I just made the swap to F4I front brakes. (mc and calipers) The calipers were pretty nasty when I got them and I decided to disassemble, clean the calipers and I replaced the rubber seals for each piston.

Everything went back together pretty smoothly but now I have an issue.

Im trying to bleed them and on the inside pistons on both calipers are still all the way down and not moving. (and the handle is still mush) I assume its air behind those pistons since Im havingthe same issue on both calipers.

Any suggestions on how I could get that air out? Ive gone through a ton of brake fluid and have used a piston bleeding pump kit and pumping the lever.

Thanks in advance!

 

I'd suggest starting with bleeding the master cylinder... Put a rag around it so you wont spill all over the bike and open up the banjo bolt on the master cylinder... It's a highspot and you usually get a decent sized bubble in there... That big bubble turns it all mushy and once it's gone, bleeding the rest of the system is a lot easier...

 

Perhaps take the calipers off and hold them with the back of the pistons facing up

 

Force the outside pistons back in some and the inside pistons will move out, then bleed again.