Hi guys,


So, as I've started to do a lot of stuff on my bike, I have realized that was time to change brake fluid too.
Old brake fluid was completely brown. Can't remember when was the last time I have changed it.
After changing it - my fault not to do it after- I decided to take a look on calipers and I have found pistons were dirty.
So I grab a toothbrush and started cleaning them. While trying to clean them better, I have pushed on the lever and one of the pistons pop up so I took everything out ( splited caliper) and tried to take the rest of the pistons.
With the air compressor was easy to take one of them ( the other one was already out) but the other two's were completely stuck.
I have pour some wd40 let it work, tried with air again but nothing.
So I caught some pliers, I put some electric tape to avoid injuries to the piston and started working....
Piston remained stuck, couldn't take it and I have injured it!!!
I have ordered a new set now, but takes ages to arrive.
So...what would you suggest me? First to take them apart, and then...what about using old piston with some tears until new ones arrive.
By the way, I have tried to put the piston back ( the one that pop up) and I have found it quite complicated too!! Difficult to install ( I have ordered new seals as well)


I hope that somebody can give me some tips.


Cheers guys,
Lisandro


ps. I have used a piece of cloth too to protect pistons, but still!

 

Maybe sand with very very fine sand paper or polishing pad the old pistons that are out and put them back in. Refill the fluid and use wood spacers in place as stoppers to keep the removeable pistons from coming out but allow the stuck one to start moving. You would need to work in stages, allowing each piston to move a little working you way around til all of them are out the same distance. You would be using your brake lever to do this. As long as they are all out the same distance and finally one actually comes all the way out, the other ones should be easy to pull out by hand or air pressure. Before you put everything back, polish the piston bores and pistons and clean with brake cleaner and brake fluid. Dont get anything like water or WD40 in your calipers after cleaning. When installing new pistons and seals only use brake fluid as a lube to install. Happy trails, CMF

 

Also if you used big pliers to try and/or get piston out, they are aluminum I believe, maybe you squeezed too hard and oval/egg shaped the piston, and it isnt round anymore which would make it hard to install back in the caliper.

 

Thank you coalminer Frank!


Directions were quite useful. I have reset everything back, but now Im having other issue.


I have refilled the fluid, tried to bleed it, but still, I have no pressure on the lever.


Fluid doesn't come out from de seals. While bleeding it, came out with a little help (sucking from a hose on the bleeder) expecting to take all the air. But anyways, no pressure.


System looks quite simple, but I cannot realize what is my mistake.

 

There has to air in there somewhere. I assume everything is mounted back in place and the bike is ready to ride. Except for bleeding the brakes. What I would do is remove the caliper from the bike, place a thick wood spacer between the pads so you dont accidently do what you did earlier. Turn the caliper around and around trying to get any trapped air to the top where the bleeder is. Or even up the line to the master cylinder. Then mount up are bleed some more. Hell, even try shaking the handle bars back and forth trying to dislodge the air.

 

Try to bleed at the top banjo bolt. I know it helps with bleeding the clutch on my magna

 

i replaced all of the pistons and seals on my cbr1000f,,you need a bit of patience and do make sure as all the seal seats are pristine,,you must ensure all of the crud is removed,,,as for bleeding just keep pumping away and eventually you should start to feel the pressure.