removing pistons from caliper

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reds
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Re: removing pistons from caliper

Post by reds »

will see how i get on tommorow in my lunch hour - have compressed air at work, but not many fittings for the guns - fingers crossed !
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Simon2million
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Re: removing pistons from caliper

Post by Simon2million »

if u see the post viewtopic.php?f=87&t=9075

thats my brakes rebuilt, im on placement this year at a company that is dedicated to restoration. i managed to get most of my pistons out with the compressed air, Tip is to wrap a rag around the blow nozzle so that it seals well to where u are blowing in and doesn't leak back as much. however the really sized buggers needed a greese gun, as mentioned already, just a hand pump gun should suffice. Remember that the very tips of the piston never actually go past the working seal so it is safe to grab the piston here with grips, worst case will be cosmetic damage but should not affect braking performance. Stainless steel ends are £7 per fitting , the best price i could find ( demon tweaks want £14 ! ) and i can get lengths of hose posted and even made to length if required, but best to make the ends up on the bike so u can use the natural curve of the hose to your advantage, stainless steel bolt pack is available on ebay ,full set stainless steel only £10 !!! but remeber it is M10 x 1.00 not 1.25.

hope something here helps

Si
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reds
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Re: removing pistons from caliper

Post by reds »

thanks for all the input guys - only had rear caliper with me today, tried air with no luck - grease gun worked a treat!

how should i go about cleaning out the grease now though ? run water through the system to clean it or white spirit ????

going to clean up pistons and replace - got some nice silkolene rg pro red grease -would this be suitable- i know gem recommended greasing the pistons, as opposed to the brake fluid suggested in the owners manual
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Re: removing pistons from caliper

Post by masterofinsanity »

i think the white spirit would perish the seals mate, are you replacing seals? cos if you get the old ones out they will probably distort and not go back in.Make sure you don't block any of the fluid passageways with grease!!

I used the red grease on my pistons, helped a great deal i think.
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Re: removing pistons from caliper

Post by cargo »

Use brake cleaner to clean your calipers ................any Auto factors will have it..........................my local pound shop does it too
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reds
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Re: removing pistons from caliper

Post by reds »

finally got the ones from the rear, so seized i had to use mole grips - cradley cant get any new pistons :)

i had rag around them, but the mole grips have burred them, going to get some emery to smoth them down - but i worried these little gauges will cause them to leak - do you think this will be ok (if smoothed down) or do i need to use something to fill them too ??? any suggestions ???
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Re: removing pistons from caliper

Post by mickthemirkin »

Don't tell the Misses :smt003 but an excellent method of cleaning much bike related ephameria is to pop it in the dishwasher on the Hot cycle with two tablets in .... comes out nice and clean. Works a treat for casings, parts, indeed anything that will go in the machine. Be inventive and remove the basket if you have too but it does work rather well.

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Re: removing pistons from caliper

Post by nc73 »

I think wemoto has pistons in stock...
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Re: removing pistons from caliper

Post by reds »

really stuck, grease gun was only think to shift any of them - have had no luck with any other method - anythink left i could try ??? think tapping them out is a bit extreme, but may have to be the way forward :(
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Re: removing pistons from caliper

Post by will#224 »

i've split the calipers and gripped the pistons in the vice before, the pistons didn't look good afterwards though
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Re: removing pistons from caliper

Post by reds »

yeah, reckon i could get them out like that - did with the rear ones, but were really scratched afterwards, used chemical metal to fill + sand them down, as im looking at 25-30 per piston atm !
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Re: removing pistons from caliper

Post by nc73 »

has anyone tried soaking the calipers/pistons in a bath of brake fluid or something similar overnight? i just kept at it, put all pistons back (if they didn't come out at the same time) in until I can loosen the others.
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Re: removing pistons from caliper

Post by reds »

Thanks for all the tips- went to 3 bike shops yesterday with them, they all said the same - hydraulic pressure.

so i disconnected the front brake and now have it running into the caliper - reverse bled it and 2 of the pistons started to push out. However the other two are firmly locked in place - i know baz said something about using a duplo brick ? atm i can only push one of the pistons back in though, the other seems fused in its new position (tried plumbers pliers, and a g clamp to get it back in)

any further tips or tricks for getting them out under hydraulic pressure ?

what happens if i do get them to meet in the middle ? do i then try and pop them out with compressed air ? as atm the only viable option seems to be mole grips, which will bugger hte pistons, and looking into cost its £300 for a new set of calipers, or £40 x 8 for a new set of pistons !!!
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Re: removing pistons from caliper

Post by will#224 »

look on ebay for new calipers same as h model listed under zzr i think, only 200ish with pads
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Re: removing pistons from caliper

Post by RedexRobB »

id place the shaft of a spanner (oooer!) where the disk would normally go. Then use the brake lever/compressed air to push them out. There should be enough there to stop them coming out all the way then.
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