brake help

[importcrazy]

need some help....when i apply the brake and slow down i hear a thumping noise and i can feel it on the pedal, and the brake warning light comes on sometimes, and goes off other times, any idea what this thumping noise would be? thanks!

 

[Black95TSIawd]

try bleeding the system or check your master cylinder.

 

[Defiant]

The thumping could be a warped rotor or loose wheel, and the light is flashing because your brake fluid level is low.

 

[Turbo Guru]

Check to make sure that all of the calipers are tightly bolted in place. I had a customer recently ('94 Mitsubishi Eclipse N/A) whose rear caliper upper slide pin on the left side had backed out allowing the caliper to move outward to the wheel when the brakes were applied. His stated complaint was that there was a thumping noise and his pedal would sometimes go to the floor (and brake light would come on.) after removing the caliper and extracting the dislodged slide pin from the cradle it was rebolted to the caliper and reassembled with new pads and a freshly machined rotor. The brake problem was cured. On a side note the slide pin has a hex bolt head on the side that is inside the cradle orifice in case you were wondering how to tighten it. Also the fluid level will drop in the master cylinder resevoir as more fluid than required normally is pumped to that wheel when it's caliper piston is over extending due to its exagerated ability to move, this will trigger the brake light to come on. When the brake pedal is released the fluid level in the master cylinder resevoir will appear normal because the caliper retracting will push the fluid back into the resevoir.

Hope this helps,
Joe