Mechanics

HOW FRONT BRAKE CALIPER SLIDES?

2002 Jeep Wrangler • 107 miles

How do you get the front brake caliper guide/sliding pins on a Jeep TJ to slide freely and not stick every time they sit for a couple minutes!

P.S I'm using brand new pins, sleeves/boots, and grease.

I have tried different amounts of grease.
I have tried putting the pins inside the boots OUT of the caliper mount hole to see if the caliper mount hole was too tight and nothing changed. STILL STICKING!
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Mcjeepin
June 22, 2012.




Have you used the ceramic caliper lube? If not try that its the heat that boils out other greases. Also the sliding area is there any grooves in it?

Racefan966
Jun 22, 2012.
There are little ridges inside the rubber boot piece and the metal pin that goes inside the rubber piece is smooth and brand new.

Tiny
Mcjeepin
Jun 22, 2012.
Emery cloth the ridges a little to smooth them and then use the ceramic caliper grease and you should be fine.

Racefan966
Jun 22, 2012.
Everything slides fine and goes together good when I first put it together but when I let it sit for half an hour and come back to try to move them, it feels like the grease has acted like a glue and frozen/dried? Then when I break it free of its stuck position, it works fine again but let it sit for some time and same thing happens.

Tiny
Mcjeepin
Jun 22, 2012.
Ceramic caliper grease should fix that problem.

Racefan966
Jun 22, 2012.
You think? I'm using synthetic. Will that really make the difference?

Tiny
Mcjeepin
Jun 22, 2012.
What about silicone? I'll pick up some ceramic based tomorrow. I guess I'll try ceramic first and if it doesn't work, could I try silicone based caliper grease? (If available)
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Tiny
Mcjeepin
Jun 22, 2012.
Most people don't even understand the importance of brake grease so kudos to you for that. It doesn't sound like you have a problem. The caliper is only supposed to slide 1/4" over the life of the pads. The rubber inserts stick and bend a little when you apply the brakes, then when you release the pedal, the sleeves relax an pull the caliper toward the rotor just a fuzz to release pressure on the outer pad. The square-cut seal inside the caliper works the same way to release the inner pad.

If you REALLY want to see a sticking caliper, (and a real poor design in my opinion), look at a 1980s Ford truck with their steel inserts. Now THAT'S a caliper that won't slide.

Caradiodoc
Jun 22, 2012.
But its sticking so bad it WILL NOT "relax an pull the caliper toward the rotor just a fuzz"

Tiny
Mcjeepin
Jun 22, 2012.
Maybe my fuzz is smaller than your fuzz. You won't see the caliper move; ... Well, maybe it will twist a little if you watch while a helper works the pedal, but all you need to care about is that you can turn the rotor by hand when the brake pedal is released. If not, it's the piston that is sticking. Two things can cause that. Most commonly a ring of rust or mud has developed around the piston that is catching on the square-cut seal so it can't retract. That happens most often when the piston is pushed back into the housing to make room for the new thicker pads. I only worry about that when I can't pry the piston in with a small flat blade screwdriver before I remove he caliper. If you ever HAVE to resort to using a C-clamp, you have a piston problem.

The second cause is brake fluid contaminated with a petroleum product. You'll see the rubber bladder seal under the reservoir cap is blown up and mushy. On some models the flexible rubber hoses can become constricted too leading to pistons that won't release. You can identify either of those by opening the bleeder screw while the brake is stuck. That will release trapped fluid pressure.

That doesn't sound like what you're describing though. It might turn rather hard, but if you can turn the rotor by hand, you're okay. Keep in mind that when you're bouncing down the road, the normal play in the wheel bearings is going to let the rotor wobble a microscopic amount and that will help push the piston in and shove the caliper around. Unless I'm missing something in your symptoms or description, I don't think you have a problem.

Caradiodoc
Jun 22, 2012.

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