Hi ive got an 04 GC lerado special edition 130k miles that has had a squishy brake problem that im not figuring out. I have replaced all four rotors and pads it was very needed. And I have bled all four calipers with no luck. But I did take my jeep to a shop to get the transmission filter and fluid changed again and after I did that, for a while my pedal was firm again for about a week then went back to its "normal" feel again.

Am I looking at a brake booster or master cylinder problem. Or is it a vacuum issue? Please help.

 

Disconnect and plug the vacuum hose to the brake booster and try driving it. The pedal effort will be harder, but if the "squishyness" goes away, it's the brake booster. Otherwise, you still have air in the lines or a internal leak in the master cylinder.

 

Thanks I will try this today and get back with ya.