This is a friends 97 4-cylinder accord SE 250,xxx miles, fully oem

The brake pads are dragging on the (front) rotors to the point that it makes this weird smell and the brakes caught on fire. Quickly extinguished the brakes and nothing was damaged. Replaced the master cylinder, pads, calipers, bleed all brakes and took the car for a ride. Before I left the temps on the wheels were 76 degrees. Brake pedal doesn't sink to the floor and doesn't feel spongy. Started smelling that burning smell again so I parked it (fire extinguisher in the back seat just in case). Took the wheel off and tried to get the bore back into the caliper, and it was tough. Never seen them this tough.

Used a temp gun and the temps were as follows:

Rotor 225
Pads 170
Calipers 150
Rim 130

What I am thinking is that the brake fluid is not making it's way back to the master cylinder, therefore leaving the caliper bore pressing the pads.

Could this be an issue with the proportional valve? Any help is appreciated.

 

If the brakes caught on fire, what about damaged rubber hoses to the calipers? Seems like they would be more likely damaged by the heat than the proportioning valve.

If you really seared the brake-pad material into the rotor surface, and didn't replace the rotors, some of that smell might just be left-over. Temperatures you list don't seem outrageously high. Think maybe the original problem might be sticking caliper-slide-pins but now those are new.

 

The hoses to the calipers were untouched by the blaze. As soon as the fire started, I extinguished it. The smell was there before the fire also. The slid pins have been replaced and properly lubed. Also the holes they mount into the caliber brackets have been cleaned out.

 

A caliper that has rust in the cylinder (dust shield missing or damaged) will not relax and unload the brake pad. Result is very hot rotors and lot's of brake pad drag. When brake pressure is absent, you should be able to turn the wheel by hand w/ modest effort. There is some pad drag but not binding.

good luck

 

Thanks. The calipers were replaced so there shouldn't be any rust in the cylinder.

 

This is a common problem on older cars. It happened last year on my 74 corvette. The rubber brake line to the calipers collapse internally and will not let the brake to release the pressure after the brake is applied. replace the 4 rubber brake lines

 

Coincidence you said that because the front brake hoses have been replaced prior to me working on the car.

 

You didn't mention that they were replaced. Were they replaced before or after the brake fire?

 

Sorry I didn't mentioned that before, but they were replaced prior to me working on the car. Like years ago.

 

I would check them carefully before ruling them out as a cause for the problem.