Having a bad time with my dual caliper stock setup - drags after a few applications of the pedal - seems to keep getting air in the caliper - dont have experience with this setup but Donnys book states this setup is the ******* of shovel rear brakes - pistons are not stuck - I have bled and bled and bled and have actually bled by compressing the pistons - they move smooth - has PM M/C with high end PM controls - no leaks anywhere - any comments appreciated

 

Calipers and brake lines look stock but the rotor definitely is not. I would pull the rear tire, take the rotor off and see if it is warped. And if that is the stock brake caliper there will be a date code stamped on the caliper. The caliper is a two-piece unit. It will be stamped on the outside piece.

 

yeah - date code is there - 81 stamp - it only starts to drag after a few long brake holds - it releases if I tap the pedal - thinking I'll have to rebuild the M/C and caliper to rule out any issues with them - or maybe the PM M/C is not correct for the stock caliper

 

That sounds like something is not right in the caliper or MC, probably some gunge clogging up fluid flow, or seals gone squishy. Common problem is the two tiny tiny holes that connect the fluid reservoir to the MC bore clog up and need clearing out with a tiny wire, like off a wire brush.

If your brakes system is to that stage of deterioration, I would fit a rebuild kit to caliper and MC and give the brake hose a good check over too. The hoses swell up after 20 years or so and the hole in the middle becomes restricted. Sometimes they will let fluid pass in one direction but not back in the other.

 

That caliper used a much thicker than usual rotor...like over a 1/4 inch......which that rotor is not...your pistons may be coming out further than they were designed to.

http://www.ebay.com/itm/NOS-Harley-D...RZIZmp&vxp=mtr

 

Yes - that makes sense - I noticed the pistons were out pretty far and I was thinkin' - wtf was Harley thinking with this setup - but then again - many things on HD bikes are like - wtf? so what are my options? I tried removing the rotor and the dang flat socket head screws are totally frozen - an impact driver just bent the snap-on bit - maybe machine up shims? or buy a set of pads and grind off the pad material to make a shim?

 

here is the correct .355 thick rotor - guy wants 50 bucks for it...what ya think?

 

Bet would work better than what you have now...scotchbrite pad on a grinder would make it purdy again...the new $24 ones I posted a link to are .300 thick...not sure what the minimum is for that caliper.

 

Pull them big *** bolts out one at a time and scotchbrite the shanks and put a little anti-seize on them and see what happens. Worked on my 82.