Caliper questions.

[The Glademister]

Taking a hard look at my rear calipers...

Is there a inexpensive way to bench test calipers?

If you apply pressure with brake fluid obviously the piston should extend but without applied pressure should it retract?

What areas should one lubricate after installing fresh pads? I noticed that the caliper doesn't "float" easily.

Thanks.

[Icey1174]

Take the caliper right off. You will see where it slides back and forth. You can grease the sliding area up. Don't use so much grease that it will end up on the rotors and pads.

They will extend under pressure but they don't really "retract" with no pressure. The lack of pressure and the movement of the caliper allow it to retract enough for the rotor to spin freely. If you have the tire off, the caliper on, you step on the brake pedal then release it, you will see that the pads are still reasonably tight on the rotor with no pressure on the brake system. You will be able to turn the wheel by hand and should become easier to turn the more you turn it as it is opening up the caliper.

After the calipers are on the car for a while they should still move, but they will not move quite as freely months (or years) later then when they are cleaned and freshly greased.

Do you suspect a problem with the rear calipers for some reason?

[The Glademister]

Originally Posted by Icey1174

Do you suspect a problem with the rear calipers for some reason?

Thanks for the reply Icey. The DS rear wheel was hanging up and getting really hot. I thought it was the parking brake but after recreating the condition, pulling the wheel off and inspecting - it's actually the caliper. The pads in that one are toast so tonight when I get parts I plan on...

Cleaning the both rear rotors really well (the calipers are off).
Installing the pads and lubricating the "float" areas and the retaining pins.
Install the calipers, seat the pads and test drive.

I studied up on disk brakes yesterday on Wikipedia. There was a really detailed and technical link that others here may be interested in...

StopTech : Balanced Brake Upgrades

According to the writer there are several reasons someone mistakenly would believe their cars rotors are warped. Unless plainly visible when rotating the hub - I think a using micrometer is the only way to be certain.

[Icey1174]

There is a good chance you may need a new caliper. I had a frozen caliper in my cargo van. I could not compress it with a c-clamp. My inside pad was worn right to the metal. New caliper, pads, and greased slide pins and all is well.

[The Glademister]

Originally Posted by Icey1174

There is a good chance you may need a new caliper. I had a frozen caliper in my cargo van. I could not compress it with a c-clamp. My inside pad was worn right to the metal. New caliper, pads, and greased slide pins and all is well.

That caliper is probably o.k. I was able to push the piston in and remove the pads - no problem. I've actually got backup calipers in a slightly less desirable condition. I cleaned those up last night also. One has a frozen bleeder that can be extracted if needed.

[Icey1174]

Grease the slide section, clean them up good, put the new pads in and you should be good to go.

[John_AZ]

Here is a picture that might help.

Use a wire brush to remove rust and oil/dirt buildup on all lube areas of the caliper prior to lube.

[The Glademister]

Yep, that did the trick! New pads, lube the rub points and thoroughly clean the rotors. That DS must have been binding because the caliper wasn't floating and deposits on the disk surface.

[racer951y]

Originally Posted by John_AZ

Here is a picture that might help.

Use a wire brush to remove rust and oil/dirt buildup on all lube areas of the caliper prior to lube.

I know what parts store you shop at use to be a manager at one of those moved over to the competition about 6 months ago. Also I need to down load a photo off my phone but had a guy bring in a rotor that at first i thought was a funny looking drum till I saw the remains of the disc on the outside. his caliper froze on his work truck and he did not know till he was doing a brake job and found the caliper in pieces and no rotor left at all just the hub part

[John_AZ]

I worked at Checker Auto in Tucson for a couple of years when I was in school (UA/Pima CC). Passed the polygraph every year! Now I shop AutoZone for fluids and Jeep parts even though Checker/OReilly is closer.