So I had a brand new cv boot rip on the dyno last sunday as some of you know.
Someone on antoher forum replied to my torn cv boot with “dont you know about the zip tie trick”?
Well this led me on a google easter egg hunt. Turns out that lots of road racers do two things with their cv boots. One, they put zip ties or string between each valley on the boot to keep it from expanding due to the centripetal force of the grease. Two, they vent the boot at the small end with wd-40 straws etc.
Like this:
I also found that DSS offers a “road race” option for thier axles where they use a stronger boot and also add a vent to them to relieve pressure.
Im 99% convinced this is what happened to my boot. It expanded enough from the speeds and the grease and contacted either the motor mount itself or the bolts that hold it to the body.
Anyway, I cant believe that no one I know has heard of this before. ( I still need to talk to my road race buddy but hes testing at the Glen today).
But what the hell, how have I never heard of this before??
It happens. I’ve seen lots of BMW’s pull the stub out of the diff once they get a bit of mileage on them and the pressure builds up at the track. WD40 straw is the common fix.
I talked to a buddy of mine this afternoon who knew about the straw deal too. He said the company they got the docs Z axles from said to use them in the assy manual (I forget which company, but apparently they come ungreased and unassembled).
I have not had a issue on any of my cars either. On my cars there is nothing around the boot for it to contact so that might be why, and my car will only get to 100mph or so.
Ive never had a problem either. However, my previous axles have all had the stiffer harder plastic boots. This particular axle was new and had the really soft rubbery boot on it. Plus Im willing to bet whoever rebuilt it used WAY too much shitty grease (it was quite thin, probably not even the right stuff). I think this all added up to the boot ballooning up and contacting the motor mount bolts / bracket.
The boot sits right under the bracket where all the grease is splattered on.
How full did you have the boot? You can run just enough to make sure the joint has some jam and call it a day. If you FILL the boot, it’ll be awesome to watch fail.
