Hydraulic Release Bearing Problem

Tim Terry

Supporter
Update: Removed the transaxle and release bearing. The seals looked ok, but I rebuilt the bearing with a QM seal kit - 5 mins work.

Reinstalled bearing and transaxle. Bled bearing - no issues or leaks. Adjusted clutch pedal stop longer by several revs, then tested for clutch engagement (while adjusting shifter linkage). No issues and I believe we will have prevented that from happening again.

Tim
 

Mike

Lifetime Supporter
I don't have one of the finished piece but here is one as I was mocking up with cardboard.

 

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Tim Terry

Supporter
Mike,
I wish I could have envisioned that. If/when I have the transaxle out again, I'll do something similar. Thanks for sharing!
 

Mike

Lifetime Supporter
Did you use the Quicktime bellhousing and McLeod clutch/PP? I noticed you used several of the spacers behind the T/O bearing. I got several from Dennis thinking I might need some adjustment. I ended up not needing any of them. Wondering how there would be so much difference.
 

Tim Terry

Supporter
Yes, I used the Quicktime housing and the McLeod clutch/PP. I followed the installation instructions carefully, measuring multiple times and using multiple people. We ended up using 5 spacers, I believe. A few trips around the block and a round-trip (25 miles) to get the car weighed. No leaks and no issues.
 

Tim Terry

Supporter
The entire setup came from Olthoff (Quaife transaxle, bellhousing, clutch/PP, upgraded shift linkage). I can locate the paperwork, if needed.
 

Steve

Supporter
Resurrecting this old post. Similar to Tim, I had to use quite a few spacers although my transaxle is an RBT. There was a bit of "rocking" back and forth which I didn't like to see, especially considering the precise nature of the settings. Has anyone had experience with the external slaves? Paul Whitlock has been using one sourced from a Pantera shop. Wondering if there's a con to using this. It would avoid ever having to take all this apart again. It's quite a chore when you have a dry sump with lots of bits attached to the rear subframe...
 

Steve Julius

GT40s Supporter
My CAV GT40 ZF was converted to external slave by the PO. He got tired of leaky internal ones. Conversion kit was provided by Pantera Performance in Castle Rock, Colorado. Price was a little over $1,000 back in 2013. I have owned the car for about a year and a half, and have had no problems with the conversion.
 

DaveM

Supporter
After two McLeod internal slaves failed I went to a CNC external slave one. You also have to get the RBT external arm kit part #1001 though. 8 years now with no problems.
 
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My understanding is the QM units are more reliable than the units from McLeod. Mine has not been a problem knock on wood.
I have the McLeod hydraulic throw out bearing on my 289/top loader combo. Several things...
1. The distance from the trans mounting flange to the clutch fingers must be carefully measured so the correct length main body can be utilized. Follow the instructions to the letter!
2. The bleed line and pressure line MUST be routed and held away from the rotating clutch and the bleed line must be very long to reach up into the engine above the clutch level. ( I have mine wore tied back away from clutch - I forgot to tie it back up after fluid change and the clutch ate thru the braided line and I lost pedal 6 blocks away from my shop)
3. The NBR Nitrile o-rings in the hydraulic throw out bearing can be replaced with a Viton FKM compound for better high temp performance. I replaced the seals in mine and increased the hardness to a 90 durometer. This will help in life and wear.
Contact me if you need any. I am in the engineered rubber and plastics industry and have access to these specialized materials in o-rings and quad rings.
 
Some more options re hydraulic slave bearings --- extra stroke, works great with either 5/8" or 3/4" master
 
"Unless otherwise specified" most generic automotive hydraulic systems re:- clutch and brakes use seals / orings compatible with only a DOT 4 type fluid ie silicon based or other ? maybe detrimental to seal material = failures
 
I used AFLAS elastomer o-rings. Good to 230C in brake fluids. I said earlier is used fluorocarbon FKM. THAT WAS WRONG...when I looked up the actual material I used.
 
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