Frame is about to get gusseted so that would be the time to replace it (if necessary). Just not sure if the pivot was perfectly flat along its length when new (or if it had a very small step to match the bushing).
Thx.
Mike, I'm sure they were a constant diameter cylinder with a 12mm diameter.
As a machinist, I'd just whittle out a new pin with the appropriate internal threads and replace that worn pivot, but another idea came to mind as well.
The current model Yamaha YZ's use a large shoulder bolt.
The bolt has an 8mm threaded section that goes into a flat surface on the frame, then it has a 14mm smooth cylindrical section that serves as the pivot.
The beauty of that system is that a new bolt means you have a fresh pivot surface.
The bolt goes all the way through the tab on the frame and the tip of the threaded portion is drilled for a keeper clip (or safety wire).
The YZ bolt would be too large (14mm diameter), but perhaps another bike like a Suzuki or Honda uses a 12mm shoulder bolt on the brake.
Also, if you can find a metric shoulder bolt with a 12mm diameter smooth shoulder, you could drill and tap the frame and set it up like the Yamaha.
When the shoulder wears out, you replace it. It's much less likely to wear though, as most industrial shoulder bolts are hardened and ground.
This product from McMaster Carr Supply is on the right track, although the head of the bolt is pretty tall:
(The threaded portion is M10-1.5mm, the shoulder is 12mm, and the length is 25mm).
Any supply house like Tacoma Screw Products or Fastenall, or Grangier, or the local place should be able to get a metric shoulder bolt.
https://www.mcmaster.com/92981a404If none of that makes sense, check out this diagram for the Yamaha system on the 2005-2019 YZ250 and YZ125 at the link below:
Items #2, #3, and #8 are the pivot-bolt, o-rings, and the retention clip.
https://www.motosport.com/dirtbike/oem-parts/yamaha/2010/yz125/stand-footrest