The rear calipers are aluminum and the pistons are steel, (basically good for the life of pads due to corrosion inside the caliper). The brackets are cast iron, the guide pins are steel, and they seize in the brackets about the same time the pads wear out. Sounds like it's time to do the job the right way. Reman calipers with the brackets and hardware, new pads, (the ones on there now have been overheated and they're trash). As Kyle mentioned, probably be a good idea to replace the flex lines too. FYI, some caliper rebuilers use phenolic pistons, a much better choice to reduce corrosion inside the caliper.

 

And, yet again, another problem I had with my '00 Jimmy. Caliper pistons seized, then fried my brand spankin' new $65 premium NAPA brake pads.

I screwed around with them a million times. Popped the pistons out, cleaned them & removed all the seals & cleaned those ... reassembled .. then one side would lock up. So then I worked the piston back and forth with a C-clamp a bunch of times, and that cured it ... for 3 days. Then both locked again. If I was to keep that pile, I'd have just replaced the calipers.

This was right around the time I got the 16th check engine light in 2 years - a P0300 that made me throw in the towel. Now, the Jimmy is my avatar , it's parts are all over the country, and it's engine is in our '89 S10 Blazer.

 

Yep ! It was the caliper. replaced both on the weekend and everything is fine now. Thanks to all for your help. I do have one more question. I've had this 99 for about 7 years now and it has always seemed to have "soft" brakes. Not "squishy" but just sort of soft. Is this normal? I bled them after installing the new calipers. No abs or brake light comes on and the truck stops just fine.

 

There should be a bit of travel, if you are stopping with no problems, I would not be concerned... Did they become softer after changing out the calipers? Mine was like a different truck once I did mine.

 

No change at all after brake pads and new calipers. I'm not really worried, the truck stops just fine. I was just curious if any other owners have this soft feel about their brakes. I was thinking it might get harder after the calipers were put on and thought I'd ask. Thanks for the reply!

 

I always felt the Jimmy's brakes felt soft compared to the older vehicles I usually drive. Also, sometimes you'll get just a little air bubble in there that will do that. Have someone work the brake, and crack the bleeders one more time just to see if it helps at all.

 

My pedal feels soft, I've just had the bleed nipples replaced as they were badly corroded and the fluid changed as it was filthy but it still feels soft, better than it was but not great. Stops OK. I am wondering if my master is dying as it feels very soft first couple of pumps in the morning and then fine afterwards. My back wheels are also getting hot but I know the calipers are fine as I've had them apart and greased the sliders so unless the pistons themselves are sticking. My E brake needs attention though as its next to useless and I'm wondering if something may have fallen apart inside the drum and be binding.

 

The E-Brake cable could be sticking so the e-brake is not fully releasing which would cause both sides to heat up.

 

Thanks, its on my to do list but it'll have to wait until after I've moved house next week as my entire garage is packed in boxes. I'm guessing if this has been happeneing for a while then the e brake shoes could well be worn out as it barely holds on a slope. It may well be two unrelated problems with a dying master cylinder causing a squidgy pedal and a knackered e brake. Thankfully in my new house I will finally have a garage to work in so no more lying on the gravel outside for me!

 

More than likely the pistons are hanging up. These things are notorious for that problem. I've tried popping the piston out & cleaning up the seals & the bore, and it still happened. Only solution is new calipers. Crappy design IMHO.