Question for hydraulic clutch guru's...

[LanceMaster]

'85 CJ7 AMC 258 i6 / 4.2l w/NV3550
I converted to hydraulic clutch years ago when I still had a T-5 in it.

I switched to a NV3550 but there is not enough room by the brake vacuum boost can for the newer factory style master cylinder so I'm using the older style master cylinder and newer slave cylinder.

It feels like there is way too much pressure on the throw-out bearing. Clutch doesn't slip but I can feel firm pressure on the throw-out when clutch is released and I'm worried it may burn up on a long road trip. About once a month I have to release the pressure in the line or it builds to where clutch starts to slip.

I pretty sure the master cylinder has a larger bore than the slave cylinder.

Any thoughts?

 

[Patrick]

There should be zero hydraulic pressure when clutch pedal is at rest. If you have residual pressure, you might have incompatibility in your clutch components or incorrect adjustments.

 

[RiverandSand]

This^…
Also if both the slave and master are jeep components they won't have any residual checks. Do you have a spring on clutch fork to keep the throwout bearing in the retracted position? The air gap between pressure plate and throwout bearing should be around 1/4 to 1/2". While at the pedal is usually is 1" or better dependind on slop. Mine is around 3/8" because the chevy bellhousing and fork have slightly different ratio than the stock jeep but I am using the jeep cylinders.

 

[LanceMaster]

This^…
Also if both the slave and master are jeep components they won't have any residual checks. Do you have a spring on clutch fork to keep the throwout bearing in the retracted position? The air gap between pressure plate and throwout bearing should be around 1/4 to 1/2". While at the pedal is usually is 1" or better dependind on slop. Mine is around 3/8" because the chevy bellhousing and fork have slightly different ratio than the stock jeep but I am using the jeep cylinders.

I don't recall it having a return spring on the fork, and the diagrams I looked at don't show any. The slave cylinder has an internal spring but it pushes out. I seem to recall reading somewhere this later model system is designed to have light pressure on the throw-out bearing, but not sure if that's accurate. Remember this setup is for a TJ (in a CJ) and the clutch release arm is completely internal.

I'm curious if the mis-matched bore's with the larger master cylinder is prevent proper return? Any guys here with TJ clutch experience?

 

[RiverandSand]

Remember this setup is for a TJ (in a CJ) and the clutch release arm is completely internal.

I'm curious if the mis-matched bore's with the larger master cylinder is prevent proper return? Any guys here with TJ clutch experience?

Ahh... that changes things abit. The bore sizes do matter, Novak conversations site explain the relationship pretty well, also they sell an adjustable slave for the nv internal setup.