WalterS

On a 2008 Silverado half ton crew cab 5.3l : Have replaced the pads and rotors at 45k miles (12/2011) with GM parts, and again at 56K miles (9/2012) with NAPA parts, due to a shuddering vibration upon applying the brakes. Seems like a persistent problem. Will see if it returns.

Does anybody know how widspread this is amongst the GM line? Is it the pads or rotors causing this? Perhaps the brake pressure is biased too much to the front causing the fronts to overwork and heat up more than they should?

Anybody experience anything similar and have a sure fix? Would aftermarket drilled and slotted rotors help?

grumpychevy

Trucks are very heavy, ceramic pads don't wear very much. Most of the brake dust you see on your wheels aren't from the pads but from the rotors. Rotors wear down becoming thinner heating up faster and warping easier. You should have gotten more than 11,000 miles out of them but the rotors from Napa were probably from China. Next time buy the lifetime warranty rotors and if they warp again you can take them back.

grumpychevy

I re-read it and see that the parts were from gm that you only got 11,000 miles from. You should have gotten more than that so my guess is that they were slightly warped out of the box maybe from storage. Anyway I have bought napa rotors and most are from China. Not saying they are good or bad, just nice to have a lifetime warranty to fall back on. I would guess this is rather common with stock brakes on these big, heavy trucks. Just like most things these days... Nothing seems built to last.

WalterS

The first set were factory. Second set were dealer installed GM, but the rotors were marked BOSCH. They were great for about 9500 miles. The set I just installed myself this week I bought from NAPA. Their 'top of the line, limited lifetime warranty'. Neither the factory set nor the set installed by the dealer were worn out. They just were warped to the point that they vibrated badly. I didn't see the ones the dealer took off, but the ones I took off this week looked fine. I didn't put a run out dial gauge on them so I don't know how much they were warped, but they obviously were. There was not pedal pulsation , so parallelism was probably OK.

I am hoping to have better luck with something other than GM parts.

grumpychevy

I hope these last you a good long time. Good luck with them.

MDTAHOE

Make sure the lug nuts are torqued evenly. Installing with an impact gun without a toque stick is a very common cause.

Mille Racer 69

try these, I love them.
the slotted rtors should be a huge help to keep themselves cool:

https://chevroletforum.com/forum/sil...-rotors-38502/

^link

WalterS

Interestingly enough I asked the service tech at the dealer whether overtightening the lug nuts would cause this. The response was,....the spec is 140 ft lbs, and that overtightening them was an old wives tale.

staggerlee

Strange a service tech would say that.
Wheel lug nuts are an MVSS torque with records kept on each vehicle.

This nuts are put on at the factory all at once.
Its done in 3 torque stages, if one is faster or slower than the others.
They will wait for the others to catch up before the final torque.

Reason I know this, is because I was one of the guys responsible for MVSS torques throughout the plant.
We went through all this trouble to make them go in evenly so it wouldn't warp the rotors.
Once they leave the factory, and an impact wrench is applied, all bets are off.
And you can over torque with just a click wrench.
A click wrench will tell you that torque has been reached, but not if it has been over torqued.
A dial wrench is the correct way.
Lee

WalterS

I have my suspicions that this problem is recurring due to the over or uneven torquing by the guy at the tire shop when I get a rotation and balance. My father in law always without fail, loosens and retorques with a click wrench after anyone uses a air gun on the lugs. We have a state safety inspection here in Virginia and the inspectors are required to remove at least one front and one rear wheel to inspect the brakes every year. He redoes it every time.

Ever go into a tire shop holding a torque wrench? Before you even get to the counter they roll their eyes and say,' OH, here comes one of THOSE guys'.

This time I torqued them to 135 ft/lbs, using a pattern, and first went to 100 then 120, before going to 135 ft/lbs.

Thanks, LEE