Breaking Issue on my 2004 GMC Sierra Crew Cab

[Heath]

I recently noticed that when I am breaking, especially from a high speed, that i have a shimmy in the truck. The first action I took was replacing the front rotors and pads but still have some shimming taking place but better. Does anyone know if there has been a case where the master cylinder caused this problem? It's sometimes makes it feel like I'm pumping the brakes,  that is why I'm asking. The only other thing i know to do is change the rear brakes and rotors.

thanks

Heath

[Jsdirt]

Probably the rears, especially if disk. Pay attention to your parking brake, too, if it's disk. One of the worst designs in automotive history right there - the disk / hat design. Constant problems. Make sure they're not dragging due to rusted out cables or internal hardware, or jammed up due to delaminated shoe friction material.

 

A master will never cause that kind of problem. Usually when masters fail, they either leak externally or into the brake booster (or both) destroying it, or your pedal will slowly sink to the floor with constant pressure on it.

 

I would also give a good check of your ball joints, inner & outer tie-rod ends, pitman and idler arms. Should be ZERO play in any of that. If you have any howling noises that either amplify or go away when cornering, then its probably time for hub bearing assemblies as well. Make sure your tires don't have any flat spots or bubbles in them, and that the tread is uniform around the circumference. That'll certainly cause a shake!

 

Any kind of play up front can cause shakes or shimmys with very little effort.

[Heath]

Thanks for the quick response! I'll look at rear rotors next!

Heath