20 replies to this topic

[big dave]

Has anyone done this, I know the bolts are threadlocked in, how did you release them, heat?, a LOT of heat?, impact driver? Tell me how you succeeded.

[Catteeclan]

A lot of heat works for me as it kills/softens the thread lock. You'll need a quality allen key/socket as it'll be a better fit than a lot of the crap that's available.

Some say air guns work well but as those bolts are made of chocolate I daren't try one. 

[leehenty]

heat each bolt with a pencil flame gas torch, wait a bit for the heat to get down to the threadlock,hot air guns are too diffuse and do not work well. Then use a well fitting allen key bit on a T bar.

 Impact drivers will usually round out the socket head or break the 6mm screw off at the root of the thread.

The trick is to turn the screw with the key kept upright in the hole. Normal allen keys add a twisting over motion and are often not successful.

if you do break a bolt in there, I have a proper drilling jig that lines up a drill bit in a sleeve using the centre wheel bearings.

I've done quite a few front brake discs with this method and have only  broken one bolt so far.

 

Edited by leehenty, 08 January 2015 - 05:38 pm.

[ramo]

Dave

 

I just warmed mine with a hot air gun, and they came out easily

 

but its worth cleaning the threads out on the new wheel with a tap before you refit the discs 

[Manx1200]

Think I still have a pencil type mini blowtorch in the garage if you want me to post it to you Dave. Used to use it on bleed nipples without damaging the calipers.it runs off ordinary cig lighter gas.

[big dave]

Thanks Paul, I'm waiting to see if I can get a 17" rim, if I do then I'll swapping the discs over at that time. 

 

I'll let you know.

 

How's things?

[silverback]

invest in some Map Gas and a blow torch from your local plumbing shop, all the plumbers use it, its got a nice fine flame but go easy. when trying to remove things with heat its best to heat 2 - 3 or 4 times before you try to remove the offending  "blighter".....

[leehenty]

Dave

 

I just warmed mine with a hot air gun, and they came out easily

 

but its worth cleaning the threads out on the new wheel with a tap before you refit the discs 

The tap size is M6 x 1.0, a carbon one will do to clean the threads.

[Rallyist]

The tap size is M6 x 1.0, a carbon one will do to clean the threads.

Surely M8 Lee

[ramo]

mr H is correct(I would't even dout him  ), think the rear ones are 8mm

[Manx1200]

All good Dave, Martins having problems at work. Claire goes back to Uni next friday. Hows your brood?

[leehenty]

The front disc screws are an M8 shouldered pin holding the disc into a recess held in with an M6 thread.

All the thread does is hold it in, the real work is done by the M8 shoulder. Silly design really, almost made to shear off.

Rears are straight M8 bolts. This is for a Niner. 850 fronts might be different

[Rallyist]

Glad for clarification Lee 850 is most def 8 mm having broke one in me Mk1

[tr7dan]

Just wondering - replace or re-use the mounting bolts - who does what ? 

 

Dan 

[leehenty]

I would replace as an example of best engineering practice, the originals tend to be a bit soft and round off the hex key hole usually.

I like nice shiny bolts and last time I did mine they were replaced with Probolts finest Titanium alloy offering, but they did relieve me of a considerable amount (£96) of beer tokens.

 

http://www.pro-bolt....ml#.VLBj_iusXn8

Edited by leehenty, 09 January 2015 - 11:20 pm.

[nigel2129]

I had to replace both front discs during the summer and 3 sheered off so instead of purchasing loads of equipment I may never use again I contacted a local engineering workshop and he removed all 3 and recut the threads for £20.
I used OEM replacement bolts with threadlock of course and job done so well happy with that 20 quid spent locally

[Gasman]

Disc bolts look very expensive, where can I buy some reasonably priced ones?

[tr7dan]

http://www.ebay.co.u...=item5d4bc23522

 

 

I just did my rear disc - bolts were £9.99 (genuine Yamaha) and I picked up a brand-new-still-in-the-packet genuine Yam rear disc on Ebay for £58 inc postage - result !

 

Just watch the bolt removal though - I got mine out with a air wrench - easy peasy but I tried first with a T bar... no chance !

 

Dan

 

 

 

[jellypops]

850 are deffo m8 I've just had to drill one out not a nice job but managed to drill out the old bolt and save the threads ☺

[steve27bha]

Disc bolts look very expensive, where can I buy some reasonably priced ones?

 

Sutton have them at £2.95 each new:- https://www.yamahamo...ont brake?uID=0

 

If used is good enough I have eleven - one short of a full set. I bought a box of bolts'n'bits and have extracted the items I needed. You can have the 11 for £10 delivered. The picture looks like 10 (at top left) but I've just checked. The heads/allen sockets are undamaged, the finish the standard dull grey, threadlock remains are on the threads. The stuff appears to be from a 2001 bike.

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