thundercat caliper pistons.

[drbaig]

Brakes were binding so pushed the pistons out, cleaned them and bleed the lines. Didn't make any difference as the bottom two are jammed so still rubbing.

Decided to rebuild the calipers. Now I have a piston out from each caliper by blowing air into it, but now the pressure is lost I cant get the others out. They are properly stuck.

Any solutions.
Thanks
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yzf 600r

[weasley]

Refit the other pistons, clamp them and pump out the others?

Failing that, molegrips and a new piston set.

Or, whilst you're at it, think about upgrading to the later R6 calipers which have no cross-caliper link pipe, thus are easier to bleed?
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Yamaha XJ600 | Yamaha YZF600R Thundercat | KTM 990 SMT | BMW F900XR TE

[P.addy]

[weasley]

The Cat calipers have a small external pipe linking one side of the caliper to the other. It is said that this is the cause for many failed bleeding attempts. Later blue spots are redesigned with an integral fluid transfer link. Fit is the same though.
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Yamaha XJ600 | Yamaha YZF600R Thundercat | KTM 990 SMT | BMW F900XR TE

[P.addy]

Oooh, didn't realise they were different! Never seen one without the pipes

[drbaig]

I was able to bleed the calipers fine. Just can't seem to get the pistons out. Haynes suggests doing one side at a time but the bottom ones are jammed stuck plus I don't want to buy new pistons.

Any suggestions other than destroying current pistons trying to get them out.
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yzf 600r

[Robby]

Clamp the other pistons and leave the jammed ones free, pump the brake until they move.

[temeluchus]

all of the first generation fazers and XJR1300 calipers will also fit as they are the same as the r6/1. probably tdm 900 as well?
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Some shite cruiser. Now with guns and FREEDOM!

[Fizzer Thou]

By clamping the freely moving pistons and concentrating on the seized one then the procedure should be easier.There should be no need to use molegrips as the pistons should move out with sufficient hydraulic pressure.I have a spare set of handlebars and an old but good master cylinder for doing this on the workbench

https://i666.photobucket.com/albums/vv23/WiNot_Rhencullen/Workshop/Picture383.jpg

Once the seized piston is out,clean the seals and grooves and reinstall.I install only the distortion seal,then once all are clean I then reinstall the dust seals

https://i666.photobucket.com/albums/vv23/WiNot_Rhencullen/Workshop/Picture384.jpg

Use red seal grease for reassembly
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Just talk bikes.What else is there?

Always have a 'Plan B'

[totalllama82]

Had a nightmare bleeding mine. Squishy as. I ended up reverse bleeding them with a syringe. Still not 100% but better.

I rebuilt the callipers, MC new lines... everything in an attempt to get something better from them.

Now ended up with the dreaded 6pot Tokico's on my ZX9.
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Gone: Haotian HT125-8 / Yamaha YZF 600R Thundercat / Kawasaki ZX9R C2
Current: Kawasaki ZZR 1400 A7F

[mcyoungy66]

a piece of wood in between the 2 free pistons is as good as clamping them, then use air to pump out the others.

[weasley]

That'll work if the two free pistons are opposite each other.
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Yamaha XJ600 | Yamaha YZF600R Thundercat | KTM 990 SMT | BMW F900XR TE

[Islander]

[drbaig]

I am going to try taking the dust seals out of the two top pistons I have already managed to get out by pumping air through the union bolt hole.

Then put the top two pistons back in and clamp three to get one of the bottom one out. Then remove the dust seals from that one put it back in and do the same thing for the final one.

Hopefully one seal shouldn't create too much of a problem, just prying them out with fingers. Or clean two at a time, fit them back and try two at the bottom. Or do them one by one cleaning and replacing the seals.

Lets see how it goes tomorrow.

Plus the speedo cable has snapped, I have heard that it can be changed by just taking the screen off with the top black plastic inside fairing bits and the gauge cluster. But It is brakes first. One problem at a time.
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yzf 600r

[StevenF]

[drbaig]

I actually forgot to ask. Is there a specific way the seals go in (upside and downside). Like are they perfectly Square or is there a slight lip that creates the seal with the caliper and the piston. I've already done one caliper. Do I need to go back
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yzf 600r

[drbaig]

I actually forgot to ask. Is there a specific way the seals go in (upside and downside). Like are they perfectly Square or is there a slight lip that creates the seal with the caliper and the piston. I've already done one caliper. Do I need to go back
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yzf 600r

[Fizzer Thou]

I have only heard of Suzuki piston seals having a certain way that they must go in.Of all of the calipers that I have serviced I have never seen this on any seals.

If you do not have any red seal grease you can always use fresh brake fluid.

DoT4 brake fluid at Asda is £4 for 500ml

If when bleeding the brakes, remove the caliper from its mounting and lift it as high as you can get it and hold it there for a few minutes.Any air in the lines will go to the caliper,which you should then be able to bleed successfully.
____________________
Just talk bikes.What else is there?

Always have a 'Plan B'

[drbaig]

I cut the old inner seal to check if they were square which they were so went ahead and did the rest.

Managed to clean and fit new seals. One by one, what a pain. Wedged the pliers between two opposite each other and clamped one whilst pumping air in the union bole hole.

They needed a proper good cleaning. The groves were covered in dried salt, brake dust and god knows what else behind the dust seals for the bottom pistons. Just because of the oily mess I'd rather pay someone to do forks and brakes.

Have bleed the system but there were millions of tiny bubbles in the end. So now I have tied the brake lever to the bar and left it. Will bleed again after those tiny ones have got together to make big ones. Job should be done then I guess.

Dot4 is even cheaper on eurocarparts. 500 for 2.40 i think.
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yzf 600r