Reply to "McLEOD HYDRAULIC CLUTCH CONVERSION"

Free spacing between the back of the actuating piston and the aluminum housing is critical. The entire working of an annular hydraulic throwout is sealed by means of a 'quad-seal' in the bore. This special square seal/o-ring contacts the piston on its inside AND the housing bore on its outside. Quad-seals are designed only for linear motion, and the bellhousing, ZF case and flywheel/clutch will all expand with heat. So setting the required free play cold is vital. Note this is NOT clearance between the clutch and throwout bearing-its between the backside of the piston and its seal housing bore. If this space disappears in operation, the constant-contact throwout bearing (spinning with the clutch) will bottom and begin also spinning the piston inside the housing. Within 50 miles, the quad-seal will fail and begin leaking from this unnatural motion!

Well before vendors introduced adapted hydraulic throwout assemblies, I adapted one from Tilton Engineering intended for dirt-track racing to our ZF. The advantages of the annular throwout system are simplicity, a loss of 16 lbs of extra weight and direct motion with no losses- as long as everything is set up properly to begin with. The single disadvantage I've found is, if ANYTHING goes wrong, the ZF must come out to repair it! Mine has been in operation since 1993.

My Tilton provides a lug on one side of the main seal housing, that is anchored to the ZF with a small safety-wired allen bolt. Fore and aft adjustment of the components are provided by threading the whole Tilton seal housing and the custom threaded ZF nose adapter up or down so no spacers needed in this design. Good luck with your custom spacer- as I said, its dimensions will be absolutely critical.