Front Brake Pistons....
06-23-2009, 03:18 PM
#1
Junior Member
Squid
Thread Starter
Join Date: Oct 2008
Posts: 6
Front Brake Pistons....
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!
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!
06-23-2009, 04:58 PM
#2
Out of my mind, back in 5
MotoGP
Join Date: Nov 2006
Location: Skurup, Sweden
Posts: 6,109
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...
06-23-2009, 06:57 PM
#5
Senior Member
Superstock
Join Date: May 2008
Location: S.Dak USA
Posts: 347
I agree with Tweety, bleed the master cylinder at the banjo bolt,then each caliper starting with the one furthest from the master cylinder.
Stupid question, do you have the calipers mounted with the bleed screw at the top? If they have the bleed screw on the bottom side there will be a pocket of air that will be impossible to bleed out.
Stupid question, do you have the calipers mounted with the bleed screw at the top? If they have the bleed screw on the bottom side there will be a pocket of air that will be impossible to bleed out.
06-24-2009, 06:21 AM
#6
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Squid
Thread Starter
Join Date: Oct 2008
Posts: 6
THanks for the replies. Ill try these tonight and see how it goes.
Last night I did try to push the outside pistons in and the insides still didnt move. Must be a large air pocket in there.
The bleeders are on top.
Last night I did try to push the outside pistons in and the insides still didnt move. Must be a large air pocket in there.
The bleeders are on top.
06-24-2009, 06:34 AM
#7
Senior Member
SuperSport
Join Date: Jul 2005
Location: NYC
Posts: 562
By 'bleeding the master cylinder' do you mean loosen the banjo bolt and allow some fluid to seep out into a rag? Do you guys have a speed bleeder up there? (My brakes have been 'spongy' for a long time - this might be the culprit.)
06-24-2009, 06:39 AM
#8
Senior Member
SuperBike
Join Date: Feb 2007
Location: Portland, Oregon
Posts: 1,051
tim
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