I ended up having to replace the rear u brake. I couldn't get the tension right and I didn't want this to fail down the road. I bought a black ops rear u-brake mainly because it was available locally. The price wasn't bad at $20. It is melt forged.
It's as easy as pie to adjust the spring tension on these brakes. I learned a few things. One is that the reach on u-brakes is measured from the frame braze on to the opening on the brake. That makes sense but I wasn't certain of that before buying one. The other is that the brake pad that came on the new u-brake was too long. To work right on an old MTB with the u brake under the chain stays, I needed to replace them with the shorter brake pads and holders found on road bikes. U-brakes are a pain to work on and a stand is a big help.
In my experience, u brakes are a solid design. They did not work well for mountain biking because they got gunked up. But they are fine for road riding which is what this bike is going to be used for. I've been riding the bike around and everything is working well. I'll ride it a few more times over the weekend and then ship it off to my nephew who is looking forward to his new old bike.
