sticky calipers

[nightpilot]

My calipers were siezed up when I got the 82 xj. I cleaned them well. Orings looked good, rear looked perfect and new. Took out outside dust oring on front at mechanics sugg as these get gooey and stick. Put together with lots of brake fluid and nothing else and worked great.

Still when sat for a month back then front stuck. took apart and looked cruddy around where piston and caliper contact on outside. Looked like corrosion in back boot. and kind of coorosion like on fronts. can clean back boot with wd40 but it will go away on pistons.

My garage is damp which does promote mold and may promote corrosion. Thinkng about putting a little antisieze around outside of piston where it slides in and out of caliper. Dont know if the antisieze will expand rubber orings like grease or oil. Any ideas guys. any one else get this siezing for no apparent reason??

[fredintoon]

- - - My garage is damp which does promote mold and may promote corrosion. Thinking about putting a little antisieze around outside of piston where it slides in and out of caliper. Dont know if the antisieze will expand rubber orings like grease or oil. Any ideas guys. any one else get this siezing for no apparent reason??

Hi nightpilot,
hydraulic seals are usually installed with a special grease that's compatible with the seals and with the fluid.
I'd say contact a local hydraulics rebuild shop to find out what the stuff is called and if you can buy some.
A smear of that around the rust-prone areas should keep them nice without bothering the system's internal workings.

[CatatonicBug]

Personally, I would stay away from adding anything but brake fluid in there. Even the idea of WD40 makes me cringe. The one main thing to look at is the groove that the piston seal sits in. if that groove has gunk in it, that will cause the seal to press against the piston/caliper wall and cause sticking.

Take the pistons out, remove the rubber seals, and use a dental pick to clean the grooves. Rinse with brake parts cleaner (only on the metal parts) and use compressed air to dry them out. Liberally apply some brake fluid, and re-insert the seals.

Moisture in the air should not cause an issue with the calipers, as they are a sealed system. No air gets into them to cause corrosion anywhere past the seals.

[nightpilot]

guess I wasnt too clear, I read all the threads and cleaned the grooves out perfectly. Everything looked perfect. this is a wierd thing. the corrosion looking stuff was all on the outside of piston where it is exposed to air.

When i put it all back together , went together well and it worked perfectly, not too tight, etc.

then when sitting, the parts exposed to air got nasty.

I am going to check on the grease for hydraulics that fred mentioned, maybe that will help on inside to make them release perfectly with zero drag, but also maybe coating piston on outside will keep air related issues away.

Thought about the antisieze because it is made for the contact of two different materials, us it all the time on airplane motors, and it stays on a real thin coating you cant hardly get off. we use it on plugs going into aluminum heads.

[Larrym]

Right lube but wrong location

Nightpilot,

Pistons, grooves, seals, etc., are part of the "active" system which makes the pad press against the rotors. The are other parts of the system that are "passive" which are just as important.

Particularly, the friction surfaces that slide against each other on the caliper body and the "bolts" the entire assembly slides on. (Not much of a slide but it's there or in your case maybe Not...)

If you take the calipers off, clean these friction/slide surfaces, and use high temperature anti-seize on them, then you can rule out that part of the system as the likely culprit. (Wear those nitrile gloves to keep the anti-seize off your hands. DAMHIK.)

Good Hunting!!

[XSokieSPECIAL]

guess I wasnt too clear, I read all the threads and cleaned the grooves out perfectly. Everything looked perfect. this is a wierd thing. the corrosion looking stuff was all on the outside of piston where it is exposed to air.

When i put it all back together , went together well and it worked perfectly, not too tight, etc.

then when sitting, the parts exposed to air got nasty.

I am going to check on the grease for hydraulics that fred mentioned, maybe that will help on inside to make them release perfectly with zero drag, but also maybe coating piston on outside will keep air related issues away.

Thought about the antisieze because it is made for the contact of two different materials, us it all the time on airplane motors, and it stays on a real thin coating you cant hardly get off. we use it on plugs going into aluminum heads.

Be certain the spooge hole ( brake fluid return hole ) in your master cylinder is not clogged, also check that you don't have a brake hose, or hoses with a blockage.

Don't put anti sieze or any other lubricant with any kind of petrolium substances in it anywhere near any of the rubber parts of the brake system.

It will cause them to swell and distort and you'll have a huge expensive mess and head ache on your hands.

[TomRodgers]

I.D. glide. safe for rubber parts..