Pistons stuck in Calliper.... any tricks?

[wr6133]

Tokico callipers off a ZZR.

No idea how long they have been stuck in there the callipers came with a big box of parts. As new pistons appear to be £20 each on eBay I'm keen to not resort to drilling them out. For the price of new pistons I could get better callipers (2nd hand).

I don't have a grease gun or airline.

So far I have tried

Hooking them up to a tyre inflator compressor thing that claims to make 250psi (it cost a tenner so probably makes a lot less).

Boiling them

Freezing them

I'm willing to try any crack pot ideas that have a vague chance of working!

Thanks in advance for any help

[sickpup]

Connect them one at a time to a master cylinder and pump the pistons out.

[Azonicben]

I got a set of these to do mine, amazing how easy the proper "cheap" tool makes the job.

https://www.ebay.co.uk/itm/like/191046467082?limghlpsr=true&hlpv=2&ops=true&viphx=1&hlpht=true&lpid=108&device=m&adtype=pla&crdt=0&ff3=1&ff11=ICEP3.0.0-L&ff12=67&ff13=80&ff14=108
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Cbt-23/09/07.....Theory-16/09/08.....Das passed 10/10/08.....
Current bike- GsxR750 K4. Broken: Cbr400rr (Nc29) Sold: Hyosung GT125R

[lihp]

Grease gun on the bleed nipple.

Clean them out properly afterwards.
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covent.gardens: lihp is my most favourite member ever

[davebike]

Use the pliers sujested above the rotate the pistons if they will not rotate The callipers will need to be connected to a master cylinder the system filled with fluid a piece of Steel the thickness of a disk placed as a disk wood be to stop any piston coming right out and the master cylinder pumped This should move all the pistons

The groves the seals sit in will have corrosion in them and will need cleaning and new seals (use rubber or silicon grease to fit the seals not brake fluid ) for a longer life and less corrosion behind
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Dave
NC750Xdct + others at work !
davebike1@gmail.com

[wr6133]

[Islander]

[bikenut]

tricks..........

with a single piston caliper stripped to it bare hydraulic element ( slide caliper bolted together ) ( seized pad pins? with new ones available, saw in half the pins so the hydraulic element can be tackled on its own, the cut pins can be tackled separately, some heat and turn, water can help as a release/washing agent as the corrosion is water based....) and the hydraulics still connected, place the hydraulic element in a bucket of very hot water ( expands the alloy quicker than the steel ( plastic ) piston ) and pump away........let the piston come out as far as you dare but not completely so you still have effective hydraulics.........use g clamp and protection and push the piston back in. Repeat till the piston is "exercised" and freeish, then pump out all the way.........

this method works...........you will see why the piston is stuck, corroded and pitted, and the corroded alloy "land" tween hydraulic seal and the outside world/gaiter.

use red rubber grease when reassembling.

for multi pistons. multi sided, just deal with one piston at a time till free ( but don't pop it out yet ) by clamping the other pistons with protection and g clamps etc.

when all are free, pop them all out.

special pliers can be made to grip the inside piston void ( the big hole in some pistons on the outside ) , rotate and pull at the same time to get them out when they are FREE'd off.

pic of your caliper would help.
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nuts about bikes

[sidewinder]

Took mine to my local dealer.they blew them out with a high pressure grease gun thing.cost me £5.

[sickpup]

You could always buy a proper piston puller kit like this one. Much better than the pliers type, it actually works.