New disc brakes...thump thump thump

[GL96]

Well, I just put a set of rotors and pads (front) on Squeezes 99 SEL...everything was fine for a day or so then suddenly....it thumps when braking. Can't really feel anything thru the pedal, the thump slows down as the car slows, no shimmy or shake, just an annoying thump as I brake. Braking distance does not seem affected.

Anyone have an idea?

Thanks in advance.

[downhill]

Originally Posted by GL96

Well, I just put a set of rotors and pads (front) on Squeezes 99 SEL...everything was fine for a day or so then suddenly....it thumps when braking. Can't really feel anything thru the pedal, the thump slows down as the car slows, no shimmy or shake, just an annoying thump as I brake. Braking distance does not seem affected.

Anyone have an idea?

Thanks in advance.

Are you sure the pads are in the caliper correctly. Are the caliper brackets good and tight. Check out before you have to look out~~~!!! I have no clue how good you did the job?? But something is loose and moving. You need to look and find it for safety !!!

[fct]

I replaced my StopTech brake pads with Wagner thermoquet. The rotors are practically new, so I kept them. I also hear clack-clack kind of sound when car is traveling at about 30mph or so. It stops when I apply brakes. My first guess is that my older brake pads were a tiny bit less wide than the new ones and created a tiny lip on the outside diameter of the rotors. Anyways, I am thinking of disassembling and putting everything back together some day to make sure I didn't forget something when changing brake pads. If this doesn't help, I'll have the rotors turned next step.

[radioflyer]

Originally Posted by GL96

Well, I just put a set of rotors and pads (front) on Squeezes 99 SEL...everything was fine for a day or so then suddenly....it thumps when braking. Can't really feel anything thru the pedal, the thump slows down as the car slows, no shimmy or shake, just an annoying thump as I brake. Braking distance does not seem affected.

Anyone have an idea?

Thanks in advance.

I would immediately check that everything has been tightened down to spec. New rotors are known to have become warped just by sitting on uneven shelves or improper storage. That would've been my first thought but you said everything was fine right off the bat. If the rotors you got were indeed warped from the get go then you would've had that symptom from the first test drive. Sounds like to me something has come loose. Did you also replace the hardware such as abutment clips? If you did'nt then you might want to look into getting those replaced.

[GL96]

First off, thanks to all who responded to my post. I appreciate your input.

I took the brakes apart this evening, cleaned all the bolts, mating faces etc. Re-torqued the bracket and caliper bolts to spec, used blue Locktite on the bolts, pads are greased and seated proper, all hardware was new at installation.

The thump (more of a knock than a thump) went away. For a while. Then it went away. Then it came back. Then it went away again. Whiskey Tango Foxtrot.

Would anyone have any other suggestion or is it time to bring it into a shop.

Thanks again.

[behlinla]

You checked/lubed the slides right? You're also sure it's in the front brakes (no noise when using the parking brake)?

It's possible it's just the pads and brakes bedding in. Otherwise it could be a loose suspension component (tie rods, ball joint, bad wheel bearings). You might have also gotten a defective brake rotor that's out of true.

[fct]

Today I took the wheel off to take a look. The lug nuts were pretty lose which is scary. I don't know how this happened. Perhaps I tightened them by hand but forgot to torque them.

[Sardog]

What condition is the rest of the suspension in? Maybe what should be felt as a warped rotor is transferring the energy to a bad ball joint or endlink and causing a thumping sound. Did you clean and lube your caliper pins?


1966 Ford Galaxie 7 Litre, love my 428
1997 Ford F250 CCSB 5" lift and a mean 460
2001 Ford Taurus SEL 3.0 DOHC "wife's car"
2011 Ford Focus SES "my commuter car"

[Tom S]

Originally Posted by radioflyer

I would immediately check that everything has been tightened down to spec. New rotors are known to have become warped just by sitting on uneven shelves or improper storage. That would've been my first thought but you said everything was fine right off the bat. If the rotors you got were indeed warped from the get go then you would've had that symptom from the first test drive. Sounds like to me something has come loose. Did you also replace the hardware such as abutment clips? If you did'nt then you might want to look into getting those replaced.

I am interested in hearing your source on the underlined part. I believe non-true rotors right out of the box but I am not quite seeing that for a cause. I did a little searching online about this and see some info on this but nothing from the right kind of source to convince me.

[Automender12345]

While I was replacing my struts on the front I put a bottle juck under one rotor to lift the knuckle. Stupid!!!!! I got everything back together and I had a thumping on one side, only while braking. After driving it got better and then worst. I finally swaped rotors from side to side and thumping switched sides. I bought a new rotor on the thumping side and all fixed. If the thumping switches on yours when you switch rotors you may ahve a cracked or warped rotor.