Hi, Dave --
1. Remove the caliper.
2. Remove the brake pads/shims, etc.
3. Use air pressure to remove the pistons from the cylinders. Be very
careful when you do this because they come out with some force. Keep your
fingers away from the pistons. If they are rusted, you will probably have
to work them in and out with penetrating oil/C-clamp/air pressure to loosen
them enough to come out.
Use a C-clamp to prevent the INBOARD piston from moving while using air
pressure to force out the OUTBOARD piston first. Pad between the two
pistons with something like one ply of a thick towel. You want the piston
to be padded as it comes out to prevent damage, but to be able to clear its
cylinder. Remove the outboard piston first (the one AWAY from the brake
line/air pressure port), because without it in place, you can't stop the
leakage of air pressure enough to force out the inboard piston.
4. Clean pistons and cylinders thoroughly. If the pistons are pitted by
rust, you might want to consider replacing them.
5. Install the O-ring seals in the piston. If the cross section is
slightly tapered, the large side goes on the piston toward the bottom of the
cylinder.
6. Install the pistons in the cylinders. Make sure they get started in
straight, and not cocked. Once started, they can be forced into the
cylinders with a C-clamp. After all seals are installed, push the pistons
all the way down into their cylinders. This gives clearance to install the
brake pads, etc.
7. The outer dust seals are a little tricky to install since the clearances
are so tight. As I recall. you get the seal lip on the side toward the
cylinder into the piston first, then work the outer lip into the caliper
housing as you push the piston in. Perhaps someone else can give you a
better description of that, since it has been a while since I did it.
Steve Byers
Havelock, NC USA
'73 Midget GAN5UD126009G "OO NINE"
"It is better to remain silent, and be thought a fool
than to speak, and remove all doubt" -- Mark Twain
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