Dragging front brakes

[sparkydave]

How much dragging is normal? I took the wheels off to see if I could figure out why the brakes have been squealing. I overhauled the brakes a few years ago; new pads, new anti-squeal shims since it was missing two of them, new master cylinder, cleaned up the front calipers, and ended up replacing the rear wheel cylinders about 2 years ago. The brakes work fine, but when I was checking them out this evening I found the discs drag a bit. I squeezed each side back a little, and the pistons move fine, but when I pumped the brake to seat them the disc still drags noticeably. Anyway, the discs get pretty toasty after a short drive, and I'm guessing since they are hot they are squealing. So, any ideas on why the brakes might be dragging?

 

[spritenut]

How old are the rubber hoses?
Change them every 10 years, they swell up and sometimes burst.

 

[sparkydave]

I replaced all the hoses with flexible stainless lines, and replaced all the pipes at the same time.

 

[Sarastro]

There will always be a little light drag in disk brakes, and of course they will heat up with use, often quite a bit, even if there were no drag. The real question is, how much drag do you have? If, for example, you jacked up the car and gave the wheel a modest spin, does it turn a few times and eventually stop, or stop in a half turn or so? Clearly, the latter is too much drag, but the former probably is OK. This is one of those situations where it would really be best for some experienced guy see it first hand.

From what you've said, though, my guess is that you're seeing normal operation. When brakes drag significantly, you usually have calipers that are binding and so on. Not much else it could be.

Squealing brakes are also the bane of disk brakes; it's not desirable, but not exactly abnormal, either. Obviously, be sure that the anti-squeal shims are in right. Some pad materials are better than others in this respect. That's about all I know. Maybe someone else has more experience exorcising this demon; I haven't had to deal with it much.

 

[nomad]

Make sure that the cut away portion of the caliper pistons are facing down or rather towards the rotating rotor as the car moves forward. Without good information on this I screwed this up once and had trouble with the brakes dragging and heating till I corrected it. They can be turned with a tool that should be available at your local auto parts store.
Kurt.