Rebuilding Rear Brake Caliper Help

[Solid Snake]

Is it possible to rebuild the rear brake caliper, I got it off of my 84 200x and I know it doesn't work right. The piston that pushes the pads gets stuck like crazy. It's almost completely stuck. Should I take it to my honda dealer? New ones are too explensive, ebay ones all say they have problems. My clymer manual tells you how to do everything to the brakes but in the section where it talks about rebuilding it says not to do it and take it to get rebuilt or replace it (alot of help that was!!). Thanks.

[chris200x]

www.hyperparts.com has the complete rear caliper rebuild kit. Use thier search box. I've seen them on there. It wouldn't help to soak it in some kind of wd-40 or similar for a while. That may free things up a bit.

[TeamGeek6]

The calipers hang due to moisture either from outside, or absorbed in the brake fluid (or both). If the fluid is black and smells like ammonia, it has absorbed water.

Water in the cylinder corrodes the aluminum (white gunk) and binds the piston and seal. Water + aluminum --- > Aluminum oxide.

Take it apart and sand it with 600 - 1000 grit silicon carbide sandpaper and WD-40 or similar (any light oil). Sand it lightly and evenly around in circles, not long ways. dont try to get all the pock marks out unless they are very deep. If that doesn't do it, itll have to be honed.

If it has a square seal groove for the piston seal, DONT leave any gunk in the groove, itll compress the seal against the bore and youll have to do it again. Clean it out with a razor blade.

May be able to drop it in boiling water and soften the contamination, as I recall, aluminum oxide absorbs water.

Drain and flush the entire brake system to get rid of the contaminated fluid.

I just did this on a 1938 Chevy with cast iron wheel cylinders, worked like a charm.

[jeswinehart]

it is not that hard to rebuild any caliper. once you get it all apart there is a very small o-ring that in the area the small rod ( backside of the piston) slides thru ,,,, hard to get out and even a little harder to put back in.
i only mention this because the first time i rebuilt a caliper i did not notice or know about that o-ring and it was bad ,,, wich would not allow me to bleed out the air since it leaked and sucked in air into the system.

john

[sblt500r]

yup you can rebuild a caliper. i did the one in my 200x and just reused the old seals.(didn't know you could buy a rebuild kit) and just make sure you put that o-ring back in the right way. put it in wrong and i had brake fluid leaking out the back of it and couldn't figure out why.

[Solid Snake]

Ok guys, I got the caliper down to one thing left, getting the piston out of the housing. It is stuck tight, like super tight. I don't want to damage the piston with channel locks or pliers but I want to know should the piston come right out of the housing? And also the parking brake add-on, is that large bolt with the huge threads on it suppose to make contact with the little pin in the back of the housing because on mine that piece is hollow and it seems like it just threads in for no reason. Any thoughts?

[chris200x]

Well I can tell you that sometimes they are too far gone to be rebuilt.

I stripped my bleeder nut on mine so I took it to the shop. they told me it was frozen and could not be rebuilt. Then they tried to charge me $95 for a reconditioned caliper. That was like 2 months ago :crazy: So needless to say I now have no rear brakes. Someday I should go to pick it up cause there is brand new pads on there. I know that wasn't much help but I'm bored. :rolleyes:

[jeswinehart]

Ok guys, I got the caliper down to one thing left, getting the piston out of the housing. It is stuck tight, like super tight. I don't want to damage the piston with channel locks or pliers but I want to know should the piston come right out of the housing? And also the parking brake add-on, is that large bolt with the huge threads on it suppose to make contact with the little pin in the back of the housing because on mine that piece is hollow and it seems like it just threads in for no reason. Any thoughts?
the manuals say to use air pressure to pop the piston out. get the best seal you can using a air nozzle on the brakeline inlet and apply pressure to the max you can. you also might want to soak the whole thing in brake fluid for a day or so and re-try.
yes ,,, the parking brake corse thread part pushes against the small rod on the back side of the piston to engage the park brake. being so corse it don't need to be touching the piston rod to work ( but can't be a mile away either ).

john

[Solid Snake]

Oh I get it, the bolt that goes through it is suppose to actually hit the rod. I kept thinking to myself, how does this thing work it doesn't even touch that piece on the back of the piston. Maybe I'll try soaking it overnight in brake fluid, but won't that remove all the black finish that is on it? What about what teamgeek said about putting it in boiling water? Whatever I come up with I'll let you guys know. I don't see how I'll use air pressure because we have a compressor but not an attachment with any threads on it and I know I won't be able to hold the air nozzle and caliper together at really high pressure.....BUT I'M STILL GOING TO TRY!!! Hahahaha.

[sblt500r]

if you have the parking brake removed you'll see the piston sticking up. push on that to get the piston out. if it moves a little then stops, push it back the other way and keep doing that a couple of times to try and break some of the rust off the piston.

[jeswinehart]

you might try what teamgeek says ,,, May be able to drop it in boiling water and soften the contamination, as I recall, aluminum oxide absorbs water.

i really don't know about the absorbant thing but he might be on track with hot water ( instead of open flame ) and a even heat possibly expanding the body some what to allow the piston to free up a tad and pop out.

butttt ,,, i would remove the bleeder and try a good soaking in the stuff that is made to run thru it first ( brake fluid ).
i use some eletrical tape around the tip of my hose nozzle to make for a better seal and to protect the bajo bolt hole ( goofy name for that bolt that is used on brake lines ).
i have done 3 calipers like the book says and twice i had the piston "pop" out and pinch a finger so keep the fingers out of the way. once i sent a stuck piston ( 1 of 2 ) on a 350x front caliper sailing across the garage and bouncing off the walls ,,,, they tend to "pop" with the same force you put against them.

john

[Solid Snake]

GOT IT OUT!! I used a punch and hit it from the rear pin and out it came. Anyway I gotta get a rebuild kit for new seals and I'm getting the piston and the bore on the caliper honed tommorrow. Thanks for all the help guys.

[ATCnut]

The other thing to overhaul is the slide pin. I find that the pin gets stuck in the calipar.