pp000830

I think the direction of this thread is pointing to the boot design or material as a solution to the harsh working environment as root cause is a fruitful direction.
I would find an alternate designed boot, possibly of an alternate material, made by an alternate supplier, maybe even one made for racing applications as the next retrofit and see if your issue subsides.
Contact these folks, they may have a solution or one of their customers does for your application: Trelleborg Boots.
Andy

IainM

If the problem was low quality boots or general high temperature operation, why isn't this endemic?
I think there's something floating around in your back wheel area that is slashing the boots. I heard a tale today of a tire that separated and had a circumferencial detatchment of the tread that flopped back when stationary but whipped havoc at speed.
Something is being pulled into contact at G-force but is hidden when stationary.
Think outside the box here.

IainM

The air pocket expands and blows out the boot. Interesting argument for more grease in boot. Hadn't thought of that.

Holger3.2

Contacted some dealer and Trelleborg, lets see what comes out.
I'm absolute sure that there is nothing pulled out under g-force and fine when stationary, especially not on both sites ...
In regards to the air pocket, if an issue, that would most possible be resolved by not putting the inner clip as recommended in the above mentioned initial thread. Any pressure could escape than, no straw needed anymore.

Holger3.2

Got today an answer from Trelleborg, but that might be a little overkill.
But at least they put some efforts into it!
Anybody interested on a group sale

Hello Holger
I have been through our list of existing CV Boots and cannot find anything from stock that would fit this joint. The only way we could help you would be to design a new CV Boot; this would however require a new manufacturing mould, at a cost of at least £1,200, there would also be a minimum order requirement of 10 special CV Boots. The boots would be designed to fit your applicational requirements and manufactured in one of our high strength materials. In very low quantities, the boots are likely to cost £45 each. So overall there would be an investment of at least £1,600 to correct this problem.
Please let me know if you would be interested in us looking into this issue further for you.
Just for your information, our sister company Tritec Sealing Solutions supplies parts for the Porsche 356 racing in the USA, data sheet attached: Not sure if any of these parts are transferable to the 911.

Regards

So the new boots without inner clip survived the first trackday, lets hope they will last longer

Holger3.2

Spookes:
you deleted further down your post "My 3rd torn CV boot; almost do it blind folded - maybe" ??

in your case, any similarities to this thread ... ?

Spokes

I accidentally posted in the 993 forum, the post is now in the 964 forum. Not the same issue as yours. It is my third cv boot in 10 years across 2 cars. No repeats, just age of boots.

Holger3.2

That sounds still reasonable

Holger3.2

s**t, overlooked this info from Badabing ...

can't measure the bolt circle anymore. Does anybody know if theses boots would fit?

LimeyBoy

I just measured my drive flanges which are off the trans at the moment = 95mm PCD.

samurai_k

@Holger3.2

Last night I repacked my rear axles. One of the things I noticed is there is vent hole in the axle itself. I experiemented and blasted some compressed air into it and noticed it would expand both the inner and outer joint boot. an idea maybe your joints can't vent and are ripping when getting hot?

Holger3.2

Hmmmm, interesting
never got that idea. Just in my mind is the center hole in the outer site of the shaft. I know that if it gets really hot, the very liquefied grease from the outer bearing gets out of that hole!
I will observe that for sure! Thanks



Thats how it looked when the grease came out in the old days .....

Holger3.2

That comes pretty close. Worth to pursue. Thanks

SpeedyC2

This is a great little tidbit I had never heard before...

Holger3.2

I assume we all talk about the same little hole in the shaft ...
here a better picture where the grease comes out.
btw, the inside bearings grease never got that liquefied, means the temperatures on the inside should be much lower than on the outside bearings.