How to discern different types of vibration?

[sciphi]

Since this came up in another topic:

Somebody mentioned that a vibration I was feeling in the Buick under high-speed braking might be ball joints or tie rod ends, not brake rotors.

My question is: How can you tell whether a vibration under braking is caused by bad ball joints or tie rod ends, and not by out-of-whack rotors?

 

[The_Jeff]

If your braking force is even and your front end is shot, and the road is smooth and you aren't turning, the loose parts should be locked at one end of their slop.

IOW I don't believe it.

If you had warped/deposited rotors and they pulsed on/off, that could set up a resonance with bad ball joints, amplifying the effect.

You can jack your wheel up and tug on the tire to check all the front end stuff out.

 

[Pete]

Remember, you can help discern front vs rear brake issues by lightly applying the parking brake. And, vibration felt in the steering wheel generally indicates a front-brake problem, while "seat of the pants" vibration, a rear-brake problem.

You might want to browse YouTube to review how to test suspension components...

 

[d00df00d]

Originally Posted By: Pete
Remember, you can help discern front vs rear brake issues by lightly applying the parking brake.

Only in cars where the parking brake engages the normal rear brakes. In some cars (e.g. mine), the parking brake works by an entirely separate mechanism.

 

[AdRock]

True, if you have the type of rear brakes that are disc for the foot brake and drum on the inside of the hat for the parking brake, the emergency brake test method almost never works.