Jamming disc brake.

[torrent99]

I've got a wierd problem with my front disc brake.

When I do a hard brake from speed, it sometimes jams ON! (causing me to almost fall off the bike grrr!)

I've examined the pads and disc, and they look fine. The action appears smooth with no obstructions, it almost like the pads temporarily weld themselves on for a few seconds.

Anyone any ideas?

 

[flecc]

Sounds like there may be an internal angle area on the caliper that's allowing the pads to rotate forward enough to wedge in place. Next time it happens, or if you can cause it to happen, don't jiggle anything, just see if wheeling the bike backwards a fraction once it's stopped releases the clamping action.

If so, it's something on those lines.
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[Straylight]

I've known this to happen with badly set rim brakes when the pad is set out fo alignment with the rim. What happens is that the pad wears unevenly creating an L shape which then grabs around the inner circumference of the braking area.

Could the pads be doing a similar thing around the outer edge of your rotor? Or maybe they're worn enough to cause the mechanism to close beyond what they're designed to do, and jam as Flecc says.

 

[torrent99]

Sounds like there may be an internal angle area on the caliper that's allowing the pads to rotate forward enough to wedge in place. Next time it happens, or if you can cause it to happen, don't jiggle anything, just see if wheeling the bike backwards a fraction once it's stopped releases the clamping action.

If so, it's something on those lines.
.

Yes wheeling it backwards releases the jam. So if I read it right the pads themselves are rotating in the caliper and jamming against the rotor?

So potentially new pads would fix it? Or possibly adjusting the brake so the pads sit closer to the rotor and there's less room to rotate?

 

[flecc]

I think either of those could work, but if the pads are so thin they can jam in, it's possibly best to replace them to get the protection of the extra thickness.

There's nothing to be lost by trying the adjustment first though.
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[Mussels]

I've had exactly the same problem a couple of times, strip clean and reassembly is all that's needed. The pads are probably fine.
Do it soon as in a few days it will get too bad to ride, I had this problem when riding in the snow which wasn't great.

 

[prState]

One of my disc brakes on the Torq 2 will lock up after sitting inside. There is an extreme temp outside/inside difference, which is the only thing I can come up with as to why it happens.

It snaps loose everytime with a good squeeze, so far, so no problems. Just a bit of curiousity.

Otherwise, the one big difference between these and what I'm used to, is these maintain their usefulness much longer without adjustment. Well, and they grab pretty hard too.