Brake piston question
Thread Starter
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Elite HDF Member
Joined: Jul 2008
Posts: 4,762
Likes: 12
From: north jersey
Thank you guys. I'm going downstairs to brave te heat and try to clean the pistons. I have both wheels off te bike right now so I'll learn on the rear brake and then move on to the front.
Road Captain
Joined: Jun 2010
Posts: 502
Likes: 66
When you try to push the piston back in is the bleeder open? it should be.
Crack the bleeder open then try to push the piston back in should go real easy.
You will loose brake fluid this way but you bleed the brakes after the caliper is back on the rotor with the new shoes installed.
It sounded like you were trying to push the piston in with the bleeder shut
Crack the bleeder open then try to push the piston back in should go real easy.
You will loose brake fluid this way but you bleed the brakes after the caliper is back on the rotor with the new shoes installed.
It sounded like you were trying to push the piston in with the bleeder shut
Thread Starter
|
Elite HDF Member
Joined: Jul 2008
Posts: 4,762
Likes: 12
From: north jersey
When you try to push the piston back in is the bleeder open? it should be.
Crack the bleeder open then try to push the piston back in should go real easy.
You will loose brake fluid this way but you bleed the brakes after the caliper is back on the rotor with the new shoes installed.
It sounded like you were trying to push the piston in with the bleeder shut
Crack the bleeder open then try to push the piston back in should go real easy.
You will loose brake fluid this way but you bleed the brakes after the caliper is back on the rotor with the new shoes installed.
It sounded like you were trying to push the piston in with the bleeder shut
I just realized I don't have any brake fluid. Have to run to the dealership to get some so I can force the pistons back out and clean them.
Road Captain
Joined: Jun 2010
Posts: 502
Likes: 66
When the bleeder is closed it is a closed system neither air or fluid can escape.
When you try to push the piston in with the bleeder closed you are trying to compress either liquid or air whatever you have in the system . Open the bleeder and try it piston should go right in This is a so so example but take a plastic bottle with a screw on lid, screw the lid on and try to collapse the bottle it will be hard to do, now take the lid off try to collapse the bottle easy huh.
When you crack the bleeder if you have brake fluid in the line it will squirt out when you compress the piston so be careful where you aim it.
When you try to push the piston in with the bleeder closed you are trying to compress either liquid or air whatever you have in the system . Open the bleeder and try it piston should go right in This is a so so example but take a plastic bottle with a screw on lid, screw the lid on and try to collapse the bottle it will be hard to do, now take the lid off try to collapse the bottle easy huh.
When you crack the bleeder if you have brake fluid in the line it will squirt out when you compress the piston so be careful where you aim it.
Seasoned HDF Member
Joined: Mar 2007
Posts: 66,948
Likes: 4,573
From: TOAK western branch
When the bleeder is closed it is a closed system neither air or fluid can escape.
When you try to push the piston in with the bleeder closed you are trying to compress either liquid or air whatever you have in the system . Open the bleeder and try it piston should go right in This is a so so example but take a plastic bottle with a screw on lid, screw the lid on and try to collapse the bottle it will be hard to do, now take the lid off try to collapse the bottle easy huh.
When you crack the bleeder if you have brake fluid in the line it will squirt out when you compress the piston so be careful where you aim it.
When you try to push the piston in with the bleeder closed you are trying to compress either liquid or air whatever you have in the system . Open the bleeder and try it piston should go right in This is a so so example but take a plastic bottle with a screw on lid, screw the lid on and try to collapse the bottle it will be hard to do, now take the lid off try to collapse the bottle easy huh.
When you crack the bleeder if you have brake fluid in the line it will squirt out when you compress the piston so be careful where you aim it.
Seasoned HDF Member
Joined: Mar 2010
Posts: 38,592
Likes: 6,435
From: Honah Lee
Rebuild time. Never ever push in before pulling caliper. Pull pads, slide thinner object in and then use brake pedal or lever to push pistons out further. shoe shine with rag and then push in. When rebuilding, Harley is only one that calls out a special grease for lubricating pistons before replacing.
Former Sponsor
Joined: Aug 2005
Posts: 10,968
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I use Brake Cleaner (who'd a thought?) and a tooth brush to clean them off. It takes just a few minutes to do. The pistons do not need to come all the way out to be cleaned but the further they are out the better. Then push them back in and put the pads back in. If you are having issues pushing them back in you can always take the top off the master cylinder to make it a bit easier, just don't mess with the lever while the cover is off. If you have already bled the brakes and the lever is firm it is unlikely you will need to bleed them again unless you mess with the lever with the top off the master cylinder and cause them to suck in air.
Thread Starter
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Elite HDF Member
Joined: Jul 2008
Posts: 4,762
Likes: 12
From: north jersey
Well I just went down to my garage and tried to mess with my rear caliper again.
I put some brake fluid in the reservoir to get the pistons to come back out so that i can clean them and Now the top piston comes out but the rear one doesn't! Yesterday the bottom piston was the only one that came out, the top one didn't. I ended up cleaning the bottom one pretty good and pushing it back into the caliper.
WTF!!!!! I can't clean the pistons unless I get them all the way out!!!!!!
In one of the previous threads someone mentioned that the pistons can come out far enough for them to pop out of the caliper. I'm thinking about doing that so that i can clean them and clean the housing where they sit. Does this sound like a bad idea to you guys ?
I put some brake fluid in the reservoir to get the pistons to come back out so that i can clean them and Now the top piston comes out but the rear one doesn't! Yesterday the bottom piston was the only one that came out, the top one didn't. I ended up cleaning the bottom one pretty good and pushing it back into the caliper.
WTF!!!!! I can't clean the pistons unless I get them all the way out!!!!!!
In one of the previous threads someone mentioned that the pistons can come out far enough for them to pop out of the caliper. I'm thinking about doing that so that i can clean them and clean the housing where they sit. Does this sound like a bad idea to you guys ?
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Seasoned HDF Member
Joined: Mar 2010
Posts: 38,592
Likes: 6,435
From: Honah Lee
Rebuild time. Never ever push in before pulling caliper. Pull pads, slide thinner object in and then use brake pedal or lever to push pistons out further. shoe shine with rag and then push in. When rebuilding, Harley is only one that calls out a special grease for lubricating pistons before replacing.
Last edited by Jackie Paper; Jul 17, 2012 at 08:28 PM.