Haven’t seen this exact symtom anywhere. So the brakes are smooth as silk until AFTER I have been driving at high speed for a while. Then they shudder like crazy. Seems like if it were a warped caliper it would always be warped. Can a rotor warp when hot and then return to normal? The rotors have been replaced and made no difference. I was thinking a sticky caliper? No noticeable drag on front wheels when jacked up immediately after driving. I do get steering wheel shudder at same time so don’t believe it can be from the rear drums. Before I spend a lot on new calipers and rotoers, could this be an anti-lock problem? Seems like the anti-lock wouldn’t cause steering wheel shedder as both brakes would be intermittantly applied together. Anyone had similar problem and solved it?
check if bearings are worn ?
at high speed they would heat up and it might change the behavior?
AFAIK repair manual on the car would tell the maximum “play” allowed in bearings, so should be not that hard to check.
After driving enough to start shudder, stop and carefully feel the rims.
Are one or more hot?
Dragging brake could be releasing before you get it jacked up.
Good ideas above. It could be an ABS problem too. That’s often described as a shaking sensation and could be felt in the steering wheel I’d guess. I have no theory why the ABS would kick on only after driving some time though.
Could be caliper also.
My 05 4-runner had a design problem with the front calipers. I replaced them at least 6 times.
What happens is one of the 4 pistons gets stuck and when you brake it causes uneven braking - which feels like the rotor is warped.
May not be a brake problem at all- might be something in the front suspension giving up. The tension of it getting up to, and maintaining speed may shift something a little extra out of spec, and then you feel it when you start slowing back down.
Considering how important the brakes are to the function of your vehicle, it’s something you want to get to the bottom of quickly. There have already been some great suggestions. Here is an article that offers some other suggestions that could be causing the problem. Hope it helps.
I’ve had that issue with a rear drum brake sticking.
Thanks for all the input. I had thought of wheel bearings - I know Click and Clack often mention them when a caller reports shudder etc. Certainly ought to be replaced with 190K mi anyway. No one wants a seized wheel bearing at speed!
Replaced wheel bearings. Pretty cheap but had to have a shop do them not having the right press. Went ahead and got new rotors and the shop suggested having them turned even though new. Sounded like a good idea and no charge. Made sure the calipers were clean, well lubed and not sticking,
So far so good. Brakes as smooth as silk - just hope it lasts.
Thanks again for all the input.
unfortunately, you don’t know if the problem was brakes or wheel bearings…