Perch = International Standard adapter.


My mention about the old styles vs the new styles is based on one particular installation where the perch (adapter) was being positioned too far inboard on account of the perches shape. The flat profile would contact in areas away from the mounting holes. This caused the caliper to line up with one adjuster back off 100%, but the perch and bolts were too close to the disc.

To remedy the problem, since old style Avid IS Adapters are no longer easily available, I had to trace the required profile onto the problem surface, and hand machined those areas away. Once accomplished, things lined up.

Not saying this is your problem, rather it may be something to look at.

As an easy way to test, is it possible to install a thin washer between the fork and perch on the bolt locations? This may bring the alignment and squareness back to the adapter. If it works, you too may need to trim the perches mounting face, or find an old style 203mm adapter.

You mention the forks bonded in place brake mount doesn't look straight, you should be able to check for certain if you try the previous washer trick, just be certain the washers are very close to the same thickness. Mount the perch with no caliper, then using the disc as a reference, check everything for parallel and true to the disc surface. A pain to do, but easy and low time. Might take some photos so as to send to plead your case if the fork is bad.

PK