Do I need a new Brake Caliper?

[davegostelow]

Hi,
This is my first posting to the forum, I found a lot of useful stuff in here already.

I have had a front offside brake binding on my Felicia, sometimes its bad sometimes its not binding at all. I worked through some possible causes and eventually decided it was the piston sticking in the caliper. I took the caliper off and got the piston out (which was not easy) to take a look. Inside I found that rust had crept in from the outside, past the outer rubber seal and onto the thin bit of cylinder metal before the fluid seal and this rust must have been gripping the piston. I guess the outer seal had failed to cause this. It didn't get onto or past the fluid seal, and there was no fluid leaks either.

I have sanded off the rust with wet/dry paper and reassembled the caliper, and it is now working perfectly, no binding at all. How long for I don't know.

Question: Do I need to replace the caliper or is the 'repair kit' of new rubber seals adequate? A new caliper is quite expensive while the repair kit is cheap.

Would de-rusting and painting the outside of the calipers stop this rust creeping into the cylinder bore in future? I thought that the only reason brake gear is painted is to make it look good through alloy wheels. Presumably you have to be careful not to get paint onto the rubber, piston, or bleeding points?

Dave.

[ap0gee]

Bloody hell! Nothing like a making your first post a toughie like that!

I'm no car mechanic, but I've been happy to ride round on a pushbike maintained by myself at somewhere approaching car speeds - so I guess your question of "is it OK?" really depends on how confident you are in your own abilities. If it was just surface rust you removed, and you rustproofed it adequately and reassembled everything correctly, then I don't see any reason why you'd need to replace the whole caliper. Then again, it's your brakes were talking about...

Anyway, welcome to Briskoda!

[bobob]

A repair kit of new seals should be all you need
had to do this loads of times to various cars in the past

[harryhill]

did you check the sliding pins before dismatling your caliper? These seize easily and cause binding

[davegostelow]

Yes I checked the sliding pins. Thats what I originally thought might be the problem. They had a 'bouncy' free sliding movement but I took them out and cleaned them anyway. Didn't even have any scoring or ridges on them.