I have a 1998 K1500 4x4 and recently did a brake job on it. I tried bleeding the brakes and even attempted to hold the bleeder button on the brake manifold with no luck on getting the pedal to firm up. I also used a Snap-On diagnostic tool to make the ABS auto-bleed. Any advice on what to do next? The pedal is still not firm, although the brakes do work slightly better than just after I did the brake job.
I only had the truck for a short period of time before doing the brake job, and there were problems with the brakes themselves that would have prevented knowing if the pedal was soft from those parts or other problems.
I replaced front pads, calipers, rotors, flexible hoses; rear mechanical drum parts and pads, new pistons, added some new fluid but did not flush system.
After replacing the parts, I worked in the front pads by doing easy stops first and then some progressively harder ones. I did the same for the back and also did the backing up and stopping to reset the ratchet device in the rear drum. I also bled all the air out of the lines when replacing the calipers and pistons. When bleeding brakes I used a home made tool to hold the bleeder button from coming out of the manifold and also used a Snap-On diagnostic tool to auto-bleed the manifold. (Where you hold your foot on the brakes while the computer runs the ABS pump.
Still have vaguely soft brakes when pedal is applied slowly and firm brakes when I slam on the pedal.