Excessive Brake Pedal Travel '95 C1500

bugman74 · February 13, 2009

Hi Guys,

I've had a problem with brake pedal travel for a while on my '95 sierra (C1500 reg cab, long bed). This truck has the vacuum brake booster and the standard 10" dia x 2.25" wide rear shoes. So I decided to rebuild the system, but I still have problems. Following the GM service manual, with the ignition off after pumping the pedal I still have over 4" of pedal travel with ~100lb on the pedal.

Here's what I've done so far:

Rear: New shoes, new hardware kit, rebuilt brake cylinders, resurfaced drums.

Front: New pads, new hardware kit, rebuilt calipers, resurfaced rotors (new oil seals/repacked and adjusted wheel bearings)

I have replaced all 3 rubber brake lines with the Russel stainless steel lines.

I also rebuilt the master cylinder.

I have bled the daylights out of the system, and there is nothing but new brake fluid in it. I still have 4"+ of pedal travel. The brakes work fine, and dont take an excessive amount of force to stop the truck.

The only things left that I can think of that might cause this is:

1) Air in the ABS controller/modulator (I dont have a Tech 1 to cycle the ABS, but I assume I could "drive" it on jackstands to actuate the ABS then bleed the brakes again.)

2) Bad "quick take up valve" in the master cylinder (rebuild kits dont come with new ones)

3) Bad vacuum booster?

4) Brake pedal pushrod too short?

Any thoughts on what it might be? Is there something I am overlooking?

Thanks!

kuhl_530 · February 14, 2009

I have a similar problem with my 95 k1500. My brakes seem to "wander" from 2" of travel up to 4" for no reason at all. Like you said, the truck stops just fine, but it's still unusual enough to raise a flag. I may have air in the lines to the rear brake, or it is possible we both have bad boosters.

bugman74 · February 17, 2009

I have a similar problem with my 95 k1500. My brakes seem to "wander" from 2" of travel up to 4" for no reason at all. Like you said, the truck stops just fine, but it's still unusual enough to raise a flag. I may have air in the lines to the rear brake, or it is possible we both have bad boosters.

Is there any way to test the booster?

bugman74 · February 27, 2009

FYI: I solved my problem. I think it WAS air in the ABS system. I took it out today and found a nearby empty road and cycled the ABS a few times. I came back and bled the system a few more times. It made a HUGE difference!

ALange · February 28, 2009

FYI: I solved my problem. I think it WAS air in the ABS system. I took it out today and found a nearby empty road and cycled the ABS a few times. I came back and bled the system a few more times. It made a HUGE difference!

If that wasn't a fix I would double check the rear brake adjustments. I adjust the brakes out until I hear them rub when spinning the wheel, pump the brakes, and adjust it again until I hear/feel it touch slightly. Excessive brake shoe travel will translate to excessive brake pedal travel.

bugman74 · March 1, 2009

FYI: I solved my problem. I think it WAS air in the ABS system. I took it out today and found a nearby empty road and cycled the ABS a few times. I came back and bled the system a few more times. It made a HUGE difference!

If that wasn't a fix I would double check the rear brake adjustments. I adjust the brakes out until I hear them rub when spinning the wheel, pump the brakes, and adjust it again until I hear/feel it touch slightly. Excessive brake shoe travel will translate to excessive brake pedal travel.

Mine has auto-adjusters...