So i have a quatermaster twindisc clutch and a hydraulic release bearing, i am having a slipping issue mostly in 4th and someitmes in 3, the odd think is that it doesnt happen all the time and when it does its only for a second or so, im assuming the clutch slips a little bit then grabs, the clutch engagement is way at the top of the pedal(no pedal stop installed yet) i have an inspection port on the bellhousing and the clutch discs are very thick, i feel that the clutch should be engaging so high up on the pedal, i tried adjusting the adjuster inside the car and it is basically all the way out and the clutch still seems to slip,(int.) i can only assume that the bearing was not shimmed correctly and isnt fully disengaging? but i am new to twin disc clutches and hydraulic release bearings, any help would be appreciated

 

how many miles? How much power? How many launches? alot comes into play with clutches and opperate why they do

 

https://www.evolutionm.net/forums/ev...age-usage.html


Read up, some good information in here about the old style Quartermaster Twin disks

 

sry for late reply, the clutch has been in there for less tan 8k miles, i can physically see the discs and they have alot of life in them(i know discs dont play the only factor in clutches) the car has 600whp i havent launched it yet

 

If you didn't read through the link I posted, do it. Your problem is the hub from the inner clutch (flywheel side) is contacting the outer clutch hub (basket side). With the way the quartermaster clutch is designed once the clutch has been worn down the hubs ride on each other resulting in slipping of the clutch.
When you go to change out your clutch, take the flywheel side clutch and get the hub machined down between .050" & .065" of an inch to get the rest of the meat off the clutch disks. By getting the hub machined the inner and outer hubs will no longer contact, which equals no more slipping.

 

I did read that and thank you for the info, im pretty sure thats the problem

 

awdwannabe
This occurance would only be if you have a standard hub clutch assembly. If it is the Gear Drive disk pack, it would not do this as the hub design is completely differrent and does not bottom out on the inner hub.

It could otherwise be two different problems -- both would be Hydraulic TOB related. First, if you installed too thick of a shim in the hydraulic TOB that the unit when fully relaxed (clutch engaged, TOB bottomed out) is putting load on the clutch cover diaphragm spring and partially disengaging the clutch. Putting in a thinner shim would be necessary. I would start with subtracting 0.035" of shim from the hydraulic TOB. Second, if no shim is installed in the hydraulic TOB, and you have already bled and adjusted the clutch pedal assembly at the master cylinder rod to reduce clutch pedal throw and it does not fix the problem; then you should see clutch hydralic fluid pressurized when cracking open the hydraulic TOB bleeder valve. If so, then there is a likelyhood that the transmission needs to come off, and the Hydraulic TOB requires machining of the backside of the hub that affixes to the bellhousing. The hydraulic TOB will require disassembly, and machining to the backside of the flange to remove around 0.100"-0.150" of material while retaining the lip for the TOB to bottom out on. Then, after the backside is machined, you will reassemble the TOB and fully lubricate the two sealing o-rings with a synthetic grease and reassemble, then fill fluid through the two stainless lines so there is no air, cap off the lines, then reinstall the hydraulic TOB onto the bellhousing, mount the transmission, and attach the hydraulic line back to the existing clutch line. Test the hydraulic TOB after being bled and confirmed that there is no air. There should be no pressure on the relaxed position on the clutch cover diaphragm. If there is more than a 0.020" gap in the relaxed position, use your supplied shim kit to find the right thickness shim or combination of shims to take up the slack. This can be done by measuring the body height of the TOB in the bottomed out position, then installing and pressurizing the TOB by pushing the clutch pedal a couple times; in the relaxed position, it will now have a taller body height and can be measured by taking the transmission off and measuring the new TOB body height. The difference in height will be your shim thickness needed under the TOB to have it work properly. You will disassemble the TOB again, install the shim under the TOB, then re-lube the seals, reinstall the TOB, and reinstall the TOB assembly and transmission back onto the car. You will also need to check and readjust your clutch pedal assembly. The clutch should fully disengage around 1-3" off of the floor.

Quarter Master knew of this problem on a couple of my customer's cars in 2011 and we did some adjustments in-house for the problem ones that I had. I contacted Jeff Weigert and Jeff Tickes at QM today to look in their records to see what exact amount we machined off the backside of the TOB flange as this fixed the problems I saw on my customer's cars.

All of my customers cars with these problems were 2005-2006 Evo 8/9 5-speeds with stock crank 2.0L's with the 8-leg clutch on the race flywheel (Part Number 509544 machined on the backside of the flywheel) only.





***EDIT*** The TOB bottoms out at 0.175" on the taper of the flange, so you should only machine a maximum of 0.150" off the backside and retain a bit of the tapered lip so the TOB can bottom out properly.

 

went from qm to comp clutch.. same problem