1 Checking for stuck / frozen caliper pistons Sun Apr 22, 2012 10:02 am
C_Mick
Silver member
While the 75 was stored in my garage the reservoir of the rear master cylinder disintegrated leaking brake fluid all over the place and giving the RHS footplate a severe case of Japanese frostbite. The replacement m/c reservoir should reach me tomorrow, but I wanted to check before filling up with brake fluid that the caliper pistons were working OK. Curiously the pistons were in the pushed fully into the caliper position and I was trying to think of a way to see if they would move freely. I'd read in a post on this forum that it works to use an air line to drive a piston out of its bore in the caliper. That prompted me to think of using my car tyre inflater which is is driven via a 12V power socket.
It worked very well and on a setting of approx 3.5bar the pump applied enough force to the disc pads for me to be satisfied that one or both pistons are not frozen. I had already checked to see if any brake fluid had leaked past the caliper seals, but fortunately it hadn't.
Chris
It worked very well and on a setting of approx 3.5bar the pump applied enough force to the disc pads for me to be satisfied that one or both pistons are not frozen. I had already checked to see if any brake fluid had leaked past the caliper seals, but fortunately it hadn't.
Chris
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Two wheels good...Four wheels bad...