Join Date: Nov 2011
Location: Southeastern PA
Thanked 22 Times in 21 Posts
I did break the calipers apart and thoroughly cleaned everything, you could eat off them, lol.
Lever was still squishy, but did take considerable effort (not like zero amount of fluid in system). I soaked the seals, pistons and bores in brake fluid during assembly. I did remove the calipers from the fork and hung them upside down, while both bleeding and just sitting overnight with the lever tied back against the grip. Now that the air is out, I'm going to remove the bleeder nipples and try a blast of air directly into the nipple hole and see if that moves them.
I've rebuilt these before and never had anything like this happen. Weird.
I'd be very wary of using compressed air with brake fluid in the system. DOT 3/4/5.1 is one of the best and fastest acting paint removers available. Feel free to ask me how I know. I'd also be wary of forcing fluid into the caliper with the lever ziptied for the same reason. Keeena may have more to say on this.
As keeena notes, upside down is not what you want. While I can't visualize your caliper at the moment, the idea is to get the bleeder pointed straight up relative to the air pocket. Tapping and rotating the caliper can also help. Another thought is to use a syringe to suck the fluid through the system.
'61 Clubman's Gold Star, '13 Duke 690, '13 Daytona 675R (track bike), '17 Superduke GT, '18 Street Triple RS