Chevrolet Repair Questions? Ask a Mechanic for Answers ASAP
Was this an issue prior to the caliper replacement?
Ok, this may seem silly, but please check and make sure the bleeder screws on the calipers are pointed up. What I see a lot is the calipers accidentally on the wrong side. When this happens you can bleed them and you will have a great pedal when the vehicle isn't running, but start it and the pedal drops. This is because the air rises up to the top. If the bleeder isn't up top, then there is still air in the calipers. It is easy to swap sides by mistake.
Please look at this and let me know.
As far as simple mistakes that is really it.
Now, this system should be cross bled. Starting with the rr, lf, lr and rf. In that order. If this has been done or doesn't resolve the issue, then I would line lock the brake hoses on the new calipers. Then start the truck and press the brake pedal and see if it's firm. You should not have to bleed the ABS unless you let the master cylinder run dry while changing the calipers. It is however quite possible you got a bad replacement caliper. If you line lock them and the pedal is firm, remove them one at a time until the pedal drops to the floor. Then I would replace that caliper. If the pedal is soft right from the get go, then you will need to start by bleeding the master cylinder. This can be done right on the truck. I suspect however you are going to find one of the new calipers defective or a brake pad not lined up properly.
Check these and let me know.
Did you try line locking one of the front to make sure one of the calipers is not the cause?I know of no way to bleed the system without the scan tool, but just don't feel confident it's the problem. I have seen so many of the rebuilt calipers have problems I feel it's an important step.
Ok, take a pair of vise grips and pinch off the rubber hoses to the calipers. There is also a rear line to the axle. Do them all at the same time and start the truck. If the pedal feels good, then you have eliminated the master cylinder and the ABS as the culprit. Then, remove one line lock at a time. When the pedal drops to the floor, you have found the bad part. Then, if you find it's one to the calipers, swap it with another.