to be longer than the standard rod by the thickness of the adaptor plate (0.625") to maintain the factory Audi preload/throw - yes???? Not knowing the pressure plate position of the std flywheel it's only a check to see if I'm in the ball park. Currently I have a slave cylinder throw of 14mm and a pre-load of 10.5mm (6.5 to release the clutch + 4mm wear allowance) this is with a 97.5mm slave cylinder operating rod. The check above indicated 99.9mm - a difference of 2.4 which represents about 1.2mm at the bearing.
I think I'm in the ballpark and would be interested to know how others have faired with this issue.
My car is an RCR40.
Cheers
Roger

 

[Jim Cowden]

It is permanent engagement Rodger.
If the slave piston is not far enough back in the cyl it will bottom out when applied.
It should have a curclip in the end and as the piston travels out it will stop on it and your pedal will go rock solid.

Really at the end of the day you only have sleeve the bearing lives on as far as throw is concerned.
If you fit the slave , fork and bearing then push it back in as far as you can then release a little pressure then you will have your 2 extremes.

My pressure plate was further towards the engine than on the audi.
You cant put a longer pushrod in because the bearing may run off the sleeve.
I retained the same push rod but extended the bearing
I used the Audi bearing and machined a ring out of 4140 tool steel that simulated a radiused face bearing that my pressure plate required, I glued it on with loctite 406 prism.
It has never been an issue.

All cars have zero clearance slaves these days ,its just the way it is, they dont wear out any faster.

Hope it gives you help.

Jim

 

[Dave P]

I am not sure why you are thinking you need to preload the clutch. If you preload you will be taking away some of the clamping force of the clutch. If it is a diaphragm clutch the max clamping force is achived when the spring is at rest with throw out bearing released ,when bolted to flywheel and friction disc is installed.

 

[Dave]

Sorry for the thread drift but where would one buy a clutch fork and slave cylinder for an 01E from?

 

[Jim Cowden]

I am not sure why you are thinking you need to preload the clutch. If you preload you will be taking away some of the clamping force of the clutch. If it is a diaphragm clutch the max clamping force is achived when the spring is at rest with throw out bearing released ,when bolted to flywheel and friction disc is installed.

I would be thinking the preload talked about in the manual may purely be the spring in the slave, its not an adjustment.
German manuals often confuse.

Found a pic of the race if it helps

Jim

 

[Dave P]

Thanks for the clarification Jim.

 

Hi Dave,

Here are the Audi part numbers for the slave cylinder etc:
Slave Cylinder: 4AO721261
Spigot bearing: 034105313A
Bellhousing dowels: O1E 301153E

Hope that helps
Cheers
Roger

 

Dave,

I should add that the slave cylinder here is an all metal item secured by a single bolt through a lug on the slave cylinder. This lug then sits in a cast recess on the transmission.

R

 

Dave,

I should add that the slave cylinder here is an all metal item secured by a single bolt through a lug on the slave cylinder. This lug then sits in a cast recess on the transmission.

R

 

Hi Jim,
Many thanks for the detail and pic of your mod to the O1E release bearing. It's certainly given me another direction to consider. I must admit that I'd not thought about the amount of support that inner sleeve gives the bearing and by extending the rod the bearing might be going too far off the end of the sleeve. All previous advice I've been given is to simply extend the rod!
On my set up, I'm moving the bearing a further 8mm towards the nose and I'm not sure whether that is too much i.e. is the sleeve still supporting it sufficiently?
How thick is the spacer that you machined and glued to the bearing face?
Any thoughts on whether I can get away with the 8mm?
Cheers
Roger

 

As an alternative solution with a longer slave cylinder operating rod I'm now thinking of putting spacer washers behind the central support sleeve mounting on the three M7 bolts. This will push it forward by about 6mm to give additional support to the release bearing on full travel. Has anyone done this and was it successful?

 

[Dave]

I couldnt see why that wouldnt work or just get a new longer sleeve machined?
I am making all those type of parts for a 944 trans conversion at the moment. Easy cnc work. I sent you a pm asking for more info on your clutch plate?

Cheers
Dave

 

[Jim Cowden]

I recon extending the sleeve is more work personally but thats just me.
Besides that you make the sleeve to long it may make contact with the pressure plate.

That part on my bearing is about 15 mm ish.
It is the first part you see in the pic, the thin section directly below is the original bearing.
Look down the center of the spacer you can see the bearing face that it is sitting on.
If you mount the clutch to the flywheel ,put it in the press and release the pressure on the diaphragm till the clutch releases you can then measure the distance required for the bearing to travel on the sleeve.
Fit the bearing and fork to the box, move it in from the end of the sleeve the required distance for pressure plate release.
Measure from the socket that the slave fits into in the fork back to the face on the box where the slave mounts, right that figure down.
Fit the clutch to the engine ,fit the box, move the fork to the measure you have noted.
when at that measure push the fork forward to make contact on the pressure plate, subtract this figure from your 1st figure and that is the spacer you need to add to the Audi bearing.

The spacer I machined has a small lip on the outside to center out on the audi bearing ,this is so it does not walk of the audi bearing, like I said it is glued on,Loctite 406 is good shit.

Jim

 

[flatchat(Chris)]

What about a hydraulic release bearing ? (recognize the gbox Jim?)

http://www.malwoodauto.com.au/index.php?page=hydraulic_slave_cylinders

 

[andys]

Roger/Chris,

My setup is a QuarterMaster button flywheel and clutch assembly. I utilized the standard 01E slave and allowed the release bearing to ride against the clutch fingers with the spring load built into the slave. I'm using the radius faced release bearing with an adapter to fit it to the retainer on the clutch fork. It's actually pretty straight forward. When planning out this setup, I spoke at length with QuarterMaster's technical people and they opined that I should be ok with it setup in this manner; though some wear may occur at the release bearing face. I was concerned with the bearing constantly spinning, however the Audi spins constantly as well.

Andy

 

[Dave]

Would love to know more detail on your adapter / conversion Andy? looks like you have machined out the bell housing for clearance?

 

[andys]

Dave,

Standard 01E; bellhousing is machined that way from the factory. PM me if you have specific questions.

Andy