Hi, I have a 2006 Hummer H3. The tires and the brakes are all about 18 months old and I believe still in very good condition. I have GoodYear Wrangler SilentArmor tires, and use high quality brakes (I don't use lower end components on my vehicle.)

For a few weeks now, my H3 has been "bouncing" (somewhat forward and backwards - kind of a pumping motion) while braking. It begins at round 25 mph and stops as I get below 10 mph. The pedal does not pump, it's the entire vehicle that goes into this motion. Its somewhat of a gyrating back and forth motion.

I took it to Tire Kingdom and they really didn't seem to know what it might be. They began guessing at different components (i.e. the calipers, the rotors, the emergency braking system...they clearly didn't know).

I'm planning to taking it to the Dealer, but wanted to know if anyone had experienced anything like this on their H3 and what might be the cause.

Your thoughts in trying to figure this out are appreciated.

Thank you,
Fulano

 

My first guess is a warped rotor or a seperated belt in a tire if there are no other symptoms such as grinding, popping or thumping that could indicated a failed suspension part. Good luck and let us know what they find out.

 

Sounds like the rotors. When you had your brakes installed did they turn or replace the rotors? Plus in the last 18 months, I assume you had the tires rotated. If the shop that did the rotation(s) didnt torque the lugs properly, it could warp the rotors in a short period of time

 

I have the same problem with mine 06, thought it was normal since it was like that when I bought it a few weeks ago. I just replaced rear brake pads but it didn't solve anything. I would like to know what's the problem aswell.

 

Another vote for 'warped rotor'.

 

Warped and/or glaze spotted rotors.

 

Rotors do hardly ever warp unless maybe when you get real cheap chinese crap. If you are somewhat handy take the rotors off, get some medium grid sandpaper and hand sand the rotors(both sides). You will sand off the baked on brake dust from the rotor. Clean off with brake cleaner and reinstall and embed the pads again. Costs some time but is free from other cost (ok sandpaper if you have to buy some). I did this once and the difference was amazing. Other thing that could be the problem is your shocks? How many miles on the truck?