Holey brake pistons and bobbins

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Jmhill
Posts: 7
Joined: Sat Jun 16, 2018 1:10 pm

Holey brake pistons and bobbins

Postby Jmhill » Sat Jun 16, 2018 5:45 pm

Hi,

Really pleased today pulled my R1200S out of the garage where it has been Idle for two years, charged the battery and it started on the first turn.

It needs a bit of work for me the MOT and the front brakes are binding on. I’ve taken the pads out and at least two of the four caliper pistons have rusted holes in the surface that contacts the pad. Is this a problem, a lot of pistons are hollow anyway so wondered if it mattered or not?

Also I have bought new brake pads but I had the choice of pads for fixed bobbins or pads with floating bobbins, I think I got fixed ones they look the same as the ones I had but not sure if the thickness is different. How can I tell which bobbins I have and what is the difference in the pads?

Thanks in advance,

Jon

Humbug
Member
Posts: 637
Joined: Wed Oct 28, 2015 6:06 pm
Location: Nottinghamshire

Re: Holey brake pistons and bobbins

Postby Humbug » Sat Jun 16, 2018 9:31 pm

Pistons should be replaced if they have rusted holes in them, they are weaker than they should be. Fixed bobbins on the 12S, the disc bolts directly to the wheel and does not float. Don't see how it would make a difference to the pads.
My pistons were replaced by Balderstons in Peterborough, about £180 I think for both sides, bleed and replace fluids.
10 KTM RC8

Justcruising
Posts: 76
Joined: Sun Dec 27, 2015 3:33 am
Location: Brisbane, Australia

Re: Holey brake pistons and bobbins

Postby Justcruising » Sun Jun 17, 2018 7:35 am

‘Rusted holes’? Or just some surface pitting? If there were holes I would expect fluid to be leaking out. If it’s just some mild surface pitting you might be able to clean & polish them up ... really depends on the severity of what you’re describing. Photo would help! Otherwise +1 with Humbug on this.
2006 R1200S (Magma-Red/titan-silver) - Michelin PR4s, Akrapovic slip-on silencer, Ohlin suspension, Ilmberger Carbon hugger & Carbon valve-covers, Corbin seat.

2010 R1200R
2004 R1200C Montauk

Humbug
Member
Posts: 637
Joined: Wed Oct 28, 2015 6:06 pm
Location: Nottinghamshire

Re: Holey brake pistons and bobbins

Postby Humbug » Sun Jun 17, 2018 2:18 pm

Pistons have a small hole in the top (not right through) that sometimes make them look worse than they are but I still say change if rusted through. http://www.beemershop.com/Merchant5/mer ... e=BRA38257
10 KTM RC8

jmhill373
Posts: 10
Joined: Fri Jan 04, 2013 10:24 am

Re: Holey brake pistons and bobbins

Postby jmhill373 » Mon Jun 18, 2018 5:27 pm

Hi

Thanks for the advice I’ve bought a good condition used pair for £100 so will keep the originals as spares. Hopefully will be MOT’d and back on the road next week.

Thanks again,

Jon


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