I need new bobbins....

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King Herald
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I need new bobbins....

Postby King Herald » Thu Oct 12, 2017 2:15 pm

Few weeks ago I ch ex my brake bobbins and found them all sieved solid, not a one would move. I freed them off with a nut and bolt through, and brake cleaner, and thought as was well.

Today I noticed a sort of tok tok tok noise when I braked a few times. I stopped, had a good look, found nothing amiss but noticed the discs are very loose. Both sideways and for and aft. I read that ANY radial movement I still is bad.

It doesn’t make the noise every time I brake, but I assume it is the bobbins causing it, being so loose.

I stripped and cleaned the calipers and pads out two weeks ago which stopped an annoying squeal I had, and found nothing amiss anywhere else in the system.

Motorworks sell bobbins, but they are stainless. I read a few old posts in this forum that mentioned originals were aluminium. A set 9 these stainless ones come to the sharp end of 80 quid, so I would like to make sure they are the right thing to get.

Bike is a 97 r1100r
R1100R
Suzuki Bandit 1200

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oldyam
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Re: I need new bobbins....

Postby oldyam » Thu Oct 12, 2017 10:58 pm

I know several folks on here have tried them myself included,

some have had positive results,

I have tried them and found the fit to be too tight giving virtually no lateral movement as if the discs were solid !

I have since gone back to the original BMW ali bobbins and wave washers along with the e clips this returned the dics to no radial movement and a small amount of lateral movement, an expensive exercise overall.

Just my 2 penneth
Nigel
1994 Triumph Trophy in British Racing Green
2007 R 1200 RT Blood Bike Leinster
2000 R 1100 RT in Black ( Sold )
1981 Yamaha XJ650 in Red ( Sold)

King Herald
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Re: I need new bobbins....

Postby King Herald » Thu Oct 12, 2017 11:54 pm

I’m not too sure why the discs need to float actually, as the pads are free to move independently and accommodate any wear.

Where can the original bobbins be sourced?
R1100R
Suzuki Bandit 1200

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oldyam
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Re: I need new bobbins....

Postby oldyam » Fri Oct 13, 2017 12:23 am

Motorworks will supply them as will any BMW dealer, I think the floating part helps in smoothing out any slight warp / runout in the discs, but I take your point about the 4 pot calipers.
Nigel
1994 Triumph Trophy in British Racing Green
2007 R 1200 RT Blood Bike Leinster
2000 R 1100 RT in Black ( Sold )
1981 Yamaha XJ650 in Red ( Sold)

King Herald
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Re: I need new bobbins....

Postby King Herald » Fri Oct 13, 2017 9:24 am

I only see stainless ones in Motorworks, unless I am reading it wrong. Maybe it is the disc they are referring to as stainless?

“BRA 10086 Stainless steel floating front disc mount bobbin circlip and washer 12 reqd per disc”

Part number seems to concur with the bmw part: 34112310086



I could always phones them.... :oops: It’s going to be painful, but not as painful as brake failure. :drunken:
R1100R
Suzuki Bandit 1200

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Jaythro
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Re: I need new bobbins....

Postby Jaythro » Fri Oct 13, 2017 9:50 am

I just fit 6 in each disc I leave the 6 best of the ally ones in to keep the look

Much cheaper and lets face it they were waaaaaaaaaay over engineered with 12 bobbins especially when you look at the later EVO brakes on the 1150 secured by 5 M8 bolts

If a customer wants 12 stainless per side they they get 12 per side but they can be a pain to fit especially at that one that is right over the "spoke" on the 3 spoke wheels
"Put your Ass on a motorcycle and ride with an attitude and the "Grim Reaper" will ride in your shadow!"

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King Herald
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Re: I need new bobbins....

Postby King Herald » Fri Oct 13, 2017 11:00 am

They do look well over-engineered, but I just had a close look and there is maybe a 1/16” radial slop on each disc, so all the existing bobbins are virtually scrap. I just ordered a full set, better safe than sorry. 52,000 miles on these so far, can’t complain.
R1100R
Suzuki Bandit 1200

King Herald
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Re: I need new bobbins....

Postby King Herald » Mon Oct 16, 2017 5:47 pm

My bobbins arrived today, well, 23 did. For,some,reason one packet had been opened and a bobbing removed, then stalled close, Motorworks will be sending it tomorrow.

I got the other 23 fitted with no great dramas. Bit fiddly, getting the rusted old clips off, but no great drama to a handy guy.

One thing to be wary of is overstretching the circlips when fitting them. I accidentally bent one a bit so it was loose, but easy enough to crimp back to shape after I removed it. They are just stainless, not spring steel.

And I have realised they are not actually “floating discs”. To start with, there is no need for them to float, as the pistons are self aligning to allow for wear of pads and disc. I reckon they are bobbin mounted to accommodate thermal expansion without buckling. With a solid disc it will be become wavy as it gets really hot, as there is nowhere for it to move too. The way these ones are it simple expands slightly unhindered. My theory anyway.
R1100R
Suzuki Bandit 1200

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Re: RE: Re: I need new bobbins....

Postby georgeferg » Tue Oct 17, 2017 5:28 pm

I’m not too sure why the discs need to float actually, as the pads are free to move independently and accommodate any wear.

Where can the original bobbins be sourced?
Floating discs allow for heat to dissipate quicker. Amateur racers will drill out fixed buttons and fit floating to maintain consistent braking once heat increases.

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Re: I need new bobbins....

Postby georgeferg » Wed Oct 18, 2017 6:32 pm

So got around to dismantling disks. Put a bolt through the middle and used 2 punches on end of circlip, tapping horizontally so not hammer down on discs. 1st pic shows a reasonable one 2nd and 3rd well worn. Definitely replace all, only £34 for 12 from moto-binsImageImageImageImageImage

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King Herald
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Re: I need new bobbins....

Postby King Herald » Wed Oct 18, 2017 10:00 pm

Yours look as bad as mine were. I got the clips off by slipping a ground down screwdriver into one of the two slots and twisting. It worked on most of them, but some needed a tap with a screwdriver.

I also held the wheel upright in the vice to make it all easier, as I left the discs on the wheel.

Been out for a 30 mile test ride. All seems well, no more noises.
R1100R
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georgeferg
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Re: RE: Re: I need new bobbins....

Postby georgeferg » Thu Oct 19, 2017 1:52 pm

Yours look as bad as mine were. I got the clips off by slipping a ground down screwdriver into one of the two slots and twisting. It worked on most of them, but some needed a tap with a screwdriver.

I also held the wheel upright in the vice to make it all easier, as I left the discs on the wheel.

Been out for a 30 mile test ride. All seems well, no more noises.
For the little extra time to take the discs off I found it a far easier job with them flat on the bench. Plus my circlip wouldn't move with a screwdriver.

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King Herald
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Re: RE: Re: I need new bobbins....

Postby King Herald » Fri Oct 20, 2017 11:54 am

For the little extra time to take the discs off I found it a far easier job with them flat on the bench. Plus my circlip wouldn't move with a screwdriver.

I had planned to do that, but I was afear that I might snap off the screws that hold the discs in place. Apparently the bike stood unloved for a decade in an earlier life, corrosion got its claws into many places. Maybe one day some heat and an impact driver might get them out, but the front discs themselves are in good condition.

Can’t say the same for the the rear one, that will need to come off a time some stage.
R1100R
Suzuki Bandit 1200


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