I am currently working on a Diamond back Apex with a rear U brake And I have managed to screw it up. Since this was a sale bike for the Bike Exchange I took it apart for cleaning and thought I should pull the U brake even though it was working fine. In doing so The drive side arm would not come off the stud. Also the internal spring came out. Nothing I tried seemed to work in putting it back together. I tried inserting the spring with the short end in and out , Used the hex wrench to twist the spring. When I replaced the plastic cap and bolt the spring would not engage and wind up the arm. Then I pulled the other arm to see if I had done something wrong an managed to break the plastic cap , making it unusable.

This is a beautiful bike which saw little use in its 30 plus years and I would hate to think I have ruined it over a plastic cap. I looked on E bay and there are lots of u brakes sold for BMX bikes that look like they might work .

Has anyone else gotten themselves into this fix and if so how did you work around it. Also, Is there a tutorial on how to remove and replace these brakes. This is the second u brake I have worked on. The first , a Yellow Diamond back Assent I did a few weeks ago , went back together without incident. We have tons of brakes of other types in the shop parts bins but no U brakes.