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Brake piston removal


Chris79
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Hi all


Have noticed brake performance has reduced a little, doubtless because I have not cleaned them over the winter.... (lesson learned).


So I have removed the caliper to give things a very thorough clean and also bought some new seals as I may as well do the job properly. The Thundercat has the infamous Yamaha Blue Spot calipers. Three of the pistons can now be turned and removed by hand, one however is not having it at all. It is fully cleaned externally as far as I can so some crud is between piston and caliper that I can not yet get at. So how to get the little fecker out.


The various piston removal pliers have mixed reviews and the only way I could use one of the better quality tools (ie the Lazer one) would be to remove the blue spots so I can get that tool in as the blue spots caliper can not be split.


Can anyone recommend one of the plier type tools that does ok with stubborn pistons or are they a waste of time for that? I ought to buy some anyway for turning/cleaning the pistons in the future. Is there something I could soak the caliper/piston in to try and break down the crud? Even though I am replacing the seals I am bit concerned about exposing the caliper internals to all sorts of chemicals and stuff. Any suggestions very gratefully received.


Chris

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Use the hydraulics to remove it.

Put the 3 pistons back in. Reconnect hose.

Use a block of wood to prevent 2 of the pistons moving out again.

Clamp the remaining free one with a g-clamp.

Punp the master cylinder to push the tight one out.

Be careful near the end because it could pop out spraying fluid allover the place.

Sometimes if you are lucky you can remove it using compressed air instead of connecting to the bikes y=hdraulics.

Depends how tight it is.

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Use the hydraulics to remove it.

Put the 3 pistons back in. Reconnect hose.

Use a block of wood to prevent 2 of the pistons moving out again.

Clamp the remaining free one with a g-clamp.

Punp the master cylinder to push the tight one out.

Be careful near the end because it could pop out spraying fluid allover the place.

Sometimes if you are lucky you can remove it using compressed air instead of connecting to the bikes y=hdraulics.

Depends how tight it is.

Yep, this is all great advice. What I recently did to grip the more stubborn pistons was use a folded up piece of rubber inner tube and ordinary pliers. You only need to protect the outer surface of the pistons and this only works if everything is absolutely grease and brake fluid free so a blast of brake cleaner beforehand should help. If you flick back to the recent thread "Brake lever travel" you will find loads of brilliant advice that was a great help to me when I stripped-down my calipers a couple of weeks ago. You might want to get a tube of Red Rubber Grease before you reassemble . Good luck..

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Bike pump/ airbed compresor with the airbed attachment pressed into the inlet hole ..

DO NOT USE A AIRLINE unless you want to hurt yourself or someone ..the pistons fly !

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DO NOT USE A AIRLINE unless you want to hurt yourself or someone ..the pistons fly !

 


I always use an airline!


Never had one fly out or hurt someone


But then I know to place something in the calipers to stop them coming all the way out :lol:

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DO NOT USE A AIRLINE unless you want to hurt yourself or someone ..the pistons fly !

 


I always use an airline!


Never had one fly out or hurt someone


But then I know to place something in the calipers to stop them coming all the way out :lol:

With opposed piston calipers the pistons can't fly out because the other half of the caliper is in the way.

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DO NOT USE A AIRLINE unless you want to hurt yourself or someone ..the pistons fly !

 


I always use an airline!


Never had one fly out or hurt someone


But then I know to place something in the calipers to stop them coming all the way out :lol:

With opposed piston calipers the pistons can't fly out because the other half of the caliper is in the way.

 

No but they come out with a force that will split skin and crush misplaced fingers

Young yts in daihatsu garage i worked in learnt the hard way .. fingers curled in the caliper ... applied the air .lost the tips of two fingers due to the damage the pistons created

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I always use an airline!


Never had one fly out or hurt someone


But then I know to place something in the calipers to stop them coming all the way out :lol:

With opposed piston calipers the pistons can't fly out because the other half of the caliper is in the way.

 

No but they come out with a force that will split skin and crush misplaced fingers

Young yts in daihatsu garage i worked in learnt the hard way .. fingers curled in the caliper ... applied the air .lost the tips of two fingers due to the damage the pistons created

Ouch! Point taken.
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I normally put a large Allen key in the gap between the pistons (after removing the pads) and then pump the brake lever until all the pistons touch the Allen key.....then remove the Allen key and pump the pistons out the last bit...... :wink:

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I normally put a large Allen key in the gap between the pistons (after removing the pads) and then pump the brake lever until all the pistons touch the Allen key.....then remove the Allen key and pump the pistons out the last bit...... :wink:

I just took the pads out and put the calipers back on the bike . Pumped the lever until all 12 pistons were on the disk ( top up fluid ) then took the calipers off and drained and split them. finally I pulled and twisted each piston out using pliers and a piece of rubber .

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