Caliper Piston Leaking

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rose359

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My son bought a 1998 1500 in need of brake work. The right front inboard pad and rotor wore so thin that the caliper piston came out to the point that the seal is leaking fluid. Never seen that before. Do you think the caliper will be ok once the piston is pushed back in? Do I need a new seal or new caliper? Thanks
 

HotWheelsBurban

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Best thing would be to replace both calipers. Also the hoses to them, and of course a set of pads and the rotor if it's worn down that much. The parts are not too expensive and it's worth it to have good brakes.
I say this because on my '99 Burb several years ago, the brake hose on the right front collapsed internally and locked the caliper up. This may have happened on your truck as well. Often if one side wears a lot more than the other side, it's this, or failure of the hold down parts or fasteners.
These parts need to be installed properly, clean and lubricated with the correct brake lubricant.
You could pull the caliper and put a rebuild kit in it, replacing the seals and rubber bushings on the guide pins, and cleaning and honing the caliper bore and piston. But you still have to bleed the system, and the complete caliper is relatively inexpensive compared to most cars.
 

Schurkey

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Most of my vehicles have had the pistons pushed out of the calipers, the square-cut seal removed, everything cleaned-up, and then reassembled with the original seals. Slider pins/sleeves cleaned-up and lubed, bleeder screw cleaned-up with a touch of anti-seize on the threads.

I have never had a problem doing this. That said...it's certainly NOT recommended in any service manual; and may not work on a caliper that's already leaking. Mine were all fluid-tight, but the pistons were getting "stiff" to move.

Iron calipers are easier than aluminum calipers, and single-piston calipers are significantly easier than multiple-piston calipers. Aluminum calipers generally need the corrosion dug-out of the seal groove(s). Iron calipers tend to be OK in the seal grooves once the sludge is washed out.

It is absolutely easier to pull out the "Visa Wrench" and just buy rebuilt or new calipers. OTOH, I have zero dollars invested in this process aside from the cost of my time, and "shop supplies"--caliper grease, electricity and wear on the wire wheel, some Brakleen, rags, etc.

Example of crusty rubber square-cut seal from my K1500; with some of the scuzz scraped-off with a fingernail. I make a special point of checking the rubber for cracks/deformation. Despite the age and mileage, the rubber square-cut seals haven't been a problem for me. I have had some torn dust-boots which require a "seal kit" to replace.
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Caliper, piston, square-cut seal before cleaning. I've been lucky with caliper pistons--they're not rusted or have flaking chrome. Any defect below the dust seal groove and they're history.
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...And after cleaning. Piston lubed, and shoved past the dust seal and square-cut seal, but not pushed all the way into the bore:
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Caman96

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For $125.00 you can get brand new Raysbestos Element3 calipers and pads. To me your time(=money) to rebuild/repair parts, and then what do you end up with? Maybe improved older parts? Brakes are pretty important and he is your son.
 

rose359

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For $125.00 you can get brand new Raysbestos Element3 calipers and pads. To me your time(=money) to rebuild/repair parts, and then what do you end up with? Maybe improved older parts? Brakes are pretty important and he is your son.
My son is a grown-ass man, but needs to minimize the parts cost. He does get a 10% military discount on parts. As the old man, I can offer some expertise, the tools, and my sunflower propane heater; the temperature is negative here in Minnesota this morning.

Thanks all for your inputs.
 

rose359

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Once the caliper was free of the rotor, the piston fell to the floor. Piston had been bearing directly on the rotor for a bit.
 

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Schurkey

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The right front inboard pad and rotor wore so thin that the caliper piston came out to the point that the seal is leaking fluid.

Piston had been bearing directly on the rotor for a bit.
You're saying that the brakes were piston-on-rotor, then someone did a "brake job" and crammed a new pad back onto the already-damaged caliper piston (and maybe the already-damaged rotor)?

And when THAT wore out, the caliper started leaking?

Woof. Someone needs to have their fingers broken with their own wrenches.

Yeah, you need a rebuilt caliper or two, along with rotors and pads. Maybe brake hoses. At least the brake fluid will be fresh when you're done. (Flush the rear brake fluid, too.)
 

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Woof. Someone needs to have their fingers broken with their own wrenches.
Lol, I did an s10 where once I pulled the wheel off, I was looking at the fins that should've been internal to the rotor but the outer face was comepletely ground off. They drove it till it didn't drove no mo'. Sometimes you need to learn to be a quitter and stop driving the thing.. Not sure how the wheel never locked up on them.
 
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