Leaking CV boots

[stownsen914]

I have 930 CV joints on my early 911 racecar, and I the CV boots leak at the large end. I am using the stock type boots with the stock clamps, pinched tight using special pliers. Previously I got the CVs to stop leaking at the mounting face with the flanges by ditching the 4 bolt / 2 drive pin setup for 6 bolts. Much better now, but the boots leak pretty significantly. Boots and clamps are relatively new.

It is worth noting that this happens only on the inner CVs. The outers don't seem to leak, I assume because they don't see the heat that the inner ones do.

Any suggestions how to stop this?

[Porboynz]

I make sure the mating surface where the rubber boot seats is completely free of CV grease (dry) before clamping up tight. Some folk then insert a section of thin tube at the small end of the CV boot to allow it to vent as it gets hot. (eg the tube you get with a spraycan of part/brake cleaner) Generally though this is not such a problem with inner CV's which have a limited arc of movement.

[winders]

What CV grease are you using?

[stownsen914]

Thanks guys.

I'm pretty sure I wiped clean the inner face of the boot before assembly.

For grease, I'm experimenting with Redline and Belray in this car. The leaking is the same with both.