Rear Brakes "Dragging"

[A1cntrler]

I replaced the rear brakes about 3 weeks ago (07 ST Limited, 4.6 4x4). New Raybestos Rotors and Raybestos pads. When I pressed the piston in, put the new pads on and tried to fit the caliper, the pads or the rotor were slightly too thick for me to rotate the caliper into position. I had to press the piston in further (slightly) to get it to swing down. For about two days (short trips of 3 miles or so only) the rear brakes felt like they were dragging. To maintain speed of 30mph required about 2k RPM, and if I let off the gas, it didn't coast and would nearly drag itself to a stop.. I figured they were just tight tolerances and it would clearance itself as I drove. After a couple days it seemed to coast normally again.



I have only driven the ST maybe 200 miles now (again all short 3 miles or so round trips). Today I drove out further on the highway (about 10 miles) and when I got to my destination I could smell the brakes as soon as I got out. Reaching down and placing my hand about 6" from the rear wheels I could feel the heat coming off, and could see the caliper grease I had on the back of the pads steaming/smoking. What could the issue be? I have done many, many brake jobs before and only had this issue on my '95 Grand Prix, but they had funky rear calipers that had to be threaded back into position and would freeze up frequently requiring replacement.



The pads/rotors were the same visually as the ones I took off with the exception of an Anti-Rattle clip on the outer pads. It is just that the manufacturer made things a little thicker then they should have been?



The link will take you to the post I made earlier showing what parts I used.

 

[Todd Z]

Something is not right, were the calipers turned back properly? did you bleed the system? did you lubricate the slide pins in the calipers....



Something is hanging up, the caliper should drop on the new rotor, if you had to push the caliper back more it sounds like it was not properly turned back all the way...



Todd Z

 

[Richard L]

I suspect that the calipers have corrosion inside and the piston is sticking. Dragging breaks often show up after replacing pads because when the piston is pushed back into the caliper, it is now dragging on the corroded area of the piston bore and that causes it to stick and not retract when you release the brakes. It will wear your pads out very quickly and can cause other damage due to the overheating.



Replace the calipers! You do not need to buy expensive new calipers from Ford, you can buy Rebuilt units from you local auto parts store like AutoZone, etc. The often offer rebuilt calipers for $20 to $50 each depending upon the vehicle model, and the also offer 50K mile to lifetime warranties.



Then you need to make sure you flush your brake fluid when you complete your caliper swap and do a brake fluid flush with every brake job or 2-3 years. If your rear calipers are corroded, I would bet your front calipers are getting that way too.



...Rich

 

[A1cntrler]

Yeah, I was kind of afraid that replacing the rear Calipers was the ticket. After looking them up they really aren't as expensive as I though they would have been.



However... I had some time to kill so I pulled them back down and lubed everything up again and reseated the piston. Drove it 30 miles and the rear brakes behaved normally and did not generate absurd amounts of heat. They were about as warm as the front brakes. I only live about 1/2 miles from the exit off the highway, so that was after a 75mph to stop at the end of the ramp. I will keep my eye on them here for a while, and if the problem resurfaces I'll get the calipers and install them.



Todd, when you say "turned back" I think of my '95 Grand Prix where the rear pistons had to physically be threaded back in because the parking brake was also the disc. It didn't have a separate drum park brake. I checked on here before I started the job and found out that on the Gen2 Tracs the piston is pressed straight in like the fronts. My Gen1 had rear drums on it, and never had to mess with them the entire time I owned it. I have no idea how the newer Gen1 Tracs with rear discs operated though.



Thanks for the responses.

 

[Richard L]

A1cntrler,

Yes, rebuilt calipers are not that expensive and well worth the money to get a good brake job...if you are doing it yourself.



I suspect that you probably have a bit of corrosion that build up behind the pistons over the years and why you pushed the pistons back the pistons are now positioned over the corroded area which can make them stick. I always get rebuilt calipers with every brake job.



Your corrosion may have been minor and re-seating the pistons again may have temporarily broke the pistons loose, but I doubt that it was a permanent fix.



Keep your eye on it because the extra heat created by the brake dragging can really mess up other brake parts and makes the repais even more expensive, not to mention the possible loss of control under hard braking.



...Rich

 

[EddieS'04]

I suspect that you probably have a bit of corrosion that build up behind the pistons

This is why I keep clean brake fluid. And when I do pads. I take the bleeder out.

No C clamp. If I cant push the pistons to the bottom smoothly, with my thumbs. I pull them apart. if it is minor cleaning. and new o-ring and dust boot. I repair it. If it is cruded with rust and gunk. I do as Richard does. New rebuilts.

 

[Richard L]

Eddie,

I inspect my calipers the same way. I open or remove the bleed screw and push the pistons in only with my fingers...That lets me feel any binding of the piston that would indicate corrosion in the piston bore. I also flush the brake fluid with every brake job or every 2-3 years, whichever comes first. I have found that the dryer air in Central Texas allows me to extend the fluid flush to 3 years.



I have done that for many years, but now I just get rebuilt calipers with every brake job. I found that rebuild kits cost almost as much as rebuilt units which often come with lifetime guarantees. Once I buy the first set of rebuilt calipers I just take them back to the Auto parts store and get a new set when I do the next brake job.



...Rich

 

[EddieS'04]

Rich,,

I guess Im like you. Keep it clean. It has been many years since I have rebuilt, or had to buy a replacment caliper.