caliper seal acting funny

[bowlofturtle]

I was doing rear brakes on a fusion today. They have the twist type rear piston. I noticed when i twisted it in the seal around the piston was going along for the ride, so i had to go forward and backwards to play with it and in the end it seated right fully compressed.

Now the other side, it didn't go back so the rubber boot unsealed itself from the caliper and i had to tuck it back in with a pick.

Which was is the normal way? you have to twist the piston in so obviously it has to spin but the boot isn't suppose to unseal itself right? So the first caliper was the right way things should be. I made like a full turn and saw the boot twisted and turned it back about 1/4 and the boot went back to normal and redid that step.

 

[CharBaby]

To me, it does sound as though you had some issues with the piston seal but, fixed them with a little bit of work.

So, are you satisfied with the end results or are you still having "non sealing issues"?

Even if the seal moves around while your turning back in the caliper piston, you should be OK! Having the seal "TWIST" isn't the best thing to happen but a little brake lube(I like PERMATEX Black) might help things to slide better.

The piston seal is to help prevent dust/dirt from getting in behind the piston and contaminating the brake fluid, ABS sensors etc. As long as it's not completely distorted, you'll be fine.

Nice Job!

 

[mechtech2]

The dust seal? A little lube would have cured that. [it should remain stationary]

 

[bowlofturtle]

i'm pretty happy with the results. SLIGHTLY a bit more work and annoying. I had to extract the piston out like almost fully to tuck the lip of the seal back in. Having never rebuilting a caliper i didn't have a clue to get the piston back in had i got it all the way out so that was a fear. I thought about lube but i didnt know what was good for piston seals. All i had was Napa's SLYGLIDE for the pad backings, PB blaster for the bleeder screw and brake clean. Non of which i wanted to use and possible destroy the seal but i thought really close about the SLYGLIDE.

Overall i knocked out the rear brake job in about 80 minutes from pulling in to my garage to start of bedding in the brakes.

So the seal SHOULD OF remain stationary, i see.

 

[CharBaby]

Yep, the SYLGLIDE would have been the ticket for lubing the rubber seal. The piston/seal would be pushing against the back of the pad where you had applied Synglide to the back of the pad anyway. So, in the future if you have issues with this seal, you'll know just what to do