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Stuntmanmike1977

Original poster
Member
Nov 21, 2021
84
Sanford, Maine
Hello everyone. So I attempted to do my brakes today. Let's just say I spent 3 hours on the rear only. The problem was not only were the caliper pistons a pit of rust but the driver side rear caliper piston didn't and couldn't go in all the way even with severe pressure. Aren't they supposed to be flush with the caliper body? Well, had to take the shims off to barely get the caliper over the pads. Wheel still turns free and seemed to bed in fine. Stops without noise but why would the caliper fit fine on the passenger side and not the driver? Also, noticed after pushing the pistons back in the bleeder screws and caps had fluid in them. Still have good pedal and nothing wet or dripping back there. What would cause the fitment issue?
 

Stuntmanmike1977

Original poster
Member
Nov 21, 2021
84
Sanford, Maine
Hello everyone. So I attempted to do my brakes today. Let's just say I spent 3 hours on the rear only. The problem was not only were the caliper pistons a pit of rust but the driver side rear caliper piston didn't and couldn't go in all the way even with severe pressure. Aren't they supposed to be flush with the caliper body? Well, had to take the shims off to barely get the caliper over the pads. Wheel still turns free and seemed to bed in fine. Stops without noise but why would the caliper fit fine on the passenger side and not the driver? Also, noticed after pushing the pistons back in the bleeder screws and caps had fluid in them. Still have good pedal and nothing wet or dripping back there. What would cause the fitment issue?
And, I have to take it apart again to adjust the emergency brake
 

TollKeeper

Supporting Donor
Member
Dec 3, 2011
8,053
Brighton, CO
I could have sworn that the rear/front caliper pistons were phenolic resin, they shouldnt rust.

Wondering if the rust you saw was cast off from the disc brake pads?

If the piston wont go flush, there is something internally, that is causing issue. Might be time to replace the caliper.
 
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Mooseman

Moderator
Dec 4, 2011
25,344
Ottawa, ON
Even with phenolic pistons, they can bind up due to the seals or the piston swelling. If they won't go flush or are leaking, time for a replacement.
 
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