Front brake caliper compatibility

[Jazzzzz]

Just want to double-check, but does anyone know for sure if the front caliper from a 98 will bolt straight on to a 91 without swapping the master cylinder?  I've run a few searches and this seems to be the case, but I wanted to double-check.

The front brakes on my bike are dragging, and I can't get them fixed.  There's a front caliper from a 98 on ebay right now that would be cheaper than a rebuild kit for what I already have, hence the question.

Thanks!

[dgyver]

Yes. There was an improvement which added a clip or something like that. Pads may have changed too. But the mounting is the same.

[Blueknyt]

im currently working on an adapter plate to bolt a Katana 600 4-piston caliper onto a GS fork leg. will let everyone know when i get it mounted.

[Jazzzzz]

The caliper I ordered from ebay showed up, and it's in worse shape than the one that's already on my bike -- guess that's what I get for $10 and shipping!

I took my original 91 caliper apart, pulled the pistons and o-rings, cleaned everything out, re-lubed with DOT 4 per the clymer manual and re-assembled.  From what I could tell from my disassembly of the caliper, the smaller of the two pistons was not retracting the same amount as the large piston when I let off the brake lever.  When cleaning and re-assembling, I went so far as to very lightly wet sand the small piston with some 2000 grit paper to remove any burring or brake dust that might've adhered to it, but it apparently did nothing.  The brakes do grab and release just fine. but they're very lightly scraping. The wheel will turn 1-1.5 turns on its own before it stops, and the rotor is not warped, grooved, scratched, etc.  I found an old post by dgyver that suggests pushing the front wheel up against the wall, loosening the axle a bit and bouncing on the forks a few times, then re-tightening etc.  I'll do that tomorrow when I put in my progressives - are there any other things I can try tomorrow?

edit to say that I've carefully bled the brakes each time I've tried fixing them, with a vacuum bleeder.  There's no mush in the brake feel, I don't think I have an air leak anywhere.  I've been using fresh brake fluid from a sealed container also (I have 3 half-empty bottles of fluid in my garage )