Is there such a thing as a partially sticking disc brake caliper?
Our Fusion ate up the rear left brake pads early - the rest of the pads on the car are not even 1/2 gone, but those were down to the metal (at about 46000 miles). Everything seemed loose, and the wheel was a bit stiff but turnable by hand (even just grasping the studs) so I put it down to just one of those bizarre things and threw on new pads.
It’s only been about 3 weeks and that pad (especially the outside one) is noticeably more worn than the other side - about 0.1" more worn, it’s probably not going to make 10,000 miles at this rate, despite the
fact that the other brakes are half worn at 46,000 miles (about what I usually expect).
The sliders are absolutely free, everything looks clean, the handbrake
cable releases all the way to the stop when it’s released. It felt pretty snug when I took the brake off the first time, but after playing with it, putting everything together again and testing
applying and releasing both the hydraulic and the hand brake, the left and right sides seem to release about the same. Could be they only jam up under driving conditions though?
I put a squeeze-down clamp in the caliper with 1/4 inch of space and had an assistant press the pedal - it went out to meet the clamp, and when released it retreated slightly. The clamp couldn’t push it back but these are automatic adjusting calipers, I used a tool to screw
them back in again. The other side appeared to act about the same,
though I think it’s possible that it retreated farther when released
than the “bad” side did.
Whenever I’ve had stuck calipers in the past they’ve jammed hard, to the point where the disc was almost smoking hot, you could feel the heat from the wheel, and I had to pry the caliper off the rotor with a
crowbar. That’s why I shrugged it off before.
I drove around for about 10 minutes before investigating, doing everything from the mildest braking to hard braking, and that rotor didn’t seem overly hot (any moreso than the others).
I’m thinking it’s a sticky (but not totally stuck) caliper, but I figured I’d ask here before spending $200 on a new caliper.
Yes, it is possible.
Remember that it isn’t just the sliders that can stick. You have a piston in there, and a “square cut O ring” providing a seal and drawing back the piston slightly. That O ring can deteriorate. And also a flexable line at the caliper can collapse (hint hint).
If you cannot tell a difference when resetting the piston with the reset tool, I think you should look at the flex line. These break down internally, and have been known to cause a ‘check valve’ type of condition where the fluid pressure is not allowing the brake caliper to release, or to release slowly. And, it would be much cheaper than a reman caliper.
The flex line sounds like a reasonable guess. Previously when I’ve had stuck calipers it was the actual caliper that was stuck, frozen right in place, even after removing the hydraulic line. This isn’t acting like this but there’s clearly something going on. The flex line sounds like a reasonable thing to try since it’ll be relatively inexpensive.
On my Maxima the rear brakes were actuated by the parking brake by rotating the piston in the caliper. As time went on that had the effect of continually pushing the pads lightly against the rotor, and the rear brakes wore out much faster than the fronts. At first I was completely baffled, but then the whole thing dawned on me when I had to screw the piston back into the caliper to install new pads. It sounds like your set-up is similar. I’d check the hand brake (parking brake) cable system carefully, on the chance that it’s pulling and rotating the piston in the rear left more than the rear right.