2000 Gmc 2500hd - Brake Issue

Lobell · August 7, 2008

Hi all, just got a 2000 GMC 2500. Great truck and havnt had any issues with it, but I just went to get an inspection done here in New Jersey and they said that my brake pedal went down to far, "insufficient pedal reserve" is the term they used.

I never noticed a problem while driving the truck but here is what I have found out since they told me about it. When the truck is off and you press on the brake pedal it stops about halfway down and you can't press it anymore. When the truck is started up and in park, you press the brake and it goes half way down without a problem then gets a little harder to press but keeps going. After you pass the 1/2 way mark though you can hear what sounds like air comming from the footwell or infront of the firewall. After 3/4 the noise gets louder untill the brake is completly to the floor.

When you are driving on the road the brake are very responsive. If you press them the brakes hard about 1/2 way down the tires will lock so the brakes seem to be at least working. I didnt even notice any issues as the truck drive and stops fine.

Any and all help would be greatly appreachiated. Also to note, we have a Brake-Force brake controler on the truck for towning an inclosed car trailor. I dont think this would cause the problem but maybe? Brake-Force Link

Thanks again, please feel free to email me at [email protected] as well!!

-Brian-

PS - I just went out and did a quick test with someone else pressing the brake while I listened in the engine bay. I took a picture of the hose that the noise was coming out (the hose vibrated with pedal pressed). It seems to be going to the engine/power steering pump? When the pedal is pressed down all the way it makes a sucking noise and then when released its fine.

bossier62guy · August 7, 2008

You've got hydraulic assist brakes on your truck thus the reason for the hose running from the master cylinder to the power steering pump. Stupid question but I'll ask it anyway....have you checked the rotors, pads, etc. for serviceability? I also don't think you should be able to lock up your brakes if the antilock system is working fine.