Date: Sat, 5 Aug 2000 22:29:22 EDT
From: LHassig_at_aol.com
Subject: [E36M3] brake caliper rebuild question (was: Aaarrrrrrrrrrrgggggggggghhhhhhh!)

Folks,

OK, so I decided to rebuild a caliper. Thanks, Ron K., for steering me toward instructions for the procedure on bmwmpower.com. They were pretty good, at that! All they left out was the magic word to get the !_at_#$%^& dust boot attached to both the piston and the caliper AT THE SAME TIME!

When I went to my local BMW store to buy the rebuild kit, they had to order it for me. Hmmm, I observed to the parts person, I would think that you'd have these kits in stock. Actually, she said, this is the first one we've ordered. We don't recommend rebuilding calipers (and no wonder, I thought. The kit costs $22 and a new caliper costs $400.)

Now I know why they don't recommend rebuilding the caliper. The labor would exceed the price of a new car, and then the tech would "go postal."

I spent three hours trying and trying and trying to get the dust boot to do its trick. At this point, I feel like I've been through the rites of initiation. Does anyone have the secret that can save me from taking out a loan to buy a new caliper?

Thanks, Lee
'95 M3

Re:

>I spent three hours trying and trying and trying to get the dust boot to do
>its trick. At this point, I feel like I've been through the rites of
>initiation. Does anyone have the secret that can save me from taking out a
>loan to buy a new caliper?

Someone did post exactly that secret to the list -- perhaps you can search the archives?

As best I remember, it's something like this:

1. Attach boot to piston FIRST -- I think this is the key ....
2. Lubricate caliper well with something (brake caliper lubricant is best, #2 is brake fluid.
3. Now, bring piston/boot "assembly" close to caliper, and fit the boot into the caliper. You want to get it so that when you place the piston into the caliper, the piston keeps the boot from coming back out. Slowly push the piston into the caliper -- the better you lubed it, the easier it is to push it against the caliper/piston seal ...

Now, I have a feeling I may have done the following: pulled the dust boot over the outside of the piston and let it ride about halfway down the (polished) sides of the piston. I don't think that will "overstretch it". This keeps there from being too much "pull" on the boot and will allow you to place the outside lip into the caliper and not have it pop out immediately. Then, as you sink the piston down into the caliper bore, pull the dust boot up, and eventually it (the inside lip) will pop into place on the top of the piston.

If you must use a tool, be sure it's not at all sharp -- something plastic is good. Once I got a hang of it (and it did take a while -- I was able to do the other three in 5-10 minutes each.