How do I know if calipers are bad

[jim-milwaukee]

2005 Impala. 52k. 4-wheel disk. When braking, I notice a prerrt heavy pulsation. I figured I had a warped rotor, and was planning on replacing the rotors and pads in the next month or so.

I recently had my car in to flush the cooling system, and when I picked-up the car, the mechanic left a message for me that he thought the rear calipers were bad and would need to be replaced. Does not seem right, I need to follow-up with him regarding how he came to that conclusion.

As a general rule, how would I know if a caliper is bad?

On braking, there is no pull, simply a pulsation.

I would have guessed the front brakes to wear faster than the rears.

Plan on pulling off the wheels to get a good look this weekend. Any advise on what I should look for? Sorry for the dumb question, I'm trying to learn ....

[fruzer31]

that pulsation your are feeling is the rotors, which you said you planned on replacing so no biggie, i think i would change that and see cuz why buy a caliper if its no needed. And if the pulsation is there get new calipers. But thats just what i would do.

[Kemi]

Jim,

The pulsation is almost surely in the rotor(s). If you feel the pulsation in the steering wheel, then it's from the front rotors. If not, then it's probably in the rear ones.

When you replace the rotors, I would change the pads if they are fairly worn. Why do the job over again later? Also, change the metal clips/springs on the caliper bracket. Many high quality pads will contain these clips but if not, you can buy them. They are called brake hardware.

(When you replace the brake hardware, use a grinder or file to remove some of the rust on the caliper bracket where the hardware clips go. This allow the pads to fit nicely and prevents them from getting bound up)

As for the calipers, you said the car is not pulling and that's a good sign. Check the following:

Obviously, make sure they are not leaking.

Check the rotors for a bluish color or a burnt smell or appearance. You can also check the pads to see if they've been 'cooking'. Sometimes a caliper piston will lock intermittently.

Make sure the calipers slide easily on the guide pins/bolts. If they are frozen it's probably best to replace them. If not, remove the guides and apply a silicon into the bore on the boot. If they move, but move tightly, you can remove the guides and the boots and clean the rust from the bore with a grinder. You will probably have to replace the boots but they're accessible.

When you compress the caliper piston, make sure you open the bleeder valve to let the old fluid out, rather than pushing it back into the system. It makes it easier too, although you will probably have to bleed the brakes when your done.

Good luck!