Disc bolts.... and Calipers

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DavShill
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Disc bolts.... and Calipers

#1 Post by DavShill » Thu Jan 10, 2019 2:02 pm

The winter refurb and essential jobs are underway. Front calipers have been split and fitted with new seals (thanks KTM) and they already have nice shiny titanium or SS bolts. This now makes the disc bolts look shabby.

So Ive seen ss bolts for the rear disc on fleebay but i think I'm correct in thinking that these will not register on the speedo sensor. I presume its magnetic saucery. Correct?

Has anyone changed them for anything other than OEM bolts.

No problem with the front disc bolts, they can just be replaces with shiny ones of the same size and thread pitch. Correct?
Last edited by DavShill on Fri Feb 01, 2019 2:34 pm, edited 1 time in total.

fatboy
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#2 Post by fatboy » Thu Jan 10, 2019 7:15 pm

IIRC,you need one ferrous bolt for the sensor to work ?
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mangocrazy
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#3 Post by mangocrazy » Thu Jan 10, 2019 7:46 pm

For the front, bolts of the same thread pitch (M8 x 1.25) are needed. You could probably get away with stainless, but I've played safe and used steel. For the rear disc, they do need to be steel. Not sure if you could get away with just one steel, or whether that might only indicate a fraction of the true speed...

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#4 Post by blinkey501 » Mon Jan 14, 2019 5:52 am

I have stainless on the front, and mild steel on the rear.
Tolerance will be our undoing.

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#5 Post by D-Rider » Mon Jan 14, 2019 2:49 pm

Yep Steel ones in the rear .... and that means all of them
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DavShill
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#6 Post by DavShill » Mon Jan 21, 2019 1:04 pm

yes that's what I thought. Just cleaned up the old rear bolts and they look ok now.

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DavShill
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#7 Post by DavShill » Fri Feb 01, 2019 2:33 pm

Front calipers all rebuilt and shiny and reinstalled. Lovely.
Rear caliper bleed bolt is seized and I've rounded the f****ng shoulders off :smt013
Also the bolts holding the two parts of the caliper together are seized and I've rounded the allen bolts too :smt013 :smt013.

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Greg
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#8 Post by Greg » Fri Feb 01, 2019 9:20 pm

Dav

The bleed nipple will come out relatively easily if you give it enough heat and use a 6 sided socket. MAPP is good!

The caliper bolts - if they're hex sockets then bang in a torx bit - but you'll need to give it some welly - and again as much heat as you can ...
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DavShill
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#9 Post by DavShill » Sun Feb 03, 2019 3:15 pm

Cheers Greg. that's the plan tomorrow. My pal work at BAE systems in Brough and he will apply the necessary techniques for me.

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Greg
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#10 Post by Greg » Sun Feb 03, 2019 5:49 pm

Grand - he's sure to have an approved BFH then ..

Seriously though some of those aviation engineering types have access to tools and skills that we mew mortals can only dream of.. My uncle worked at Dowty in Gloucester and rebuilt his old '33 Rudge Rapid, but with loads of bits made from scratch out of all kinds of unobtanium .. the only ever Rudge to have had a NikaSil plated cylinder for example.

After he died a few years ago his fucking idiot son sold it, along with a '29 BSA 600 Sloper, both for around £1500 apiece as I recall.. Despite all his family knowing of my passion for the bikes - neither of his sons did - they didn't even give me first refusal... Not spoken to the twats since...

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#11 Post by fatboy » Sun Feb 03, 2019 7:38 pm

Hey Greg,
You know how the grading system goes, Automotive, Marine,Aviation.....
So a BFH Aviation grade is good stuff yeah ?
By the way, should the opportunity arise to push said relatives under a passing train.....
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#12 Post by DavShill » Wed Feb 06, 2019 7:28 pm

Yep - he sorted it in about 5 mins. No heat just proper tools :smt001

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#13 Post by mangocrazy » Wed Feb 06, 2019 10:39 pm

I remember trying to rush a job (stripping the front calipers on the VFR) and not using the correct tool for the job. Long story short, I wound up having to drill out one of the Allen bolts that hold the caliper halves together due to rounding off the internal hex of the bolt. That taught me a lesson...

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