removing pistons from caliper

Moderator: Moderators

User avatar
reds
L-plate hell
L-plate hell
Posts: 250
Joined: Thu Aug 21, 2008 1:21 am
My Bike: ZXR 400
Location: Stourport On Severn

removing pistons from caliper

Post by reds » Sun May 31, 2009 4:45 pm

any tips ?? manuals saying something about a block of wood ? cant see how this would work ?

also - when trying to bleed my rear brake last night, bleed screw just snapped clean off ! figued will have to drill it out and replace it, but noticed there is also a bleed screw on the back of the caliper - would it be possible to bleed the rear brake using just this one ? have to do it as need new pads in on the back

cheers

reds

cargo
zxr400 oc member
zxr400 oc member
Posts: 3339
Joined: Sat Jan 08, 2005 10:33 am
My Bike: tomos moped
Location: Carrickfergus Northern Ireland

Re: removing pistons from caliper

Post by cargo » Sun May 31, 2009 5:35 pm

You can just use the brake lever to pump the pistons out...............tricky once the first one comes out so you need to use a block of wood to hold back the pistons so they all come out together.......................or just stick an air line on a blow em out................be very carfull as I got a very sore finger doing this :wanker

You should be able to bleed the caliper with just one working nipple but take care that you don't break it too

User avatar
reds
L-plate hell
L-plate hell
Posts: 250
Joined: Thu Aug 21, 2008 1:21 am
My Bike: ZXR 400
Location: Stourport On Severn

Re: removing pistons from caliper

Post by reds » Sun May 31, 2009 6:47 pm

thanks for the info - will try the tyre compressor, as have removed calipers completly !!!

User avatar
andyvanderpandy
zxr400 oc member
zxr400 oc member
Posts: 113
Joined: Sun Dec 09, 2007 10:12 pm
My Bike: zxr400L3

Re: removing pistons from caliper

Post by andyvanderpandy » Sun May 31, 2009 8:21 pm

little g-clamps, rubber sheet for padding, air compresor and selection of fittings, it took me a considerable amount of time to get all 8 out!

User avatar
reds
L-plate hell
L-plate hell
Posts: 250
Joined: Thu Aug 21, 2008 1:21 am
My Bike: ZXR 400
Location: Stourport On Severn

Re: removing pistons from caliper

Post by reds » Mon Jun 01, 2009 11:33 am

nice one, will have a try and see what i can do !

User avatar
masterofinsanity
Site Admin
Site Admin
Posts: 8057
Joined: Thu Aug 29, 2002 12:36 am
My Bike: FZS600
Location: England
Contact:

Re: removing pistons from caliper

Post by masterofinsanity » Mon Jun 01, 2009 11:38 am

or use a Duplo brick :smt002
You do not have the required permissions to view the files attached to this post.
Don't forget people there is more to the zxr400 than this forum... check out www.zxrworld.co.uk also.

User avatar
reds
L-plate hell
L-plate hell
Posts: 250
Joined: Thu Aug 21, 2008 1:21 am
My Bike: ZXR 400
Location: Stourport On Severn

Re: removing pistons from caliper

Post by reds » Mon Jun 01, 2009 9:28 pm

having no luck at all getting them out :(

tried tyre compressor, with rubber seal g clamped in place but wasnt powerful enough (as nothing happened!)

then reassembled the entire front end, and bled it, in order to try and push them out - but i couldnt get them bled at all - was using one of the orange tubes with a slit in it for bleeding, but the oil was simply dripping through it, not spurting out like its supposed to - could the whole issue i have had with soft front brakes be something other than stuck pistons ?

any ideas / tips / tricks ????

will#224
L-plate hell
L-plate hell
Posts: 330
Joined: Sat Aug 09, 2008 11:49 pm
My Bike: L1 racer

Re: removing pistons from caliper

Post by will#224 » Mon Jun 01, 2009 9:45 pm

Having done the same thing your now struggling with i have to suggest a grease gun. Most grease guns have a fitting that will nip on to your bleed nipple. Pump it with grease, it both lubricates and adds pressure to your pistons to push them out. You need to ease all the pistons out at the same time so not to have just one left in.

The compressor with air line sometimes works but the air is dry and there is no lubricant so the pistons often get scratched on the crud thats holding them tight. If you've got a grease gun that is fed with the compressor even better.

If you dont need to reuse the seals etc try soaking them in brake cleaner to remove the crud, if your buying new pistons too split the calipers and use a small vice to bite on the pistons and pull them out.

cargo
zxr400 oc member
zxr400 oc member
Posts: 3339
Joined: Sat Jan 08, 2005 10:33 am
My Bike: tomos moped
Location: Carrickfergus Northern Ireland

Re: removing pistons from caliper

Post by cargo » Mon Jun 01, 2009 10:39 pm

99 times out of 100 my experience with sticking piston in calipers is caused by the crud and corrosion that builds up in the groove the the seals sit in so pushing them out with compressed air doesn't damage them particulary..............I would say I have a proper compressor with 100psi to play with just sticking a tyre compressor on wont be enough and trying to pressureise them isn't going to work you need a short sharp blast of air

User avatar
reds
L-plate hell
L-plate hell
Posts: 250
Joined: Thu Aug 21, 2008 1:21 am
My Bike: ZXR 400
Location: Stourport On Severn

Re: removing pistons from caliper

Post by reds » Mon Jun 01, 2009 11:32 pm

thanks guys

theres compressed air at work i think, so will try tommorow lunch time, see if i can get anywhere

then just have to worry about the fact that i cant bleed the buggers !!!

User avatar
masterofinsanity
Site Admin
Site Admin
Posts: 8057
Joined: Thu Aug 29, 2002 12:36 am
My Bike: FZS600
Location: England
Contact:

Re: removing pistons from caliper

Post by masterofinsanity » Tue Jun 02, 2009 8:56 am

Reds if you wanna take the brake lines/lever off the bike and bring em over i'll give you a hand with em.
Don't forget people there is more to the zxr400 than this forum... check out www.zxrworld.co.uk also.

mickthemirkin
Posts: 25
Joined: Tue Jun 02, 2009 9:21 am
My Bike: ZXR400H2
Location: Leicester, England.

Re: removing pistons from caliper

Post by mickthemirkin » Tue Jun 02, 2009 10:02 am

Do you have braided hoses? Trying to bleed braided hoses in the usual manner is a pain in the proverbial at best and impossble at worst. You can reverse bleed them by using a commercially available pump to fill the system with fluid from the caliper end but obviously there is a cost involved. I did read of someone doing this with a squeezy bottle full of fluid and a pipe to the bleed nipple although I haven't tried it myself so can't vouch for it's efficacy.

As to removing the pistons there have been several good suggestions already but I use a footpump and matress inflator nozzle if they are not too stuck and if they are I have drilled them, tapped a hole, wound in a bolt and pushed it against the back of the caliper to remove really stuck ones with the obvious associated cost of a new piston.

The block of wood idea you mention is to block one set of fluid transfer holes whilst you work on the other ones. Again, use a block of wood with a patch cut from an old inner tube to seal better / prevent damage to the caliper.

Like the grease gun idea, never heard that one before but bet it's a good method and I'll try it myself.

Cheers,

Mick.

User avatar
masterofinsanity
Site Admin
Site Admin
Posts: 8057
Joined: Thu Aug 29, 2002 12:36 am
My Bike: FZS600
Location: England
Contact:

Re: removing pistons from caliper

Post by masterofinsanity » Tue Jun 02, 2009 10:06 am

mickthemirkin wrote:
if they are not too stuck and if they are I have drilled them, tapped a hole,
i don't know why manufacturers never put a tapped hole behind all pistons, would make life soo much easier.
Don't forget people there is more to the zxr400 than this forum... check out www.zxrworld.co.uk also.

User avatar
reds
L-plate hell
L-plate hell
Posts: 250
Joined: Thu Aug 21, 2008 1:21 am
My Bike: ZXR 400
Location: Stourport On Severn

Re: removing pistons from caliper

Post by reds » Tue Jun 02, 2009 3:06 pm

masterofinsanity wrote:Reds if you wanna take the brake lines/lever off the bike and bring em over i'll give you a hand with em.
may have to take you up on that mate, banging my heaad against brick wall atm - will get forks sorted first (waiting on rear pads anyway atm) - you free at any point on sat ?

User avatar
masterofinsanity
Site Admin
Site Admin
Posts: 8057
Joined: Thu Aug 29, 2002 12:36 am
My Bike: FZS600
Location: England
Contact:

Re: removing pistons from caliper

Post by masterofinsanity » Tue Jun 02, 2009 3:28 pm

should be mate.
Don't forget people there is more to the zxr400 than this forum... check out www.zxrworld.co.uk also.

Post Reply