96 Tahoe Spongy Brake Pedal

[lou4LSU]

brake fluid is hydroscopic (I believe that's the right word) but it will absorb water if u put a cup of water and a cup of brake fluid next to each other over night the water will be gone the next day due to the brake fluid taking it in. im having a similar problem with my 96 4dr 4wd. pedal is soft and you can hear a woosh when you quickly press it. pedal goes about halfway before I get a decent reaction and can be pressed all the way to the floor without much reaction unless going slow. just replaced all pads and shoes but problem was there before but seems worse now. going to do a full flush but any ideas are welcome.

 

[SunlitComet]

properly adjust the rear shoe adjusters. check for bulging rubber brake lines. get the abs system cycled a few times to see if the issue changes. some would say that the whoosh you hear is the complication of the issue going over ones head but it it the air movement in the vacuum brake booster and it is normal to hear it.