Braking Shimmy

[JollyRats]

Hey All!

I have a 95 Bronco with stock sized tires and 95,000 miles on it. I have been getting a shimmy while braking recently which is getting worse over time. Uneven surfaces seem to make accentuate it. When it happens I either let off the brakes and ease back into it or jam them hard and the shimmy dampens out.

Any knowledge would be greatly appreciated.

Thanks in advance!

Joe

 

[Justshootme84]

It's possible that one or both of your front rotors are warped. If you can, take off each tire and check the rotors and pads. if the rotor is warped badly, you'll see it's out of round as you look from the top/side and rotate it. JSM84

 

[oktogo]

one of your brake pads also may be stuck and may have warped them

 

[Broncobill78]

What kind of shape is the front end in (tie rod ends, drag link, ball joints, bushings, etc) ? Often a loose front end will become noticeable over uneven surfaces or during braking. Are you feeling this shimmy in the steering wheel or thru the brake pedal ? Although the fact that it seems to diminish under hard braking would point more towards a warped rotor(s) as the others have suggested.

 

[Justshootme84]

ISSUE: The use of air impact tools to tighten wheel lug nuts can lead to overtightened and/or unevenly tightened wheel lug nuts. Air impact tools typically used for wheel lug nut removal and installation can generate up to 475 N-m (350 lb-ft) of torque. Overtightened and/or unevenly torqued wheel lug nuts may cause:

> Brake vibration

> Distortion of the wheel hub

> Distortion of the brake rotor

> Brake rotor runout

> Damage to the wheel

> Damage to the wheel nuts and studs

Very good info, thanks Steve83!!!

The torque spec for Bronco lug nuts is 100 ft-lbs. I don't know how many times I've stopped to help someone change a flat tire, only to find the lugnuts are so tight that they can't be removed with the standard lug wrench or cross. These are likely tightened to well over 200 ft-lbs, and require using a long cheater bar and standing on it to break the lugs loose. If you find that the shop you had work on your vehicle overtightens the lugnuts, find another one. You don't want someone playing NASCAR pitstop with your rig!!!! JSM84