Hydrualic throwout bearing and clutch adjustment

Fuelie74

Fuelie74

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Joined
May 7, 2008
Messages
770
Location
Monroe, WI
How tight are you supposed to adjust a hydraulic throwout bearing?

I am using a Howe hydraulic throwout bearing in my 74. When I put this together I followed the directions provided by Howe. I am really starting to think that might be my problem. Most other things I have read about adjusting a throwout bearing talks about clearance or air gap. Howe directions say to have none or a slight preload.

Here is a link to their directions.
http://static.summitracing.com/global/images/instructions/hre-82876a.pdf
 
I called Howe and talked to their tech person today. His responce was that the original bearing design needed to be set up that way because of lack of travel.

He then told me that he disagreaded with thier direction and that I should give it 1/16 to an 1/8 inch airgap.

This seems like a better option to me. So I am going to drop the transmission and reshim the bearing.
 
I've never used a hydraulic throwout but it seem I have heard that the bearing needs to be in light contact with the fingers so that the clutch fingers force the piston all the way back. Sounds like, if you were to leave a gap, the fingers would only force it back to the gap (reducing total travel)?
 
I believe your right. The pressure plate would only push it back to the gap and you would lose some travel.

The problem is when the clutch wears the fingers on the pressure plate move back. So if your shimmed with no play or posibly preload on the bearing it will only get tighter as the clutch wears causing the clutch to slip. Plus without that gap you have no way to check the adjustment of the clutch.

I wonder how much travel is acually required to release the clutch?
 
Hmmm, that is a very good read. I am running a 10.4 clutch so by this information I would need .78 travel.

The original HTOB that Howe sold for the T5 had .549 travel. Mine is the new design and it has .688 travel. That would give .100 pressure plate movment with a 1/16 air gap.

Tight but I will give it a try and see what happens.
 
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