by patbruce, October 24, 2015
Just got done replacing the front passenger caliper on a friends '06 I4 auto, brakes are now good but there is a thunking that goes away the moment you touch the brake pedal? What do I need to do when I go back in there? Any ideas on what to look for? Suspension is/was fine, noise started after I put everything back together.....
Pat
Could be any number of things. I'd double check that the bolts holding the caliper to the torque plate (bracket) are torque down correctly. Check that the pad clips have fallen off or were otherwise messed up. Check the torque on the lugs - easy one to miss and can cause this noise.
Could also be a simple case of relubricating the sliding pins (not sure if you had to reuse the old ones or the new caliper came with replacement pins). If the bushing for the pin is messed up, it can cause the caliper to "jump" making a thunking noise right when you touch the brake pedal.
Also a remote chance that there is a suspension related issue - could be CV slop, bad strut, bad wheel bearing, etc. Just happend to be coincidence that it popped up right after you worked on the brakes. Also note that some after market pads can make a lot of noise as well, until they bed in.
But I'd explore all the simple easier stuff first - double check that everything is torqued back up properly and test drive it some more.
Thanks!! I re-used all the old bolts and pins... I'll replace those with the new ones that came with the caliper and see if that fixes it. already checked the torque on the lugs (first thing I checked..)
Is there a rust buildup on the edge of the rotor that can be chipped off with pick hammer, or with hammer and cold chisel? Also make sure the metal shield is not bent in and touching the rotor anywhere.