I have a wierd brake issue, which I've had the local dealership look at... Ofcourse they couldn't find a problem.
When I'm slowly braking the pedal all of a sudden presses in about 1/2 inch and it almost locks up the truck. I can slowly let off the pedal but it continues to stop very aggressively. If I quickly let all the way off and reply the brake its fine. Here is the kicker, it only seems to do it on gravel when I'm going downhill. I've only had it happen once on pavement when I hit a bump while stopping. I have made sure it wasn't my foot just moving because of vibrations, the same thing happens when anyone else drives. Its done it since I bought the truck new. I'm just afraid someday something bad is going to happen.

Any ideas?

 

I wonder if maybe the brake assist is kicking in prematurely. Brake assist is supposed to automatically apply much higher brake pressure if a panic stop is detected.

 

It sounds like a sensor for the ABS, DAC or anti-rollback may be malfunctioning. Does the car beep or flash any indicator lights when this happens?

 

There are several systems working separately and depending on road conditions working together. Sometimes when braking and hitting certain types of bumps/road conditions these systems trigger each other. From what you describe (On the gravel) it sounds like the electronic brake-force distribution (EBD), brake assist (BA) and anti-lock braking were all working together. When you hit the pothole on pavement, while (hard?) braking, it was probably again a combination of these nannies fighting each other. It is not uncommon under these unique conditions to trigger these odd results. There is also vehicle stability control (VSC) and traction control (TC) tied into this system. You should also get some combination of beeping and idiot lights flashing. Believe me; these little quirks are worth having these systems in place. In time you will be VERY glad they are there, especially under emergency situations. The downhill assist can ONLY be engaged in 4Low and hitting the button. Hill start assist will pulse the brakes every time the vehicle starts to roll backwards. It will NOT completely lock the brakes so you will not slide on ice or snow. Again sometimes it may seem like something is wrong but it's just the complexity of these systems and them sometimes fighting each other.

Koz

 

Well this will atleast supply you with a good laugh. With almost 50k on the stock wheels, I wasn't looking forward to that lovely 265x65x17 times 4 tire bill. So I replaced my tires with Bridgestone Revo's, all I have to say is WoW what a difference. Anyways, with the new tires I went to test my problem, guess what, its not there anymore. So I guess the what happened was the lack of tread was causing me to skid while stopping which caused all the braking systems to hate me. Not sure why I didn't think of that before, since I've always hated them stock tires.

Oh well, thanks for all the imputs though!

 

Thanks for coming back and updating us.

I guess it's good to know that the system works as advertised. It detects the skid WAY before you can feel it.