Manager Forum

I got this 2006 Chevy Suburban K1500 with a 5.3L engine with only 69,848 miles on it. It has a serious brake issue in that it eats rear brake pads in under 6,000 miles. We installed a Wagner Pad Set #QC975B which is a ceramic set. I checked the system and nothing is obviously wrong. I also installed brake pressure gauges on both front and rear calipers. The front shows 1,300 lb pressure and the rear shows 600 lb pressure with the engine running. My question is are these pressures close to correct or not? Does anyone know?

Are the rear brakes dragging. Id try to make sure the rear calipers are not hanging up. If they drag id be looking at the brake master cylinder or a booster issue

brianp87 wrote:Are the rear brakes dragging. Id try to make sure the rear calipers are not hanging up. If they drag id be looking at the brake master cylinder or a booster issue

No dragging at all. As soon as the pressure gauge is at zero the rotor is free and can be rotated by hand with minimal effort.

How long does it take for the pressure to go to zero?

Without looking it up the balance between the front and rear sounds good. The first thing I would look at is the abs module and look closely to see if any brake lines have been replaced including any splices. There are applications that have a weight sensor tied into the rear brakes that adjust the pressure to the rear brakes. It really sounds like an issue with the abs module. I'll run this through all my assistance programs and see if I get a reply. Does this vehicle tow a trailer on a regular basis?

I have also thought of the ABS module as a possibility and I am wondering how to determine that or what to do to test it?

I would look closely at the lines first. The pressure return speed mentioned above is a good point. If you have a kinked, restricted, or mickey mouse repaired line that is crushed in a union you would in fact get pressure quick enough but the release will be definitely slow causing a drag. Another tell will be the color of the rear rotors. If they're blued badly I would key in on a return issue in either a line or caliper slides. If all is fine I would replace the module just on the fact of elimination. Sometimes we have to resole an issue by eliminating all else. Good luck

I understand all being said steve. The rotors indicate no dragging. They are the color of normal brake rotors that are being used. Regarding the speed of rear brake pressure release, as soon as the brake pedal is released, even with the engine running, the pressure gauge drops to zero instantly and the rotor is free to turn, indicating in my mind that there is no reason to suspect a line issue or a caliper issue on either side. Might we just have a bad set of pads? Regarding module replacement - cost may be a factor simply to experiment.

fyi The cost of the module and valve assembly from the dealer cost me $980.36.

So heave a set of oem pads in from the dealer. Pads could be hanging on the slide or something along those lines. Keep an eye on the wear and I would also spend some time with the customer asking if anything was done to the truck within the last 6 months and especially if the person you're dealing with is the primary driver, if someone else had the truck for a period or time within the last 6 months to a year where a repair may have been done. What the truck is used for. Are they the original owner and if not when did they purchase it. Were the rear rotors recently replaced somewhere else because of a pulsation. Has the ABS light been coming on anytime in the past 6 months and was it repaired somewhere else. I really get into my Dick Tracey mode in situations like this one. Any information that can be dug out may be the key to the answer. I had an issue where a good customer had work done at another local shop because I was to busy to do it right away and his neighbor swore up and down that his mechanic was the best in the world and also the cheapest. My customer didn't want me to know he "cheated" on me so it was kept a secret until I asked about some new work I had no record on. It was the key because the master tech had reversed more than a few evap hoses.

The other issue here is you have to make it clear that you aren't assuming you screwed up and aren't going to own brake issues on this truck for it's life. If this isn't handled correctly the brakes haven't been right since you screwed them up. I would also look for any updates on the whole brake system. Answer may be found there. Sometimes dealers don't know about any tsb's about part updates. I just ran across this with a Dodge Challenger. It had a reman rack installed at Pep Boy's and it started blowing off pressure lines. The rack and lines have been updated. The racks had all been reworked from Dodge so there wasn't an issue but the old lines were still being sold. I'm a bit shocked that I knew more than the dealer but I'm seeing it more and more. Sorry for the babble but as we all know sometimes when I get going I tend to cover more than one issue on more than one point.

From experience I know the rears wear faster then the fronts on these vehicles (my wife has a 2004). That being said 6 k is way to soon no matter how a person drives. I do not use wagner pads I tried them once and they made noise so I quit. I would try another set of pads and go from there. If the pressures release instantly for you and you cannot duplicate any dragging issues what else can you do.

Have u tested hot or cold or both. I would test both it could hang up hot and not cold. Make sure the pads can move easy in the mount with Ur hands. I know it might sound weird but had a truck that was kind of doing the same thing. When i was checking it out found the fluid in the bake was green. Changed out the fluid and then never did it again. After i was done did some checking and found that the fluid changes color in them from all the brass. All i know is that after i was done it worked great...

92zman wrote:Have u tested hot or cold or both. I would test both it could hang up hot and not cold. Make sure the pads can move easy in the mount with Ur hands. I know it might sound weird but had a truck that was kind of doing the same thing. When i was checking it out found the fluid in the bake was green. Changed out the fluid and then never did it again. After i was done did some checking and found that the fluid changes color in them from all the brass. All i know is that after i was done it worked great...

That's why we test the brake fluid for mineral content at the service intervals then flush it as needed.

A lot of great points being made here and I'm not in the mood to look at each one and think about it. I've run into issues that the manufacturer will fall upon an issue and instead of posting a recall or tsb on it they keep it their dirty little secret. This may be one of these times. If you are at all friendly with the parts manager at the local dealer maybe you could talk to him. For all we know there may be an updated pad that resolves this issue and none of the aftermarket manufacturers have done anything yet.