Date: Sat, 5 Aug 2000 22:29:22 EDT
Subject: [E36M3] brake caliper rebuild question (was: Aaarrrrrrrrrrrgggggggggghhhhhhh!)
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?
Date: Sat, 05 Aug 2000 20:26:20 -0700
From: "Andrew E. Kalman" <aek_at_netcom.com>
Subject: [E36M3] Brake Caliper rebuild answer (was: Aaarrrrrrrrrrrgggggggggghhhhhhh!)
>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
As best I remember, it's something like this:
- Attach boot to piston FIRST -- I think this is the key ....
- Lubricate caliper well with something (brake caliper lubricant is best,
#2 is brake fluid.
- 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.
Andrew E. Kalman, Ph.D. aek_at_netcom.com
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