Compressing caliper pistons

[tom4bren]

Sorry to be on topic, but it's a good idea to open the bleeder screw when compressing the piston, so any debris in the brake fluid at the piston is bled out rather than just being forced back up the line.

How dare you un-jack this thread!!!

Actually I disagree. Unless you have a brake bleeder set up, you're likely to get air in the line when the piston reaches the end of it's compression. I'd rather have debris in the line than air.

It would be a good idea however to clamp the caliper on the opposite side of the vehicle so that as you compress the side you're working on, the piston on the other brake doesn't de-compress to the point of disengaging the guides or damaging a seal. That's why I always complete one side before I start on the other (go ahead ... ask me how I know).

[BigSwede]

Actually I disagree. Unless you have a brake bleeder set up, you're likely to get air in the line when the piston reaches the end of it's compression. I'd rather have debris in the line than air.

Yes, you would certainly want to bleed the brake lines a little to remove any air.