Castlated pistons

4755 Views 21 Replies 10 Participants Last post by ukzx10r, Aug 15, 2016

ukzx10r

Discussion Starter · Aug 11, 2016

Stripped my tokico calipers down to service them and castle top the pistons.
Just thought id share the pic of the tokicos dismantled coz id never seen any pics of it on the internet.
(Probably because most people have a life or are busy looking at porn pics instead lol)
I reccomend people service their brakes regulary as mine were thick with brake dust after just 2000 miles.
They are easy to strip but you really must take extra care with pistons and seals as they cannot be marked in the slightest or they will leak.
Pistons are alloy and would be so easy to mark them.
Seals are not easy to get out without marking.

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SkyDork

· #2 · Aug 11, 2016

And the point of castellated pistons is???? The pistons won't seal good if they're fully retracted and you've got slots for water, dirt, and brake dust to get in behind the pad and hide in the cup area now. I'm betting you're going to say "reduced heat transfer" or something to that effect? I've got a :bs: flag smilie response ready if you do! :ayyy:

+1 for the general brake maintenance comment though!

Lanister

· #3 · Aug 11, 2016

These pistons are designed to reduce brake fade through, yes, reduced heat transfer. Obviously, they're not meant for street use what so ever, rather for race/track application where caliper servicing happens very often. Reactive sells them:

Kawasaki ZX10-R Castellated Front Brake Caliper Pistons

Speaking from experience, stock tokico brakes do fade with heat build-up after about 6-7 hot laps but they aren't exactly unridable either. I run a brake level adjuster to bring the lever out a little and it's no problem. However, if I could get an extra couple of laps without fade from these pistons, I wouldn't mind that at all.

LDH

· #4 · Aug 11, 2016

What pads are you running? Brake fade is all about the heat and some pads run a lot cooler under race conditions than others.

ukzx10r

Discussion Starter · #5 · Aug 11, 2016

Yes they are to dispearce heat. Its what alot of the racers in uk run.
Air flows through and heat can escape from piston unlike standard where heat builds up very high and boils the fluid. Some dont run dust seals and opt for regular servicing.
Mine are only 1.5mm deep so when pressed in fully only 0.5mm of it will be in contact with half of the dust seal.
But as pistons are never in the fully retracted position they are ok to run with seals in.

mr_honez

· #6 · Aug 11, 2016

You said Pr0n lol. :badteeth:

White Fang

· #7 · Aug 11, 2016

That advice is for competent mechanics; would not recommend that the average street guy start tearing into his brakes at 2000 miles or ever, really. Just follow owner's manual recommendations. Maybe keep exterior clean, check fluid and flush every 2 years or per maintenance schedule.

For avid track day guys, yep, better keep an eye on those brakes.

ukzx10r

Discussion Starter · #8 · Aug 12, 2016

What i meant is people should get their brakes serviced on a regular basis.
But with enough information and pictures like above showing whats invloved people may be more inclined to try themselves if they have enough confidence in their mechanical capabilities.
Alot is learnt from information gained from forums. It can enable the average street guy to become capable of servicing their own bike.
We arnt all born with mechanics built in so we have to learn it.

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ukzx10r

Discussion Starter · #9 · Aug 14, 2016

All back together. If you push the pistons fully in they just touch the dust seals but once on the bike the pistons are out a few mm so no probs there. If they were just 1mm deep they wouldnt touch at all but less air gets through.

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Boxtradamus

· #10 · Aug 14, 2016

ukzx10r said:
All back together. If you push the pistons fully in they just touch the dust seals but once on the bike the pistons are out a few mm so no probs there. If they were just 1mm deep they wouldnt touch at all but less air gets through.

I like this! (due to a glitch with this site, I have to post in a thread and LIKE the post within 10 minutes or no Bueno on liking the post later)

Animal11

· #11 · Aug 14, 2016

What tools did you use to take the calipers apart besides allen wrenches? What did you use to remove the seals so as not to scratch them?

ukzx10r

Discussion Starter · #12 · Aug 14, 2016

Animal11 said:
What tools did you use to take the calipers apart besides allen wrenches? What did you use to remove the seals so as not to scratch them?

I used a little hook tool. Its the trickiest part of the whole strip down. You must not scratch a thing. You need a steady hand and just carefully remove them. I did it all fine but im experienced when it comes to jobs like this.
I used a tiny smear of grease on seals to push them back in. I mean small aswel as you dont want grease in your brake fluid.
I used petrol to clean the calipers completely and then blasted all holes out with an airline and then wiped them over with wd40 to preserve them.
These calipers can corrode quite bad if they are not treated with wd40.
I didnt like the quality of the bolts that bolt the calipers together so i fitted stanless ones.

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michael4012

· #13 · Aug 14, 2016

I like the Stainless bolt tip :notworthy:

ukzx10r

Discussion Starter · #14 · Aug 14, 2016 (Edited)

michael4012 said:
I like the Stainless bolt tip :notworthy:

Im sure they wont fail but the standard bolts look very poor quality. Made from what looks like cheap steel. I definately recommend changing them.

White Fang

· #15 · Aug 14, 2016

ukzx10r said:
I used a tiny smear of grease on seals to push them back in.

Seals should be renewed every time. Clean brake fluid of correct type should be used to lubricate the seal and piston/cylinder to keep any chance of contamination to zero.

White Fang

· #16 · Aug 14, 2016

ukzx10r said:
Im sure they wont fail but the standard bolts look very poor quality. Made from what looks like cheap steel. I definately recommend changing them.

If they are OEM they are not cheap. They may not be pretty or shiny but they are strong and beyond minimum specification by a wide margin.

Honda actually requires the replacement of the caliper bolts on some models every time the caliper is removed so the OEMs do take this stuff seriously. (This is a type of bolt that stretches and must be replaced). I have one of those bikes and have laid in a supply for when I change tires. It can be done with only one caliper removed thankfully because the bolts are $4 each.

There are a lot of very cheap but shiny bolts out that so if you replace them for something else be sure of your manufacturer and grade/type.

These are your brakes.

ukzx10r

Discussion Starter · #17 · Aug 14, 2016

White Fang said:
Seals should be renewed every time. Clean brake fluid of correct type should be used to lubricate the seal and piston/cylinder to keep any chance of contamination to zero.

I agree except the seals were as new because they are low milage.
I used smear of grease because i feel it makes the pistons operate smoother. When you push piston in the seals it scrapes grease off because of the interferance fit but you can get a bit inbetween the main seal and dust seal and they operate slightly smoother in my opinion

ukzx10r

Discussion Starter · #18 · Aug 14, 2016

White Fang said:
If they are OEM they are not cheap. They may not be pretty or shiny but they are strong and beyond minimum specification by a wide margin.

Honda actually requires the replacement of the caliper bolts on some models every time the caliper is removed so the OEMs do take this stuff seriously. (This is a type of bolt that stretches and must be replaced). I have one of those bikes and have laid in a supply for when I change tires. It can be done with only one caliper removed thankfully because the bolts are $4 each.

There are a lot of very cheap but shiny bolts out that so if you replace them for something else be sure of your manufacturer and grade/type.

These are your brakes.

Im on about the bolts that hold the two bodies of the caliper together not the main caliper bolts. They look like good bolts on the zx10r

White Fang

· #19 · Aug 14, 2016

ukzx10r said:
I agree except the seals were as new because they are low milage.
I used smear of grease because i feel it makes the pistons operate smoother. When you push piston in the seals it scrapes grease off because of the interferance fit but you can get a bit inbetween the main seal and dust seal and they operate slightly smoother in my opinion

Yes I have reused them as well, I felt I should mention this as seals are terribly expensive and best to renew if in doubt at all.

Agree brakes are VERY important, good to take them seriously.

scout

· #20 · Aug 14, 2016 (Edited)

Very hard for me to wrap my mind around these brakes ever fading. They do catch a tad better when pads are all new but been awhile since I ever changed out all the pads and don't think I've changed all four on either g4's. Can report that pads do react mushy for a few loops with each new front-different-rotor. Pads catch up. Track pros just watch the clock is all. if brakes fad I would suspect parking it somewhere. we have the lap timer, a nice convenience.

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