My Negative G rear brake has been acting up. Earlier this week, out of nowhere, the rear brake would not release. By that I mean the return spring wouldn't return, so when I would brake it would actuate but then the arms would not release.

I tried replaceing the cable and housing, it didn't help. So after messing with it for awhile I took it to my LBS and the mech put another new cable and housing in, and messed with it for awhile and finally got it to work.

Then today, during the first stage of stage race the brake started to have the same problem again.

Any suggestions?

That caliper can be completely disassembled for an overhaul, while you are doing this you can inspect for warn parts/washers/bushings etc - instructions and parts diagrams are on the zero-g website. It is quite easy to do.

Before you do this, disconnect the cable and verify that it is the caliper that is not returning, and that the brake pads haven not worn a lip on them and are catching on the under/overside of the rim.

Thanks for your input. Your comment
about the brake pads. It jolted a spark in my head, the problem only
occurred with new brake pads.

I guess I need those low profile pad holders. When I replaced the new pads with a more worn down one the brake worked just fine. I'm surprised the LBS I took it to didn't notice that was the problem.

I bet the mechanics at the LBS don't work on Negative G brakes very often. Pad size is not something I would think to check as it's never caused a problem on any brakes that I've worked on.