I have a 01 blazer.

I am in the middle of changing my brake pads and I have a difficulty getting the pistons to all the way back. I pressed on them and at first they all went back until they were both half an inch away from going in fully. Now whenever I press on one of them it goes fully in and the other one sticks right out.

Am I supposed to disconnect the brake fluid lines? open the bleeder? or should I replaced the caliper?

 

Plan on replacing the rubber brake hoses to each caliper. Sounds like they have collapsed on you. This might sound kind of strange and they probably look okay but this sure sounds like the culprit.

I had this happen to me but I didn't have the time to replace the hoses with stainless ones so had to replace with the same type. If you have the time, get the aftermarket stainless ones.

Of course, this means you will need to bleed the system afterwards. Just make sure you have some help to make sure you don't drain the ABS module dry when you are changing out the hoses. If that happens you'll need to bring it into a shop to have the bleed done unless you have the tools and knowledge on how to do it.

 

I ended up fixing the problem without having to change the brake hoses.

What I did was I had someone press the brake pedal to the floor as I opened the bleeding valve at the top as I pressed the pistons back and they both went back fully while brake fluid gushed out. Then I tightened the bleed valve and had the other person release the brake pedal. I did this with both sides.

Whats a good indicator that there is still air in the system? I took it for a drive and the braking was just like how it was before changing the pads.

 

Brake fluid is cheap, buy some and bleed your brakes

 

If you do the brakes one wheel at a time, you won't have that problem. When you move the piston in, the fluid will be pushed back to the master cylinder, rather than push the opposite piston out. "Technically" the flex line should be line locked and the bleeder opened before moving the piston back in. This pushes the nasty fluid in the caliper out of the system, and keeps it from entering the ABS unit and master cylinder. The calipers needs to be bled after they are installed. With this system, they must be gravity bled first, don't pump the pedal, and don't let the master run dry. After gravity bleeding, slowly press and release the pedal until it's firm, don't pump it rapidly. Then hold pressure on the pedal to bleed the last bit of air out.