Rooster2 Posted August 15, 2011 Share Posted August 15, 2011 (edited) My 99 OBW right front brake goes thump, thump, thump, when the pedal is lightly applied after driving about 5 minutes. It felt like a slightly warped rotor, so I just replaced that, but it still thumps. There is no pull, and if brake pedal is pressed strongly the thump is gone during braking, and the car comes to a good straight stop. Would this be a caliper issue, or brake pad not sliding properly on the rail, or an issue with the pads? Upon installing the new rotor, I could not see any problem with the caliper, and I made sure to lube the pad slide with anti-sieze. I installed ceramic pads last summer, and have plenty of pad thickness remaining. All bolts, including lug bolts are all tightened up real good. Suggestions welcomed. I took someone's suggestion, and pulled the rotor, and used a wire brush to clean off accumulated rust off the hub. I reassembled, and found I still had the same thump, thump, thump. I did notice that the brake pads sweeping across the facing of the rotor was not consistent. It seemed like the outer half of sweep around the face of the rotor had a brighter metalic sheen look, while the lower inside sweep looked grayer, and duller in color. This presented greater evidence to me, that something was wrong with the caliper. So, I swapped in a rebuilt caliper, and this has solved the problem. Case closed.........no more thump, thump, thump, when the brake pedal is lightly applied, Edited August 21, 2011 by Rooster2 added info Link to comment Share on other sites More sharing options...
89Ru Posted August 16, 2011 Share Posted August 16, 2011 How about the slide pins? Try some caliper grease on them if they are sticking. Are the pads evenly worn or are they angled? If they are angled, try a new caliper and of course new pads. Wirebrush the hub surface that mates to the rotor hat and get the rust out of there. If you have a handheld temp gun try getting the rotor temp when the problem occurs and compare to the left side. My gut says its the caliper sticking and causing the rotor to overheat and warp. Link to comment Share on other sites More sharing options...
Rooster2 Posted August 16, 2011 Author Share Posted August 16, 2011 How about the slide pins? Try some caliper grease on them if they are sticking. Are the pads evenly worn or are they angled? If they are angled, try a new caliper and of course new pads. Wirebrush the hub surface that mates to the rotor hat and get the rust out of there. If you have a handheld temp gun try getting the rotor temp when the problem occurs and compare to the left side. My gut says its the caliper sticking and causing the rotor to overheat and warp. Thanks for the advise. My gut also says it is the caliper just slightly sticking. Both pads seem to have even wear, not angled, and not warn much, so caliper sticking is still prolly minimal. I lubed the slides and pins, so I don't think there is any sticking with them. I just checked, and for less then $50, I can buy a rebuilt caliper from Advance Auto Parts. Good advise too on using a wire brush on the hub to create a tighter fit. I should have done that, when replacing the rotor last week. Thanks again.........Rooster2, (Larry) Link to comment Share on other sites More sharing options...
Mike104 Posted August 16, 2011 Share Posted August 16, 2011 I just did the same thing on the left side of my '99. New caliper, new pads, new rotor. Vibration and noises when applying brakes now gone. Rt side over 80% of pad remaining. I know conventional wisdom is to replace both sides when doing this but I was out of time and low on funds so just did the left side. Link to comment Share on other sites More sharing options...
Rooster2 Posted August 17, 2011 Author Share Posted August 17, 2011 I just did the same thing on the left side of my '99. New caliper, new pads, new rotor. Vibration and noises when applying brakes now gone. Rt side over 80% of pad remaining. I know conventional wisdom is to replace both sides when doing this but I was out of time and low on funds so just did the left side. Thanks for your story......I am going to replace the caliper next on the part replacement installment plan to see if that fixes the problem. Link to comment Share on other sites More sharing options...
CNY_Dave Posted August 17, 2011 Share Posted August 17, 2011 Don't forget that a bunch of rust on the hub-rotor mating surface can make the rotor wobble... and the whole wheel. Dave Link to comment Share on other sites More sharing options...
Rooster2 Posted August 17, 2011 Author Share Posted August 17, 2011 Don't forget that a bunch of rust on the hub-rotor mating surface can make the rotor wobble... and the whole wheel. Dave That is worth looking into. The road wheel does have a little bit of wobble that I noticed when spinning the tire/wheel when up off the ground, but is not noticeable when driving. I did super tighten the lugs for the road wheel, which did remove some of the brake wobble, but not all. Having just swapped out the rotor, it will be ez to take apart, pull the rotor off, wire brush the hub-rotor mating surface, and reassemble. If that doesn't fix it, then I will replace the caliper. Thanks for the advise. Rooster 2 (Larry) Link to comment Share on other sites More sharing options...
89Ru Posted August 17, 2011 Share Posted August 17, 2011 watch the torque on those lugs, 65 ft-lb should be enough and re-tighten after 50 miles. too tight and that can warp a rotor or an alloy wheel Link to comment Share on other sites More sharing options...
Rooster2 Posted August 17, 2011 Author Share Posted August 17, 2011 watch the torque on those lugs, 65 ft-lb should be enough and re-tighten after 50 miles. too tight and that can warp a rotor or an alloy wheel I will remember that. Link to comment Share on other sites More sharing options...
Rooster2 Posted August 21, 2011 Author Share Posted August 21, 2011 I took someone's suggestion, and pulled the rotor, and used a wire brush to clean off accumulated rust off the hub. I reassembled, and found I still had the same thump, thump, thump. I did notice that the brake pads sweeping across the facing of the rotor was not consistent. It seemed like the outer half of sweep around the face of the rotor had a brighter metallic sheen look, while the lower inside sweep looked grayer, and duller in color. This presented greater evidence to me, that something was wrong with the caliper. So, I swapped in a rebuilt caliper, and this has solved the problem. Case closed.........no more thump, thump, thump, when the brake pedal is lightly applied, Link to comment Share on other sites More sharing options...
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