MacGyver

The ol' girl has sat on the sidelines unused for a good 7+ months due to a continuing problem with partially seizing calipers, being out of work for several months and not needing to drive anywhere, and then using the winter beater for the last several months as I rebuilt the calipers. The cause of the frequent seizures was found and rectified (poor seal on overused speed bleeders due to worn out pipe dope, added new pipe tape).

All four calipers were rebuilt, one with a new kit (the one that was truly seizing this time), the rest were rebuilt (using the old seals, just cleaned up and regreased) just because the system was now open and I felt it should be done. However, all four wheels drag quite a bit.

My thinking is the rust has built up so much on the rotors over the last half a year that it will take a few miles of driving to clean them up. Once that's done, I should be good to go and expect no more noise. I'd like some confirmation on my thinking, though. Just don't want to get out there and ruin something else... weather is turning cold, which means I won't be able to do the work myself should anything else go wrong.

Thanks!

cdelena

Sometimes a noise that sounds like a dragging brake and comes on with brake use is actually a failing rear wheel bearing. Some of us have spent too much time looking to free a 'dragging pad' when in fact it is a bearing (and or hub) that gets noisy and obvious at slow speed with a little heat.

MacGyver

cd,

Thanks for replying. The dragging is going on even while the car is on jackstands and I'm spinning the wheel(s) by hand (all four wheels, not just the rears). I've only driven it for a few spins around the culdesac, but the metal on metal noise is embarassing. I'm just wondering if I should drive it for a couple of miles and see if that cleans them up, or if I should take the rims off again and scrub the rotors down with a wire brush.

ahrmike

Mac, pop off the wheel that is 'dragging' - then try check the space between the disk and pad, if you can fit a piece of paper in there its not dragging- if it still makes the noise, cd is right, its most likely a wheel bearing. Have you had problems with "axle pop" ? when you used to go forward/reverse would there be a pop/clunk? If there was, and you didnt do anything, most likely the axle nut torqued itself loose and your bearings got messed up (rear wheels).

cdelena

I would take it out and drive it enough to really work the brakes several times before I took any other actions.

CKit

Including getting into the ABS to shake stuff loose.

MacGyver

Okay, took it for a quick spin... less than a mile, never made it above 40mph. The brake pedal was somewhat soft about halfway through the pedal travel, but tightened up near the end. Several quick pumps brought it to the stiffness I remember, but it would go back to the same way upon the next need to brake. The emergency brake needs to be pulled up higher than normal, too, though only by a couple more clicks (not outrageous).

The scraping sound didn't decrease much, if at all, so I pulled it back in to the driveway. Within that short time span, the rotors on all four corners were burning hot. <sigh> This is new, as only one caliper was partially seizing before I stopped using the car all of those months ago. Since then, all four calipers have been rebuilt, whether they needed it or not.

If it was air in the system, I imagine the pedal would feel soft regardless of the pumping. The fluid is definitely clean, considering I've probably pumped over a gallon of fluid through the system doing multiple bleeds. Could this be something tied to the master brake cylinder (the head end) rather than the calipers (the tail end)?

And wouldn't you know it, I received my bi-annual "invitation" to get the emissions checked mid-January, and it's starting to get down to temps outside I'm not comfortable working in. I need to get this fixed up, and pronto!

Suggestions on what to look for now?

ahrmike

Does it start "grinding" from the start? If you were to get the car cold, start it up, and quickly take it for a short drive would it still grind?

Next, when you do get the "grinds" try put the car up on a rack and crack open the bleeder - does it spray out brake fluid or dribble out fluid? If it sprays out fluid, it means for some reason the brake system is not releasing pressure back to the master cylinder. Maybe theres something plugged on the return line?! If it dribbles out, I'm pretty sure your SOL and gotta rebuild all the calipers AGAIN (my take on this).

ahrmike

By the way, would our ABS system be capable of "blocking" up the brakes from returning to the master cylinder? have you tried disconnecting the ABS connector to prevent it from getting power temporarily?

MacGyver

I can put the car up on jackstands after sitting for two weeks and it will scrape/grind. I can still spin the wheel by hand, so they're not completely seized.

When opening the speed bleeders (cold, haven't tried hot), there's no pressure built up... at least not enough to make the fluid squirt (or dribble) out on its own. It requires a press on the pedal to get fluid flowing out.