I assembled the rebuilt caliper, using the pads that came with it because they didn’t have much wear. I hooked everything up, filled the master cylinder with DOT 4, and attempted to bleed the line. After 30 minutes or so, the fluid in the reservoir hadn’t dropped, at which point I naturally assumed that I had done something wrong. I took everything off the bike and stripped the master cylinder down again — tearing the new dust boot in the process. GRRR!
Even more frustrating, I hadn’t even needed to disassemble it. Nothing was amiss inside and a simple bench test would have demonstrated that it was sucking and puffing well enough. Like I said, it’s been a long time since I’ve done this.
Like so many other points along this journey, the path forward was to spend money on the proper tool. I ordered a $40 vacuum pump from Amazon yesterday, which amazingly was waiting for me when I got home from work.
With a bit of negative pressure from the pump at one end and some pumps on the brake handle at the other, I was in business! The used pads and disc will need to bed in, at which point I will probably bleed it again, but that’s way down the road. For now, the brake lever feels firm, and the caliper releases properly when you let off, so I’m calling that a win.
I’m not sure how to address the ripped boot. It seems silly to order another whole rebuild parts set just for that little rubber part, especially when the system works fine now. In addition to my dust boot issue, I discovered some unpleasant aspects of the Eastwood brake paint. It might be brake-fluid-resistant, but it’s not totally impervious to it. During all my efforts, I let brake fluid get on the the painted exterior of both the master cylinder and caliper. The paint hazed almost immediately. I was able to buff the caliper back to an acceptable finish where it shows, but when I did the same thing with the master cylinder, the black OE finish started showing through. So it will need to get a repaint at some point. However, cosmetics in general won’t be much of a concern to me until such point as I have a running, rideable bike.
Another minor annoyance: when I went to attach the clip that keeps the brake line from chaffing against anything, I discovered a broken screw in the bottom triple clamp. Getting a drill in there will require taking the front wheel off, so that’s something else I’m deferring until later.