Why does left front brake overheat?
The left front brake started overheating, unrelated to actual braking, on my
2006 Malibu Maxx at 115,000 miles, with rotor and pads in good condition.
Found the caliper piston seized, and the forward sliding pin seized/rusted,
which I assumed had caused the caliper problem. Installed
remanufactured caliper, new pads,and remanufactured mounting bracket,
as the seized pin had broken off when I tried to break it loose. Repair
seemed to be a success, but within a couple of days the problem returned.
I have not torn it down yet, but is there any way that the master cylinder
and/or brake lines could prevent the piston from moving back? I wish I had
tried to force the piston back in the failed caliper after I removed the brake
line, but I didn't think of that, and it has been sent back to the
remanufacturer. The brake fluid that drained from the old unit looked
OK/free of water, and the fluid that vented during the bleeding of the new
caliper was in good condition also, suggesting no problem with the fluid
itself. Any comments would be appreciated.
I'd replace the hose first, they tend to wear out internally. See if the condition goes away.
I agree with Tom to check for collapsed hose with rotor seized up loosen bleeder screw on caliper if rotor will spin freely the brake hose is bad if stays seized up caliper piston seized.
Replacement of the flexible line fixed the problem. The old line was indeed blocked in the area where the supporting clamp wraps around the flex line. (I cut the line several places to narrow down the location.) The blockage acts as a "check valve" letting fluid through under pressure from the master cylinder, but letting it flow back only very slowly once the brake pedal is released, thus keeping the brake engaged longer. While trying to recreate the problem prior to changing the hose, I found if I pressed the brakes hard while at a stop on level ground, there was a delay before the car would move forward at idle after releasing the brakes. Also had a bit of an adventure with the new part purchased at O'Reilly Auto Parts, "BrakeBest" brand, PN BH620474, $23.99 +tax. Initially, the new hose leaked at the caliper/hose joint. Inspection of the new copper washers provided with hose showed that the outer washer had embedded onto the hose mating surface thoroughly, as evidenced by clear concentric ring markings on the surface of the washer. The inner washer (between hose and caliper) showed little evidence of being deformed, despite having the identical clamping pressure applied to it. This suggests the inner washer was too hard, not properly annealed. A comparison of the new washers to the old (still embedded on the old hose) showed that the new ones are larger in OD (0.637" vs. 0.590") with about 1/3 more surface area, making them that much more difficult to "crush." I took one of the old washers and used it (smoother side toward the new line surface) and the leak was fixed.
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