Brake piston question
Cruiser
Joined: Sep 2011
Posts: 193
Likes: 2
From: Not too far up the BC border
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 ?
Thread Starter
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Elite HDF Member
Joined: Jul 2008
Posts: 4,762
Likes: 12
From: north jersey
Thanks for taking the time to write those responses brotha. Thats why I love this forum, people take the time to help others.
Anyway, yeah, this is my first time doing any kind of brake work. I bought a mighty vac to bleed the brakes. Thought that and a manual would be all I needed lol, guess not.
When I first took the rear wheel off I noticed that the lower piston (I only have 2 pistons in the rear caliper) was stuck all the way out and the top one was only a little bit out. The brake pads were worn un even.
I then took the pads off tried to push the pistons in to install new pads and that's when I realize that they where stuck. I cleaned the portion of the pistons that was sticking out then pushed them back into the caliper.
I put them back into the caliper, filled with brake fluid, and used the mighty vac to suck the brake fluid from the master cylinder to the caliper. I then operated the foot brake and now the opposite is happening, the top piston is the one that moves out and the lower one is stuck (so I can't get it out to clean it).
Hope I explained it good enough where you guys can u sweatband what I did. Sounds like I might be needing a new caliper. What you guys think?
One more thing, what and where are these pins you guys are telling me to lube?
Thanks again guys.
Anyway, yeah, this is my first time doing any kind of brake work. I bought a mighty vac to bleed the brakes. Thought that and a manual would be all I needed lol, guess not.
When I first took the rear wheel off I noticed that the lower piston (I only have 2 pistons in the rear caliper) was stuck all the way out and the top one was only a little bit out. The brake pads were worn un even.
I then took the pads off tried to push the pistons in to install new pads and that's when I realize that they where stuck. I cleaned the portion of the pistons that was sticking out then pushed them back into the caliper.
I put them back into the caliper, filled with brake fluid, and used the mighty vac to suck the brake fluid from the master cylinder to the caliper. I then operated the foot brake and now the opposite is happening, the top piston is the one that moves out and the lower one is stuck (so I can't get it out to clean it).
Hope I explained it good enough where you guys can u sweatband what I did. Sounds like I might be needing a new caliper. What you guys think?
One more thing, what and where are these pins you guys are telling me to lube?
Thanks again guys.
Ultimate HDF Member
Joined: Dec 2009
Posts: 5,865
Likes: 168
From: Potsdam, NY
I bled my rear brake on my 2008 rocker. I took the caliper off and tried to manually push the pistons back in so I could install the new brake pads. The pistons were freaking almost impossible to push back into the caliper. I eventually pushed them in but it was hard man.
My question is this. Are those pistons supposed to be that hard to push back into the caliper after the brakes have been bled?
My question is this. Are those pistons supposed to be that hard to push back into the caliper after the brakes have been bled?
To remove the pistons pump your brake handle. As the start to come out push back on the one coming out faster. You want them to both push out at the same rate. This is so one does not come out before the other. You want them both far enough out you can grab them with your fingers and pull them all the way out. If one comes out and and the other is not far enough out to grab you are screwed as you will not be able to use the brake handle to push it out further at that point. If you have dual rotors up front you need to do this with both calipers at the same time. Don't grab the pistons with a vice grip or other metal tool as this can mar them causing a brake fluid leak.
Once the pistons are out clean them off completely and check and replace (if necessary) the rubber piston seals.
Seasoned HDF Member
Joined: Mar 2010
Posts: 38,525
Likes: 6,406
From: Honah Lee
You really do not need a pump to bleed a motorcycle since you can reach lever and caliper at same time. Least I can anyway. If you have service manual you may be all right. They make a tool for pulling piston. However if you are careful and wrap rag around caliper you can use hydraulic to pump it out. If both are stuck, pump one and free up. Push it back in and fix it with a board and pump other out. Then you can pull first out. Insure all is clean and no damage or wear you can rebuild with all new rubber and if called out like 4 piston one the special grease for the pistons. The pins someone is talking about I think are the pad pins that are in the 4 piston ones. You can pull these two pins and the pads will pull up out to replace them without pulling caliper. Harley has numerous setups over the years. Not sure if they have ever had a floating system with just one piston on one side and a floating caliper that slides over. In this case the caliper and pins must be greased. Honda puts orings on there floating pin type design with seal boots over them.
Thread Starter
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Elite HDF Member
Joined: Jul 2008
Posts: 4,762
Likes: 12
From: north jersey
Wow, I guess you guys are right man. This brake business is serious, I think I'm gonna take the calipers to the dealership and have them look at it. Last thing I need is to finally get the bike put together and have the brakes fail on me 5 miles down the road. Lol
I'll gladly take more advice on this subject if any of you guys wanna share it.
I'll gladly take more advice on this subject if any of you guys wanna share it.
Cruiser
Joined: Nov 2011
Posts: 180
Likes: 3
From: Jasper, GA
I am over **** when it comes to brakes. If needed or not, I change my rear pads with every rear tire change. The front every other tire change. I take the pistons out- clean with brake fluid and 0000 steel wool. Then I clean the inside of the caliper bores. Dry everything wih air compressor. If one piston comes out faster than another, just push the faster one back in till even and go again. I check all seals, pins, clips, and bolts. Any little thing looks wrong, I change out. You can do this if you take your time. Better yet call a friend that has done this before and you can ride to the bar AFTER the work is done
Seasoned HDF Member
Joined: Mar 2007
Posts: 66,948
Likes: 4,573
From: TOAK western branch
I am over **** when it comes to brakes. If needed or not, I change my rear pads with every rear tire change. The front every other tire change. I take the pistons out- clean with brake fluid and 0000 steel wool. Then I clean the inside of the caliper bores. Dry everything wih air compressor. If one piston comes out faster than another, just push the faster one back in till even and go again. I check all seals, pins, clips, and bolts. Any little thing looks wrong, I change out. You can do this if you take your time. Better yet call a friend that has done this before and you can ride to the bar AFTER the work is done
Thread Starter
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Elite HDF Member
Joined: Jul 2008
Posts: 4,762
Likes: 12
From: north jersey
I am over **** when it comes to brakes. If needed or not, I change my rear pads with every rear tire change. The front every other tire change. I take the pistons out- clean with brake fluid and 0000 steel wool. Then I clean the inside of the caliper bores. Dry everything wih air compressor. If one piston comes out faster than another, just push the faster one back in till even and go again. I check all seals, pins, clips, and bolts. Any little thing looks wrong, I change out. You can do this if you take your time. Better yet call a friend that has done this before and you can ride to the bar AFTER the work is done
I would love to have one of my friends who has done it before but in my circle of ridding friends I'm the only one that pretty much gets this involved in working on the sleds.
I took both calipers to the dealership, the rear one definitely needs to be rebuilt. He's gonna take a look at the front one later and let me know if we need to rebuild it or not. What a nightmare this has been, just glad I found the problem before it became a bigger issue.
With 10,000 miles on the bike I feel more comfortable getting this squared away now.
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Seasoned HDF Member
Joined: Mar 2007
Posts: 66,948
Likes: 4,573
From: TOAK western branch
I would love to have one of my friends who has done it before but in my circle of ridding friends I'm the only one that pretty much gets this involved in working on the sleds.
I took both calipers to the dealership, the rear one definitely needs to be rebuilt. He's gonna take a look at the front one later and let me know if we need to rebuild it or not. What a nightmare this has been, just glad I found the problem before it became a bigger issue.
With 10,000 miles on the bike I feel more comfortable getting this squared away now.
I took both calipers to the dealership, the rear one definitely needs to be rebuilt. He's gonna take a look at the front one later and let me know if we need to rebuild it or not. What a nightmare this has been, just glad I found the problem before it became a bigger issue.
With 10,000 miles on the bike I feel more comfortable getting this squared away now.
Seasoned HDF Member
Joined: Mar 2010
Posts: 38,525
Likes: 6,406
From: Honah Lee
Gland you did not get hurt. Interesting that you 08 with the two piston set up has only 10K on it and they are tight. My 04 has 40K, on the 4th set of pads and I check them them for tightness as described above and they are still like new. However I has DOT 5 and have change it out twice and I never push dirty pistons back into calipers till they are shinny clean on my bike, car and truck. I have a 69 Firebird Convertible I bought new in 70. It had the optional disk brakes..rare back then. They were off the full size cars of the day. I got 4 bad sticking calipers in a row from auto zone years later. Finally gave up and rebuilt the original caliper I had thrown in the corner. They like the master cylinder were unique castings for 68/69. The master cylinder and caliper is all rounded. Later ones were all squared off. Sharp old timer judges catch this.