brake problem

[bsbladine]

Hey, I'm new here but completely out of ideas on this problem. I have a 99 tahoe 4 wheel with brake problems. When I hit the brakes they shake like mad but it is only after a long drive or when I am at high speeds or towing my boat. I can run around town with little or no problems. I have replaced the pads and rotors and that did nothing. Any other ideas?

 

[ravingmadman]

Drums/rotors? Wheel bearings? Ball joints? Could even be steering. Describe the shaking- is it side to side, or wheel hop, or studdering?

 

[bsbladine]

It is a side to side shake. The ball joints were just replaced about 20,000 miles ago and the wheel bearings seem to be ok.

 

[ravingmadman]

Hm. How are your shocks?

 

[bsbladine]

Shocks seem fine also. Afriend thought maybe it was a leak in the vacuum hose to the master?

 

[ravingmadman]

Can you feel the shake in the pedal, the wheel, or neither? I'm still getting some background. I'll spit out a prognosis in a minute....

 

[bsbladine]

I feel the shake in the wheel. Not in the pedal

 

[ravingmadman]

Ok. I bet you'll find a good amount of play in your pitman arm, and idler arm. Jack one front wheel off the ground, push/pull left and right on the jacked up wheel. It shouldn't move. Push/pull top to bottom, it shouldn't move. Left-right movement is pitman arm/idler arm, top-bottom is wheel bearings, since you've done the ball joints. If you aren't feeling anything in the pedal, you've replaced the pads/shoes- I'm skeptical of the brakes being the culprit. There are many other forces exerted on the rig while decelerating, and a wobble like that after replacing the brakes smells like steering or suspension to me. Give it a go- I might be way off, but that would be my next thing to check. I have a write up on how to swap out your pitman arm. It isn't expensive (~$50?) or difficult.

 

[bsbladine]

So if I find side to side movement when I jack up the wheel, I should replacement the pitman arm and idler? Or just the pitman?

 

[ravingmadman]

So if I find side to side movement when I jack up the wheel, I should replacement the pitman arm and idler? Or just the pitman?

You'll want to do both, because if one is worn, the other is probably just as bad. The pitman arm is like $50, and the idler arm is something like $30. it will take you an hour or two to do.

Here's a guide for the pitman arm- the idler arm is super easy.
http://www.tahoeyukonforum.com/forum/showthread.php?t=2052&highlight=pitman+arm