Brake problem 2005 GMC 1500 Sierra

I just had all my pads and shoes replaced, all 4 wheels Drum in back, disk in front. I have less than a hundred miles since this was done. Then today as I was returning home from a 20mile trip my brakes locked up and I came to a skidding stop tires squealing. I was in my development when it happened so I was not going very fast. It repeated itself each time pressed on the brake peddle more than a slight bit. it would go from a slight slowdown to full lockup.

About 30 mins later, I drove it over to the dealer (only a few miles) at a very slow rate and on the shoulder. I used the emergency brake a few times to stop and it did not make it lockup, but then the last turn into the dealer another complete lockup using the emergency brake.

Any ideas what would cause this? Any way to know if they caused the issue when they replaced the pads?

Yes–I think I know what the problem is. It has happened to me. The inside of your brake line is rubber. As the rubber deteriorates, it sometimes develops a flap that acta as a one-way check valve. So, you step on the brakes and the fluid flows to the slave cylinder. Then, when you let up on the brakes, the flap opens and the fluid cannot flow back toward the master cylinder, so the brakes remain locked. This problem has nothing to do with the work you had done. New brake lines are needed. And, it’s your brake pedal, not peddle you are pressing on.

pull the MC lid off and make sure some idiot didn’t put the wrong fluid into the m/cylinder. Dead giveaway is the diaphragm being all puffed out.

I had the brake lines eat through a couple years ago. They replaced most of them but not all I think they were able to patch into the ones going to the back instead of completely replacing them., They may have just replaced the hard lines and not any flex lines, I’m not sure. Is this rubber, just in the flex lines?

Rubber will be from every corner of the frame to the caliper/drum. Everything should be steel if I remember right.

Considering it did it with the e-brake and you have rear drums it kinda sounds like the wrong shoes were installed or were installed backwards.

When it all comes apart, something should look chewed up.

Sounds like an ABS sensor to me. Usually should throw an ODBC error, but not guaranteed.

Caliper staying closed up, or abs sensor failure. You can easily pull the fuse for the brake and disable the abs and see if the problem goes away. If so… Then it’s abs related.