I have read all of the previous posts on brake shake, I have a good understanding of braking systems and used to repair cars and trucks professionally. My 17 1500 Z71 seems to eat brakes. Rear pad and rotor warpage repeats at 6000 miles. It has 154k miles with mostly dealer maintenance. In the last 12k miles it has had twp sets of rotors (all 4) three pad sets, and all four new calipers. The current sets have 6000 miles on them and violently shakes the truck, feels like rear. The last rotor from the left rear was .075” out of true. It drives straight and extremely smooth till you hit the brakes. Any suggestions?

 

vibration transmitting thru the steering wheel or body of the vehicle?
do you live in the rust belt?
who is servicing the brakes? a gm dealership or independent shop or you?
any smell of overheated brakes?
did the calipers all push back using the proper piston tool? are all the pins moving? were the brackets cleaned and do the clips and pads fit together easily? any irregular wear on the pads?
is the vehicle used for towing and if yes....are the trailer brakes working?

 

Full run down, I am an electrical inspector. Nine months ago I slid off a new driveway into some mud. A rock got wedged between the LR wheel and caliper. When it popped out it broke loose the line at the caliper. I limped it home and made repairs that evening bleeding the system completely. No to long after it developed a brake vibration, it was on its second set of pads but original rotors and calipers. I purchased new “best quality” pads and rotors all around and installed them. These rear pads started vibrating and in less than a thousand miles, at 6k they were wore out. I decided to go whole hog and replaced all four calipers, pads, and rotors thinking the Car Quest “Best” might not have been great. The new parts are Napa Fleet performance. They started vibrating very quickly and now the rear pads are worn out again at 5500 miles. I worked in an auto machine shop before becoming an electrician and clamped steel to the truck with dial indicators. .0005-.0015 run out in the axle flange. Less than .002 on the rotors. Micrometer readings on the rotor thickness at four points around the rotors vary under .002 on all four rotors. I clamped the rear brake hoses and did a test drive. The braking is significantly reduced. Could a bad proportioning valve cause reduced front brake power? Could the trucks reliance on the rear brakes cause the vibration? I am sure the reduced rear pad life is a symptom of reduced front break capacity. Need ideas here.

 

is there even a p valve in the system? there was in the gmt 800's but that was 15 years ago.
the axle flange...your runnout measurement...how did you ensure its not lateral movement of the axle in the diff
Where are you feeling the brake shake...steering wheel or brake pedal?
if you t hink the front aren't working.... do a brake apps then measure all rotor temps with a ir temp gun and post the results

 

Good idea on the IR temp, the shake is not specific to the steering wheel or pedal, more like the whole truck. Worse sitting in the rear seat than front.

 

Might be a good idea to check out the Stability Control system. If it is constantly applying rear brakes when not necessary could be involved.

 

Drive it try not to use the brakes and check brake temp.