Nathan asks:
> ...when reinstalling the pistons into the housings,
> the center pin is REALLY tight on the piston.
That's known as the retractor pin, I believe. Here's how it works:
Inside the piston is a spring mechanism. It's a tight friction fit over
the pin mounted in the center of the caliper body. The spring allows
a small amount of 'forward' movement when the brakes are applied,
them pulls the piston back just a smidgen (technical measurement)
to release the brakes. As the pads wear and the piston moves out
further, the mechanism slides up the posts. Thus, the pads are always
able to be pulled back by a fixed, small amount.
Once you shove the assembly together, chances are you'll need
pressure to pop it back out. I've used air in the past, but have found
that fluid pressure is MUCH more controllable (jerry-rig the caliper
up to a master cylinder; pump the master and pop the piston. Messy!
But with air, you 'shoot' the piston with sometimes nasty results!)
The rebuild kit contains a weird red grease that I believe is used
to lube the seals and piston assembly. I also recently found a 'brake
lube' that is used during rebuilding and mixes with brake fluid.
Little 4 oz squeeze bottle of clear liquid.
-- John
John F Sandhoff sandhoff@csus.edu Sacramento, CA
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