GSXR brake caliper rebuild

GSXR brake caliper rebuild

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Discussion

JimClark49

Original Poster:

761 posts

150 months

Sunday 26th July 2015
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Hi all,

Was cleaning my Tokico calipers today. Pumped lever, and one troublesome piston's rubber seal came part way out. I ended up opening the entire caliper and will do a full replacement of seals.

Two pistons were rather troublesome in getting out, and I ended up scratching the surface with my mole grip. Picture attached below. Is this damage OK, or will I need new pistons? I am assuming that because the seal sits lower, the scratch shouldn't matter too much and they will not leak.






Also, on recent MOT, I was advised brake pads need changing. Looking at them, it seems they have quite a lot of material left....I am a fast road rider, and use my brakes hard....do you think these need replacing or could I get another 500 - 1000 miles?


Jazoli

9,086 posts

249 months

Sunday 26th July 2015
quotequote all
You will need new pistons, when you fit new pads you are going to have to push the pistons all the way back in, knackering the seals.

Don't use mole grips on pistons, it's a bodge, either use proper piston removal pliers, or remove the pads and put a screwdriver lengthways in the caliper and pump the pistons most of the way out, you can also use a large rawl plug if you've split the calipers which will expand into the piston allowing you to get grips onto the rawlplug and not the piston itself.

HTH smile


Edited by Jazoli on Monday 27th July 14:57

JimClark49

Original Poster:

761 posts

150 months

Monday 27th July 2015
quotequote all
Ok thanks mate.

And how would I put them back in, just push them in with my fingers?

Also, are there any special considerations for bleeding the system of air, or do I just put the caliper back together and bleed as normal?

Jazoli

9,086 posts

249 months

Monday 27th July 2015
quotequote all
Yup they should just push back in, re bleeding the best £15 I spent on a tool was to buy one of these http://pages.ebay.com/link/?nav=item.view&id=2...

But you can just bleed as normal although it'll take a while smile

moanthebairns

17,918 posts

197 months

Monday 27th July 2015
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You've fking destroyed that.

I done a caliper yesterday. It was seized to fk and even with internal pillars was a night mare. Ebay internal caliper pillars. That's what you need

Mines looked like that on the inside of the piston, which doesn't matter one bit as it doesn't come in contact with the dust seal. The outer remains flawless.

Do not even attempt to use that again or you'll fk your new seals.

Don't forget to pump them out as much as you can. Not like me, tt. So much easier when they are half way there. But if you've sticking calipers doesn't always work.

Soaking them in wd-40 is also a good one. Just helps free it that little bit. Pads look fine.

Hooli

32,278 posts

199 months

Monday 27th July 2015
quotequote all
I always use a pad between the pistons to pump them out first. Covers all six & seems just the right size so they don't quite pop out.

As said, you've fked that. It'd still work as the seal sits lower, but it'll kill the dust seal & you'll be rebuilding your callipers all the time. As soon as you find out the price of pistons you'll see why internal pilers are worth it.

moanthebairns

17,918 posts

197 months

Monday 27th July 2015
quotequote all
we better see pictures of the other two...they might be fked as well...

brute force and ignorance are terrible bed fellows with brakes.

sorry, other 6, or other 10, this could get costly....

Edited by moanthebairns on Monday 27th July 14:02

Hooli

32,278 posts

199 months

Monday 27th July 2015
quotequote all
Oh I forgot to answer one bit, the pads look new to me.

Prof Prolapse

16,160 posts

189 months

Monday 27th July 2015
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"If you don't make mistakes you don't make anything", I'm sure I read that somewhere?

I fked my mobile phone trying to fix it on Saturday. Misunderstood how a ribbon clip opened and destroyed the logic board, it's now beyond economic repair. Ironically I fixed the fault first.

But that's the price of amateur DIY. You just try and be humble, learn, and try make sure that over a long enough timeline the cost savings outweigh the cost of your novice mistakes.

If he goes on to rebuild a few more sets of calipers after this he'll still be quids in!

moanthebairns

17,918 posts

197 months

Monday 27th July 2015
quotequote all
"if you don't do anything, you'll never make mistake's"

Prof Prolapse

16,160 posts

189 months

Monday 27th July 2015
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Just testing my point!

JimClark49

Original Poster:

761 posts

150 months

Monday 27th July 2015
quotequote all
Why do we fall? So we can learn to get back up again!

The other pistons are fine, they popped out easy, but these two were stuck and only came a quarter of the way out on pumping the lever.

I have ordered new pistons and a seal set today. I am enjoying working on the calipers and its an easy enough job. The bike is on 28k and calipers were in good nick, so this rebuild should hopefully see another 28k.

Also bought the brake bleeder. If I am right, do I just crack open the caliper bleed nipple and suck through until brake fluid comes out into collecting jar?


Hooli

32,278 posts

199 months

Tuesday 28th July 2015
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28k? just run in!

I changed the pistons in mine at near 100k after damaging them in a similar way.

gwm

2,390 posts

143 months

Tuesday 28th July 2015
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JimClark49 said:
Also bought the brake bleeder. If I am right, do I just crack open the caliper bleed nipple and suck through until brake fluid comes out into collecting jar?
A vacuum bleeder? There will be instructions with it, but I found best way was to connect hose, pump a vacuum and then crack open the bleed nipple.


Jazoli

9,086 posts

249 months

Tuesday 28th July 2015
quotequote all
gwm said:
A vacuum bleeder? There will be instructions with it, but I found best way was to connect hose, pump a vacuum and then crack open the bleed nipple.
That'll work, just keep pumping till clear fluid with no bubbles appears, takes 5 minutes.

Biker's Nemesis

38,534 posts

207 months

Tuesday 28th July 2015
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Jazoli said:
That'll work, just keep pumping till clear fluid with no bubbles appears, takes 5 minutes.
That sound like instructions for having a wk.

kev b

2,708 posts

165 months

Tuesday 28th July 2015
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When you have all the seals removed, clean out the grooves perfectly with something soft enough not to scratch the alloy.

If you don't clean all the furry corrosion and gunge out, your new pistons will soon stick like the old ones, also, use plenty of rubber grease when fitting the seals, this will help assembly and protect from corrosion for a while.

Don't use harsh alloy wheel or brake dust cleaner on your calipers either unless you want to strip them down twice a year.

Finding myself agreeing for once with MTB the piston pliers are well worth owning as well.

Tribal Chestnut

2,997 posts

181 months

Tuesday 28th July 2015
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Don't any of you expert types use a compressor to blow the pistons out?

moanthebairns

17,918 posts

197 months

Tuesday 28th July 2015
quotequote all
Tribal Chestnut said:
Don't any of you expert types use a compressor to blow the pistons out?
No as it barely works at all. You cant pop all 2 or 3 at once.

JimClark49

Original Poster:

761 posts

150 months

Tuesday 28th July 2015
quotequote all
kev b said:
When you have all the seals removed, clean out the grooves perfectly with something soft enough not to scratch the alloy.

If you don't clean all the furry corrosion and gunge out, your new pistons will soon stick like the old ones, also, use plenty of rubber grease when fitting the seals, this will help assembly and protect from corrosion for a while.
Thanks for the tips mate.

I tried to clean grooves best I can with brake cleaner and toothbrush but couldn't get rid of all the corrosion.

Will castrol red rubber grease suffice for the seals? Do i just coat seals and push these in place on the caliper?