Highway Speed Shake When Braking (1 Viewer)

[LFD2037]

I started a thread a few days ago similar to this but since so much has changed w/the situtation I thought it best to start a new thread.

Scenario:
When coming off the highway & I use moderate to extreme braking I get a shake/shimmy/vibration. I feel it a bit in the steering wheel but mostly thru the seat & can see the dash kinda bouncing up & down. The harder I press the brakes the worse it gets. Doesn't do it @ all under 30 MPH, doesn't shake/vibrate @ all unless I apply the brakes & I feel no pulsing thru the brake pedal. I've checked:
rotors
pads
wheel bearings
rotor to hub bolts
lug nuts
had tires balanced & rotated
looked for anything obviously loose
removed ABS fuse

All of those items checked out normal & made no difference in adjusting. I thought it was a warped rotor problem but it doesn't do it under 30MPH & I feel no response of it in the pedal. What the heck could this be?

 

[baggar11]

Rebuild the calipers...

 

[ChiTown]

Or warped rotors.

 

[Kuneefay]

Probably warped rotors. Just because you dont feel it at 30mph doesnt mean that its not a rotor. The higher speed will accentuate the issue. Replace with oem, stoptech, ebc something quality. I've had great performance out of stoptechs slotted rotors.

 

[baggar11]

I replaced 2 sets of rotors with stock and brembo's. Still had shaking. I'm not saying rotors aren't the issue 100%. $10 for a caliper rebuild kit is easy and cost effective. Plus, OP listed that he's checked the rotors.

 

[Kuneefay]

He didnt say how he checked rotors and i do agree that if he is already there he should rebuild or replace the calipers. Probably check lines for damage too. If a caliper is sticking it could have caused the rotor to overheat past specs and warp.

 

[LFD2037]

All the rotors and pads have less than 10K miles on them. Is it possible to have them mic'd or 'turned' while still on the vehicle? It's rather labor intensive to get the front ones off.

 

[baggar11]

Yeah, you can get them turned while on the vehicle. Last time I checked on that, it was much more costly.

Rebuild the calipers first and see if that makes a difference.

 

[ChiTown]

Turning them on the vehicle is the only way Toyota allows it any more. It's usually cheaper than taking them off to turn them and takes into about hub runout which of the car machining doesn't.

 

[baggar11]

Turning them on the vehicle is the only way Toyota allows it any more. It's usually cheaper than taking them off to turn them and takes into about hub runout which of the car machining doesn't.

Serious? How much does it cost you to get your rotors turned at a shop? Costs me $16 per rotor here. Only shop I could find that would turn "just my fronts" while on the vehicle wanted $200. My local Toyota dealership didn't even have a lathe for on-car brake turning.

 

[JLee]

Serious? How much does it cost you to get your rotors turned at a shop? Costs me $16 per rotor here. Only shop I could find that would turn "just my fronts" while on the vehicle wanted $200. My local Toyota dealership didn't even have a lathe for on-car brake turning.

I imagine a front rotor R&R at a dealership is going to cost you more than $168 in labor.

 

[OGBeno]

Turning them on the vehicle is the only way Toyota allows it any more. It's usually cheaper than taking them off to turn them and takes into about hub runout which of the car machining doesn't.

Incorrect. Toyota does not force any one to do it on the vehicle. They recommend it, but not force it. We still use a brake lathe.

 

[Onefastrx7turbo]

Shaking at speed could be tires/wheel balance, bearings or rotors.... rebuilding the calipers will likely not remedy your issue.

 

[LFD2037]

Shaking at speed could be tires/wheel balance, bearings or rotors.... rebuilding the calipers will likely not remedy your issue.

Shaking @ speed ONLY when brakes are applied. Tires/wheels have been just balanced & rotated (made no difference), Bearing preload was checked (was good), rotors/pads have less than 10K on them. How quickly can rotors get warped?

 

[Kuneefay]

They can warp immediately if the calipers are having a hard time releasing. Also wear can be accelerated by improprer break in

 

[BILT4ME]

Also, if the rotors were installed and not torqued with a torque wrench, they can be warped by the guy running the impact wrench or other. Make sure the rotors are TORQUED properly to the hub. Too late for this set though.....

Otherwise, have them turned on the truck. If you know anyone in a Semi-Truck shop, they may also have the capability to turn the rotors on the truck.

 

[Onefastrx7turbo]

Well, the "warped" rotors is more of a misnomer than fact. While it is possible for a rotor to have excessive run-out from being overheated, the "pulsing and vibration/shimmy" you're experiencing is likely from brake pad material building up on the rotor surface. This material is transferred from the pad to the rotor by baking the pad onto the rotor surface. This is done after hard braking and holding the brakes at a stop light. The pad leaves material on the rotor in that spot and so the next time the brakes are applied, the braking coefficient of the pad material on the rotor is much higher than that of the rest of the rotor surface thus causing the "pulsing" or shimmying at high speed.

Here is the article speaking to this.

http://www.stoptech.com/technical-support/technical-white-papers/-warped-brake-disc-and-other-myths

 

[bsmart82]

^^^ This right here. Excessive thickness variation is usually where brake pulsation comes from. This can be from overheating your brakes, or even low quality pads. I have also seen poor rotor finish after a resurface cause excessive pads transfer and cause a pulsation.

 

[fj80pb]

Too many variables could explain this IMO. Before jumping to any conclusion, I suggest further reading

http://www.stoptech.com/technical-support/technical-white-papers/-warped-brake-disc-and-other-myths

I sure trust the knowledge of these guys
Hope this helps
Cheers

 

[fj80pb]

Ooops. @Onefasttrx7turbo is fast indeed!!!! (faster than me for sure)