i have a 95 tahoe with the same issue low soft pedal. after 2000$ worth of brake work still the same. just picked it up from the local chevy dealer with no clear answer. new rotors,calipers,hoses,rear cylinders,shoes,abs modulator,proportioning vavle,master cylinder. i bled over three gallons of fluid to no avail,i took it to the dealer to bleed the abs modulator.the 95 is all by its self and only gm has the scanner to bleed the modulator.my new snap on wont communicate with it. the pedal is still soft and near the floor and doesnt improve when pumped.if you pinch off both front lines the pedal is hard as a rock ,release either line and the pedal goes to crap. i have had the car for over 380,000 miles the the brakes slowly went to crap with no clear cause over 20,000 miles to the point it isnt safe to drive. even the dealer is scratching his head. they couldnt fix it therefore didnt charge me. they had the truck for 3 weeks and couldnt fix it .if anyone has fixed this problem please let me know

 

I have a 1996 Chevy C2500 P/U It had been setting 3 years. Rear wheel cylinder rubber dry rotted and leaked all fluid from rear wheel reservoir. Replaced rear wheel cylinder and master cylinder. Have bleed brakes, Pedal is hard with engine off, but soft with engine running. Can the ABS module be bleed?

 

I also have a similar problem. I have a 93 k1500 blazer. bought it and brakes were absolute crap. I soon replaced front rotors, clipers, and soft lines. Rear shoes, hardware kits, and wheel cylinders. and also master cylinder. I bench bled the master cylinder and adjusted the rear brakes out to the shoes. I did disable the auto adjust levers because this is a snow plow truck. bled a gallon of fluid through it manually and they still were soft. new master cylinder again. more fluid both manually and with a suction device and had a buddy come by with snap on computer to cycle abs. nothing. after that I replaced the proportioning valve and bled brakes again and still mushy. will pump up but after a matter of seconds without continuous pumping they are soft again.

 

I would try adjusting rear again. When I adjust them, I will turn adjuster until wheel locks tight and you can't turn adjuster anymore, then back off until slight drag is felt.

 

I think my next step is going to replace one of the bleeder screws. very cheap and easy

 

I have a 91 k1500. I've been fighting with the break system for some time now and am totally out of ideas. Back in April I blew a line. I replaced it and still had no pressure after bleeding. So replaced the master cylinder. Still nothing. after replacing the whole break system from front to back it ended up being a frozen adjuster in the rear passenger wheel. In August I lost pressure again. I tried the adjusters, nothing. So I replaced the master cylinder a second time. This worked up until about two days ago. With it still being under warranty i replaced the master yet a third time. I bench bled it, installed it, bled the system. No luck, pedal is still a sponge. Any suggestions?
-Ben

 

same issue....did you ever figure out the problem causing the soft peddle?

 

Are you sure you didn't accidently put front calipers on wrong side? Bleeders always go up. If they're on bottom you'll never get air out.

 

check the brake booster valve it should only let air go one way if its not working brakes will still be squishy parts 30 bucks at oreilysxfir ac delco takes 2 minutes to swap out.