96 K1500 soft low brake pedal and light

[FlashHole]

Hello. I just joined to thank this website and to share success and hiccup from a thread I found here.

I have a 96 K1500 that doesn’t drive much but is still on work duty. It has suffered from soft brakes and low brake pedal probably for over 10 years after I changed the brake master cylinder. Everything is stock replacement parts.

Fast forward. The booster started hissing while held down so I replaced it. Couldn’t bleed the brakes and suspected I had air from not re bench bleeding the master during booster change. Very little fluid would come out of rear wheel cylinders. Replaced the master cylinder again. Still couldn’t get air out and the pedal is even lower. Too low to be safe. And the service brake light was hard to stay off. Sometimes it would come on while pumping. Sometimes it would turn off while pumping, both during bleeding.

Suspected abs auto bleed and ordered a Foxwell NT630 Plus off amazon. Doesn’t look like it can do the auto bleed on 96 that I’ve seen work on newer trucks. Returned.

Found this thread here. On relieving pressure at the ABS module.

98 gmc yukon brakes help! I've done everything

Swapped a 14 bolt sf in the rear. I had spongy brakes before the swap but figured I'd deal with that after the swap was complete. I decided to put discs in the rear from lugnut4x4.com. bled the crap out of everything and still spongy. Call a brake shop who advises a master cylinder made for 4...

www.gmt400.com

Pressed the button/pin in under the rubber cap on the fender side of the abs module and rebled. Got way more air out the rear wheel cylinders. Pedal hasn’t been this firm in 10years.

Thank you.

 

[Schurkey]

I tried that on my '97 K2500, and didn't get diddly.

The "rubber cap" is on the combination valve, which is bolted to, but not part of the ABS.

You should still bleed the ABS. Probably hasn't been done properly since the truck was built.

 

[FlashHole]

Thanks for the advice. Can you recommend a controller that will work on a 96?

 

[Schurkey]

I have a Snap-On Solus Pro with 14.2 software that will auto-bleed my '97 K2500 with EBC310 ABS. Same ABS controller as yours.

A Solus Pro with 8.2 software will NOT auto-bleed the '97, nor will an MTG2500 with 6.2 software, even though both will auto-bleed my '03 Trailblazer.

I'm told that 10.x software will auto-bleed the later GMT400s with the EBC310 ABS, and that 9.x will, too--but I have no actual experience with those software revisions. I have heard that Snappy added a bunch of functionality to the software packet AFTER they discontinued support for the MT/MTG2500, which was an incentive to dump the '2500 series scan tools.

GM procedure for auto-bleed attached.

 

[FlashHole]

Thank you for the advice and bleed procedure. Im still happy with the pedal as it’s so much better than before. For me it won’t be worth the investment in a snap on scanner. I may ask around a few shops though. I know you are right in that the abs probably has never been bled since 96!! I don’t think I’ve felt the abs kick in the 13 years I’ve had the truck. Probably because it wasn’t capable of locking a tire up!!