I think my rear cilpers are shot and the front brakes are doing all the work,it has new 3 month old pads all around,it had one of the rear calipers replaced,but the mechanic said since I didn/ replace both rears the pressure wouldn't be equal and cause both rear calipers not to work,also they squeak sometimes,I don't know what do you guys think???and I think it has a small brake fluid leak somewhere

 

I thought thats why we bled the brake lines? due to the buildup of air in the lines

 

... if your calipers are operational, (no leaks internally or externally) there is no difference in the pressure between them and they will both work. Unless he takes and does a pressure test at each caliper position, he won't be able to say there is a pressure problem and that is why the rears aren't working.

You may need to have the rears upgraded, as found in the GM TSB on that problem. Basically the piston gets stuck in the caliper and makes them somewhat inoperative. Do a search here and you'll find more info.

Generally, the fronts always do most of the work. Just a fact a physics.

Just make sure of a good brake fluid bleeding. No bubbles, no air, no problem. Just good clean fluid.

 

I agree he was probably trying to get a few more dollars out of you. If your brake lines were not bled than you may have air in them. Air compresses, fluids do not, at least the amount that they compress is so minimal that you can't notice it. If there is air in your line you will experience a spongy feeling and you would probably have to press the pedal down futher to the floor because of the air in your lines compressing.

 

If you pump the pedal, do they firm up, and apply with less pedal travel????

If so, you may just need to adjust your rear brakes. (supposedly the e-brake does this, in actual practice, I don't think so.....)