This problem has me quite perplexed. Last June, I installed rear PBRs on my 91' drum car using Ed's backing plates. I sourced EVERYTHING new from the dealer except the calipers, which I got from a 95' Z28. I rebuilt both calipers using the PBR rebuild kit, also sourced from the dealer.

My problem is this: For the first 4,000 miles of operation, they worked perfectly. After a particularly long trip, I noticed that my brake pedal would have extra resistance at about 40% of the travel; when I gave it a little more pressure, it "let go" and finished it's travel. With this staccato brake pedal, I also hear a pop/squeak from the rear of the car.

I checked the rear calipers and I found that they aren't floating properly, they are dragging on themselves somehow. I checked the pins, they were still well greased. All the components were properly aligned. I found that when I loosened one of the pin bolts, the caliper would float without resistance.

Remember,all the parts are new and the pins are very well greased. I'm at a loss to explain this problem, and it is severely limiting my brake performance.

I'm going crazy trying to figure this out!!

I

 

Sure sounds like one of the pins is bent. One of them goes through the e-brake bracket. Is the bracket flat against the caliper?

 

Bumping my own thread. Problem still persists! Today I put the car on jack stands, and tested the parking brake. The parking brake will only hold one wheel while in idle, and free travel adjustment on the caliper that isin't holding hasn't fixed it.

The free travel adjustment either locks it up or doesn't, regardless of the parking brake being engaged. Also, while in the air, depressing the brake pedal will BARELY slow the rear tires down from 30mph. You really have to mash it to get it to stop. Any ideas guys? I'm this close to tossing these brakes and moving over to LS1 rears.

Just before anyone asks, it also has a new disc/drum MC, and a 91 disk/disk prop valve.

 

A bad flex line can act like a check valve and hold pressure. I still sounds like a bent pin. Can you still loosen one and get the caliper to float freely?

 

Yes, when I loosen one it will float freely. I don't understand why they'd be bent, they are new delco pins. Also, the bracket is flush to the caliper. I also replaced all the flex lines when I did this job. All parts are new.

 

bump

 

You're first post describes a failure on a trip at about 4K when this problem started. Don't know what happened but something did. Backing plate shifted or bent, abutment bracket bent, the pins bent. Both sides are binding? Is the rotor still centered in the abutment bracket on both sides?

I have an extra new abutment bracket I could loan you if you promise to send it back. Pins and adapter bracket I can't help you with.

 

I'm going to be pulling it all apart this week, I'll let you know if I need to borrow it. Thanks for the offer, by the way!