sticky calipers

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jjmoto
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sticky calipers

Post by jjmoto » Wed Apr 29, 2015 2:13 pm

Before fitting braided hoses i pumped all the pistons out (Not completely) cleaned them up with brake cleaner & an old toothbrush, cleaned & lubed all pins shims etc so in theory everything should be in good order. Since refitting & bleeding with new hoses theres quite a bit of drag on the discs, it rides fine but its hard work to push the bike around. I read in MCN the day after cleaning the calipers that brake cleaner is not good for piston seals (so why is it called brake cleaner then???)
This is my first experience of stock calipers as my previous Rex had blue spots on when i got it & this one will too when time/budget allows
any ideas?

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Snod Blatter
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Re: sticky calipers

Post by Snod Blatter » Wed Apr 29, 2015 5:57 pm

Corrosion often "grows" in the grooves of the caliper where the seals sit, which pushes the seal on to the piston and can cause drag. It has been the main reason my calipers have needed sorting every time I do them, on several bikes. Sadly in order to get to those grooves you have to take it all to bits..
'95 4NX with K&N filter, Motad Venom cans, YSS PD valves, Ohlins fork springs, 530 C+S, Green CDI, 11/16 radial master cylinder, +30mm jack up dog bones. Enjoyable money pit.

Rich
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Re: sticky calipers

Post by Rich » Wed Apr 29, 2015 8:21 pm

as above, take to bits, remove the seals, clean out the grooves,

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SDN
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Re: sticky calipers

Post by SDN » Thu Apr 30, 2015 1:48 pm

+1 get the pistons out remove the seals and clean all the white crud out with a match stick / cocktail stick, clean up the pistons then re-assemble with rubber grease. Bleed brakes with clean brake fluid and voila - good brakes

jjmoto
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Re: sticky calipers

Post by jjmoto » Thu Apr 30, 2015 6:43 pm

Thanks for the suggestions fellas, did forget to mention though that it wasn't a problem till I cleaned the calipers! ?! Got my eye on some blue spots, just waiting to find out out if my pick up needs a fuel pump rebuild first (£650 + vat) ouch!!!!!!

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