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Re: piston wont retract!!!

Posted by shinyribs on Aug 26, 2012; 12:12am
URL: http://vintage-and-classic-hondas.81.s1.nabble.com/piston-wont-retract-tp4027968p4027979.html

I just did a caliper today and the piston did not want to move freely in the bore. If installed it would not have retracted either. I sanded the inside of the caliper where the pad rides( Not the piston bore)until it would move freely. A thin coating of silicone grease will help a piston retract down the road. Advance Auto sells a good silicone grease,non-melting,for about $7 a tube. Works good in a lot of other places,too.Handy to have around.

These pistons only retract a very small amount. Any resistance at all will cause it to stick. The rubber piston to caliper seal is what actually causes it to retract. The groove that the seal goes into is machined with a very slight taper that cocks the seal slightly.That cocking causes the seal to "bind" sort of and gives it the ability to retract.Very important that that groove is clean for it to work properly.

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