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Discussion Starter #1
Hi Guys
now the bike is actually alive im working or it being able to stop
the it appears that the front lhs caliper is binding ( dont think its the rhs as when i prise the rhs pads apart the turning resistance is not diminished
so what have i done so far
removed front calipers and cleaned the pins and with silicone grease to let them slide correctly
wiggled the pistons in and out several times with silicone oil to lube the pistons sliding against the seals
they are fairly free
then bled the brakes
front right first both nipples
front left second both nipples
rear last both nipples
no issues to get clean fluid coming out
but....
being that this is linked system and having stood for several years ...
when doing the front middle nipple by pressing the foot pedal ( rear ) at first nothing happened
so i pressed progressively harder and harder and then a kind of pop happened and fluid came out and i continued flushing
now i think i have read that there is a proportioning valve and the secondary pressure piston on the ft lhs side caliper
i have also read that due to mis/ no use this can get bunged up
so my question is
do you think that i have a partial blockage on the fluid return and where could that be????
look forward to being enlightened
paul
 

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Discussion Starter #2
hi Guys
looking around it seems that one cause may be a sticking delay/ proportioning valve
any bets on that?
cheers
paul
 

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... looking around it seems that one cause may be a sticking delay/ proportioning valve
......
paul
Could be and you can test for this. Push all 3 front pistons in. Use the front brake lever to push the 2 outer pistons out and see if the brake is binding. Push the 2 outer pistons in. Disconnect the secondary cylinder from the fork and at the bottom of the push rod. Pump the secondary cylinder push rod a few times and this time only the centre piston should move. Check if the front brake is binding.

By checking this way you are (or should be!) separating the two systems and you can find out which one is causing the problem.
 
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cbr
The other issue could also be hard seals. The design of the caliper relies on the square seal to create enough stiction to roll slightly. The seals flexing back to its original shape is what actually partially retracts the piston back. If the seal has hardened it can let the piston slip instead of rocking and not pull the piston back.
 
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