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Dragging Caliper


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My son's '03 STS has had a problem with the right front brake caliper dragging. We've replaced pads, rotors, right front caliper and hose and the brake master cylinder. We have a good pedal but the right front caliper is still dragging on the rotor.

He's home now trying to solve his problem and just called me (at work) to tell me that he had a very difficult time getting the caliper off of the pads/rotor. What he describes sounds to me like high residual fluid pressure holding that piston tight to the rotor.

I would thin the next thing to look at is a/the proportioning valve, metering valve, ABS pressure dump valve (if there is such a thing?).

Any help or advise is greatly appreciated.

Thanks,

Roger

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I would have thought it was a bad hose, Ill check my manual to see what can cause this.

What kind of brake fluid are you using and was it fresh when it was put in?

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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Thanks.

Hose is new with caliper. Fluid is new Valvoline synthetic DOT 3, 4.

I just spoke to junior; he's called the Caddy dealer in Tampa and they advised him to bleed the brakes with the

key on to turn on and cycle the modulator valve. Dealer tells him one of the solenoids in the valve needs to be cycled. Makes sense to me... We'll try it when I get home and report results to the BB.

This all started last week when he wanted to change pads (the pads had a few miles left in them). I didn't feel like opening the front bleeders and potentially bleeding the brakes at 10:00 at night so I told him that he could push the caliper pistons in but something like this could happen and that he would make the call...

Herein lies a lesson for us all.

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Are the pins that the caliper slides on clean, rust free and well lubed? If not, clean them. If they are rusty you may get away with wire wheeling them, if not then replace them. Be sure to ONLY use silicone brake grease.

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Are the pins that the caliper slides on clean, rust free and well lubed? If not, clean them. If they are rusty you may get away with wire wheeling them, if not then replace them. Be sure to ONLY use silicone brake grease.

Good Point, I have seen those sliders lock up badly

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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"Are the pins that the caliper slides on clean, rust free and well lubed? If not, clean them. If they are rusty you may get away with wire wheeling them, if not then replace them. Be sure to ONLY use silicone brake grease."

Excllent point. They're both new now. The upper pin was very badly corroded, other three were clean, and we replaced all four (both sides) with new. We actually had to drive the upper pin out with a pry bar and a BFH and I mean we had to really beat that sucker out. Tonight we went through everything once again. Bled the brakes on that side, cycled the ABS (panic stops on a wet road). That caliper is still hanging up but not as badly as originally. I am going to take it all apart again this weekend

and really look at that caliper bracket. Has me stumped but I honstly feel we are close to solving the problem, which I feel is that bracket and pins. the level of corrosion on that pin had me concerned and I think that is where the problem may be...

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I dont know if the 97 is the same as the 96, but if there are rubber bushings in the caliper you should idealy replace them, at the very least remove them and remove the rust that gets behind them

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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Junior cleaned the holes in the bracket, but I'm going to do it all again, very exacting and as thorougly as possible clean the pin bores in the bracket, really dig the crud out.

Edited by MrEldo97
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"Are the pins that the caliper slides on clean, rust free and well lubed? If not, clean them. If they are rusty you may get away with wire wheeling them, if not then replace them. Be sure to ONLY use silicone brake grease."

Excllent point. They're both new now. The upper pin was very badly corroded, other three were clean, and we replaced all four (both sides) with new. We actually had to drive the upper pin out with a pry bar and a BFH and I mean we had to really beat that sucker out. Tonight we went through everything once again. Bled the brakes on that side, cycled the ABS (panic stops on a wet road). That caliper is still hanging up but not as badly as originally. I am going to take it all apart again this weekend

and really look at that caliper bracket. Has me stumped but I honstly feel we are close to solving the problem, which I feel is that bracket and pins. the level of corrosion on that pin had me concerned and I think that is where the problem may be...

To thorougly inspect the caliper mounting bracket you will have to remove the bracket. If there was the kind of corrosion you described on one of the caliper pins, there might be (?) similar corrosion on the caliper mounting bracket-to-hub bolts or on the bracket-to-hub mounting surfaces.

If you elect to go that far, I would suggest an additional step as a double check. Do the indicated cleanup or parts replacement and assemble the bracket to the hub and mount the caliper on the bracket using the proper torque values -- but leave the rotor off. That will allow you to check for proper caliper freedom of motion. It's double the effort but there is no other way to be 100% certain the caliper is free to slide.

Jim

Drive your car.

Use your cell phone.

CHOOSE ONE !

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Good idea and I will do exactly that when I get home tonight.

My Memorial Day weekend is going to be busy with car work - gotta get Junior's ride squared away, the Eldorado popped a leak in a radiator header tank so new radiator this weekend (already bought), oil change in my XJS and the pool filter pump motor crapped out yesterday... :rolleyes:

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I dont know if the 97 is the same as the 96, but if there are rubber bushings in the caliper you should idealy replace them, at the very least remove them and remove the rust that gets behind them

Those rubber bushings are very important. Make sure you use only silicon-based grease, because petroleum-based one will destroy the rubber bushings.

The saddest thing in life is wasted talent

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If you had to drive those pins out with a pry bar and BFH, there is no doubt that was your problem. That will eat up a set of pads in nothing flat.

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Thank you gentlemen for your encouraging words.

The bracket was the problem. I got into it with a 9mm ream I have (great for Alfa valve guides).

The crud in both bores was "illuminating". Thorough cleaning, new boots, new grease; took it for a drive and problem solved.

Junior can't wipe the smile from his face. Sux to be 25; own a real nice Caddy and have your wings clipped.

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You are welcome. You were all encouragingand our experience can only help someone else in the future.

I was very surprised at the fossilized crap that came out of the bracket bores - I'd never seen that level of corrosion before.

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Thank you gentlemen for your encouraging words.

The bracket was the problem. I got into it with a 9mm ream I have (great for Alfa valve guides).

The crud in both bores was "illuminating". Thorough cleaning, new boots, new grease; took it for a drive and problem solved.

Junior can't wipe the smile from his face. Sux to be 25; own a real nice Caddy and have your wings clipped.

Glad you got it fixed, it is amazing how much corrosion gets under the boots... Hey that was a LOT easier than worrying about the ABS hanging up..

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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To be sure. His car only has 90k on it and I didn't think it was the ABS. We threw it into ABS mode in a pouring rain Tuesday night and the ABS worked fine. And I told Junior that it had to be that bracket...

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I remember spending some time cleaning those holes out as well.... I only had to soak them with brake parts cleaner a few times and wipe out with a rag on the end of a screwdriver, but it was pretty nasty down in there.

Glad the fix was that easy.

Jonah

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