where is weak link of quick cv boot

so what makes quick cv boot not work? is it the seal? the material? what is the mechanism of failure?

Reply to
Philip5malin
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it's the glue joint. it doesn't work.

nate

Reply to
Nate Nagel

The boot is split so dirt can get in easily. They don't seal very well IMO. Plus usually being universal they don't fit properly also allowing dirt to get in.

Reply to
m6onz5a

Philip5malin skrev:

Have you tried a thick plastic bag and a few zip ties? I've fixed an inner boot on my BMW that way, the bolts holding the axle are rusted stuck so I can't get it off, and it's been holding up several months. The winter will be the real test though, so we'll see, but it's definitely better than nothing...

Ulf

Reply to
Ulf

are those the infamous cheesehead/triple-square CV bolts? make sure you have the right tool; you might want to have a couple after you strip a couple bolts. Also gentle heat may help (I ASSume that this is a flange where you can see the exposed end of the threads?) Worst case you can break/grind the heads and then with the axle out remove what's left by vice grips/heat or drilling/retapping.

The funny thing is, once you've replaced the axles, you have to retorque a couple times after you have them in there; they like to back out when the threads are finally clean, even after torquing to spec. (my observations are based on working on VWs and Porsches but IIRC BMW CVs look about the same.)

nate

Reply to
Nate Nagel

forgot to mention, clean the heads well with carb cleaner and a paper clip before you even start. Dip your tool in valve grinding compound (your triple square, that is...) and set it well into the bolt head with a hammer. those recesses like to fill up with oily muck and they'll strip if you don't have full engagement.

I don't know if you have enough room to use a "bolt-out" if they do strip or not, but I have removed similar bolts with them (VW supercharger bracket mounting bolts) with surprising success.

nate

Reply to
Nate Nagel

I was lucky with the first boot I tried of this type, and thought it was a trend. In later applications, I found that, no matter how attentive was to the method of installation, they did not hold up well at all.

Mostly, the glue joint fails.

Reply to
HLS

In many cases the weak link will be the method used by the person fitting the boot. Unless the glued joint is made very carefully the joint is likely to fail later, and it's difficult to make a sound joint when you're working in a dirty/greasy area. Just a smear from your fingers can be enough to ruin the joint.

I used this type of boot on an elderly Mercedes (both sides of the back axle half-shafts), and the boots were still OK about four years later (they could still be OK as far as I know, as I sold the car).

Method I used was to remove the old boot and clean the area as carefully as possible. Then wrapped round a clean polythene bag to cover the shaft, and taped both ends. This provided a clean area where I could assemble the new boot. Next, washed my hands again and assembled the boot over the polythene covered area, made the glued joint, went away and left the joint to cure for the prescribed time.

Finally, cut away the polythene bag with scissors, placed the boot into position, added the special grease and tightened the sealing bands.

I had heard negative comments about using these type of boots but thought it was worth trying, instead of having the disassembly hassle required in using the proper boots. Was pleasantly surprised, and I would not hesitate to use this type of boot again.

Cheers,

John S

Reply to
John S

I've done only 3, one being a screw-together boot that held up for at least a couple of years, the other 2 were glued-together, one a soft one, the other a hard boot I expected to fail quickly but lasted at least 6 years. I was very careful about keeping the glue line completely clean, and I left the car jacked up 24 hours with the boot not flexed at all. Keep the boot warm with a lamp if it's below 70F or the glue may take days to cure. For some cars, removing the axle and installing a conventional boot isn't that difficult, and conventional boots can cost half as much.

Reply to
do_not_spam_me

You are exactly right about installing a conventional boot.

There is also a boot which is one piece and can be stretched and installed over the joint, etc. Takes the machine to stretch it, but can save a lot of time and failure.

Reply to
HLS

Thanks for all the good advice. The bolts are hex socket, if that makes a difference. I've decided to give it another shot now that I remembered we have an air impact wrench at work. Not sure why I didn't think of it the first time, since I've used it at every wheel change, including last weekend when putting on the snow tires on the BMW...

Ulf

Reply to
Ulf

Thanks for all the good advice. The bolts are hex socket, if that makes a difference. I've decided to give it another shot now that I remembered we have an air impact wrench at work. Not sure why I didn't think of it the first time, since I've used it at every wheel change, including last weekend when putting on the snow tires on the BMW...

Ulf

Reply to
Ulf

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