Brake Seals

Technical discussions and mechanical advice. Need help with your bike?

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Brake Seals

Postby nato69er » Fri Aug 17, 2012 8:45 pm

Emergency call! Was changing the front pads on the r1, got them in and even cleaned the pistons, just to find that one of the seals is peeing brake fluid out.
Not necessarily a problem apart from I was hoping to ride to a test ride a speed triple on it, so does anyone know where I could get seals from at short notice?
Oh and how can I get the piston out?

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Postby Simple » Fri Aug 17, 2012 9:14 pm

On a friday at 7.45pm... think you're fooked.

Alf Englands might have the part on the shelf?
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Postby nato69er » Fri Aug 17, 2012 9:20 pm

Thanks Sarah good shout. It's ok if I can pick them up in the morning. Any tips on piston removal?

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Postby Simple » Fri Aug 17, 2012 10:35 pm

Not had fluid pish out past a seal before, had is seep out, in which case i could still pump the piston out.

Perhaps a potato.. I know alex likes using those.. :roll:

sorry
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Postby Willopotomas » Sat Aug 18, 2012 12:34 am

Hold the other piston(s) in with a g-clamp and use the hydraulic pressure to push the offending one out.
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Postby evoboy » Sat Aug 18, 2012 1:00 am

Those calipers are a bitch.

You have to make sure all the other pistons are fully home and locked in place somehow.

Then if itll push out via the lever, then great, if it wont cos of the leak, then youll need to take it off and try putting a compressor on it to blow the piston out.

Have fun! :lol:

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Postby D-Rider » Sat Aug 18, 2012 9:03 pm

Got mine out from callipers that were removed from the bike by taking a suitably sized socket, wrapping it iy electrical insulation tape until it was a tight fit, shoved this in the cavity in the piston and with a judicial amount of twisting and pulling (the twisting being very important) I got them out.

Of course mine were Brembos and Brembo won't sell seals (except for race callipers and KTM) so sourcing new seals was more of a challenge.
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Postby Simple » Sat Aug 18, 2012 11:58 pm

Willopotomas wrote:Hold the other piston(s) in with a g-clamp and use the hydraulic pressure to push the offending one out.


That's the problem though isn't it? It's spurting brake fluid past, so rather than building pressure it's releasing it.


D-rider's idea might work if the brake fluid is spurting out...
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Postby Willopotomas » Sun Aug 19, 2012 12:57 pm

Was also said that while he was changing pads he noticed the fluid. If it was that bad, the reservoir would've emptied long before the issue was stumbled upon. The spattering of brake fluid all over the bike would've also been obvious.. That stuff gets everywhere.

Of course this is all guess work as one man's idea of something 'peeing out' may be different to another's, and I've not seen the aforementioned brake calliper. Pistons can be cleaned without taking them out of the body.
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Postby evoboy » Sun Aug 19, 2012 2:17 pm

but to change the leaking seal, you must remove the piston from the pot that is leaking. You cannot split these calipers either which makes the job even more awkward.

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Postby banner001 » Sun Aug 19, 2012 9:39 pm

i always pumped mine the majority of the way out then wrapped the end of some mole grips in cotton gauze and used them to pull the pistons out.
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Postby nato69er » Mon Aug 20, 2012 8:25 am

Ok sorted some seals Saturday (thanks Simps) £25 for two pistons worth! Then scurried back home to extract the piston. Had to use a foot pump and pipe work to get enough pressure but it worked.
Swapped the seals although the originals looked fine. Got the whole lot back together and tried bleeding the caliper only for more fluid to come out. Tried tracing it and it looked like the bleed nipple wasn't sealing. :?
Cut to an hour later after faffing with all kinds of bleeding methods I final thought about the one way bleed kit I was using. Took the valve out and used a single pipe in some fluid and guess what... it bled straight away and with no fluid anywhere.

So £25 and 4 hours spent just to find that it was the cheap bleeding valve that was making the mess. PITA! :roll:

Thanks for the help guys. :wink:

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Brake Seals

Postby PeterGancy » Sun Sep 10, 2017 8:44 pm

Thanks for the help.
I have toyed with the idea of changing the seals and the brake line, it is rubber and looks like new, but im out of work at the min and just trying to keep it ticking over.
Jem I have tried that too
On closer inspection it would seem that the free moving pistons have now got kinked in the caliper so fluid has been by-passing them and going out the nipple, off i go to war again
Cheers

Mark

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