Brakes dragging badly after new rotors/pads

[jimincalif]

My son is visiting this weekend and he took the opportunity to use my garage and change his front rotors and back pads on his 2003 GT. Everything seemed to go fine swapping parts, except that now the brakes are dragging badly, front is worse than the back, the wheels can be turned with lots of effort but you hear the pads dragging badly and they start to cook when driven a short distance. After doing all 4 corners he bled the whole system, nothing abnormal while doing this. Brake lube was applied to appropriate areas where the pads are clipped and to the slider pins, it really seems like the system won't release the hydraulic pressure. No problems were apparent beforehand, he drove the car 150 miles on Friday night with no brake issues.

Thanks.

[Chiadog]

I've never seen this happen, so I can't be too certain whats going on. First, why did your son bleed the brakes? I always try to separate tasks with testing in-between to narrow down any subsequent problems. I would now raise the whole car off the ground and evaluate drag at each wheel - then open ONE bleeder and recheck all wheels for drag. If drag persists, remove brake fluid reservoir cap and crack open all bleeders - keep reservoir from going empty and retest wheel drag. If drag persists - problem is likely NOT a brake fluid hydraulic problem. Close bleeders and recheck all hardware and for proper assembly. Also recheck "new" parts for proper application - did he buy the wrong parts?
good luck,
chiadog

[beemerphile1]

I've seen this on vehicles that have had poor maintenance. When he pushed the pistons back it forced dirt and crud in the contaminated fluid back into the lines. The lines could be partly plugged which will only allow the pressure to bleed off slowly.

This is caused by not flushing the brake fluid as recommended. Brake fluid is hygroscopic and absorbs moisture from the air. It will even absorb moisture through the rubber connector hoses.

The first step is a full fluid flush and might involve replacing the rubber connector hoses. The hoses could be plugged and could be collapsed.