MOBB

Hey guys, I've been having a really bad case of shaking and "thuddering" when coming to a stop at above 50mph it was so bad that my rotors started to develop hot spots on them, I still had about 15% of pad life left. So I said screw it and replaced the front rotors and pads. That has always solved my problems.

So it was a nice day outside today, decided to replace front rotors and pads, Took the rotors off noticed they were really warped after 60k miles. On the drivers side the front side of the rotors where thin and warped, the other side was butter smooth and not a single feeling of warped. The pads had at least 15% life to them. The passenger side rotor had black hotspots on them, the pads were finished on both sides almost metal to metal. So replaced my rotors and pads in front left and right. The calipers were perfect, and lubed everything back up.

The rear rotors where replaced 10 months ago at the dealer along with the pads they look brand new and didnt feel any warping to them.

Thing is when Im driving I still have the same feeling as before I changed the rotors and pads, at 50mph coming to a stop the car shakes and thudders to about 20mph then it feels smooth all the way down. The faster I go the worse the thuddering feels. I do not have a steering wheel shake just a bad vibration throughout the cabin I can feel it as soon as I tough the brakes until about 75%. At 100% braking the car comes to a complete stop smoothly with no vibration I'm stumped!

01tl4tl

you have 15% pads left?- how many MM is that?
When the pads get really low it causes the calipers to extend beyond normal and the wear will be uneven between inner and outer sides
Black hot spots? how do you drive that thing!
Ck your caliper operation and flush the brake fluid to be safe
Its possible there is rust or dirt buildup on the mounting flange for the rotor- clean with 1800 sandpaper, any imbalance will make a vibration

also look inside rotors for contact to steering - shiny metal bits anywhere

01tl4tl

look at your rear rotors on the inner side- is the wear even across the face of the rotor or does it look like only half the width is getting used?

there are some pads for the rear that dont actually fit a TL- even the dealer may get them

I find a proper brake flush fixes many problems LF RF RR LR

MOBB

thanks for the info, will do a brake fluid flush, last one was done about 15k ago at the dealer but will do again. I checked everything and even had a friend look over my job everything looks to be fine. I even brought my car into my mechanic who confirmed everything was fine he suggested doing a through brake system cleaning which I plan on doing along with the flush!

jdjohn84

I would suspect your tires at this point. You may have one (or more) out-of-round. A close visual inspection for uneven wear spots (bald spots) or cupping (you can feel with your hand sometimes) might prove it. Out-of-round tires can feel very similar to warped rotors.

rcb2000

turn the rear rotors that is your problem, waiste of time flushing the fluid, if anything bleed the rear calipers has that is where the problem lies and most likely a warped rotor, so unless your hand has a built in dial indicator your not going to tell if they are warped or not by rubbing your hand across the rotor's surfaces.

fsttyms1

I agree check the rear rotors. They can cause the issue. You may also want to try to bed the pads in and see if that clears it up.

01tl4tl

you can ck runout on rotors by placing a flatblade screwdriver across the caliper and rotate the rotor

you dont bleed just the rears on the TL- ABS plumbing requires driver front then clockwise around the car LF RF RR LR order ONLY

I asked about the wear across inner side of rear rotors because many pad makers are using a backing plate with 3 tabs on the back- the 3rd- middle top tab is not for us (fits rl calipers) and tab hits the piston first, cocks the pad sideways and only half of pad contacts the rotor
Happened on my 01 with hps and rb pads!! have to grind off the middle tab then ok
Caused a freaky shake in the car

Possible the parts dept got or handed out wrong rear pads
Inspect for that visually by the unusual wear on inner side of rear rotors