After trying to bleed the rear brakes using every method known to man, I determined the master is the problem, RATS! TINK
Okay BMW brake expert, put on your thinking caps... So here's the question; should the new piston, with the cup shaped seal, have holes in the front like the old piston? I'm thinking my problem is that with the new piston (no holes) I'm not getting brake fluid flow from the master reservoir to the brake caliper when I release the brake piston and it returns to the starting position? This is the old piston I took out, note the hole in the seal grove This hole goes through to the front of the piston, there are two of them. This is the old seal, note that it is not cup shaped but rather it is rounded like an o-ring... And this is the new piston with a cup shaped seal and no holes under the front seal.
Broke out my rear master issue into a new thread here > http://www.advrider.com/forums/showthread.php?t=864352 TINK
The weekend is finally here and I'm going to push to get PROJECT-S on the road, come hell or high water! Next week there's a local CAFE bike ride in and I really really really want to ride PROJECT-S there > http://www.british-customs.com/readers_ride_show.pdf TINK
She's a RUNNER now! And the crowd went WILD ... Rode PROJECT-S for the first time since April 2011 when I brought her home as an RT. I have not been this afraid to ride a motorcycle since I was 9 or 10 and took that first ride on a Vespa scooter on the farm in Oregon. Brakes!? :eek1 WHAT brakes!? :huh Finally managed to get the rear bled, but the pedal travel seems excessive to me. While this may be considered "normal" it's not very inspiring. Front brakes got better and better the more I used them. I suspect they will need to get bedded before they are up to full working strength. Put 4.5 miles on the odo with a run to the gas station for some California 91 octane junk gas. Pin stripes line up perfectly Putting her away for the day, will install the S fairing tomorrow. TINK
Beautiful bike. Nice job! On the rear brake travel, you might put a block under the centerstand, weigh down the front wheel so that you can spin the rear wheel, then adjust the butterfly nut on the rear brake rod inward enough turns to have the brake start to drag, then back the nut off a few turns. Freeplay at the peddle should be significantly reduced.
I've been following your build all along, CONGRATULATIONS !!!!!!!!!!! That is one classy well built bike.
Not quite caught up here but thought this may help. Those undertank master cylinders are a pain and ATE brakes need everything working right to be adequate. Initial bleeding is one issue, air tends to get hung up in the brake switch, so I loosen the clamp to the frame and put a wood wedge under the front of the assembly to help get the air out of switch. I often let it sit over night with a rubber band or something around the brake lever to get it going.