Replacing Rear brake disc

[darrsi]

Too late now.  The 6.8mm got the remains of the bolt out and I cleaned up the threads with a tap.  All looked good until I tried to torque them and the thread gave way.

I'll have a look at threaded inserts next, but I'll have to get another wheel, as I need to be back on the road next week.

Damn, what a nuisance!  :'(

[daviee]

wurth time serts job done they are about the best about only take a couple of hours to do them all

[unfazed]

:agree :thumbup

[Disorderlypunk]

just wondering if anyone has had success using a manual impact driver on these
i.e the one you hit with a hammer not the 'Buzz gun'
as it is a hammer thump and a turn in one where a buzz gun is more just rotational whacks?
just a thought

[darrsi]

just wondering if anyone has had success using a manual impact driver on these
i.e the one you hit with a hammer not the 'Buzz gun'
as it is a hammer thump and a turn in one where a buzz gun is more just rotational whacks?
just a thought

That's what I was initially using for my rear disc on Saturday. Would've worked a lot easier after a bit of heat, even though 5 out of 6 worked straight off.
Was worried a little bit though because it was so cold outside I was scared of cracking the wheel hub.

[Disorderlypunk]

its another one of those tools i have been meaning to buy for ages but when i need one i find another way (cant wait for delivery)
and then i forget about buying one untill i next need one and the cycle repeats itself
getting 5 out of six easily out definatly says its worth having one for that job though considering the problems others are having

[darrsi]

its another one of those tools i have been meaning to buy for ages but when i need one i find another way (cant wait for delivery)
and then i forget about buying one untill i next need one and the cycle repeats itself
getting 5 out of six easily out definatly says its worth having one for that job though considering the problems others are having

I've only put a small dot of Loctite around 4 threads from the top of the head this time which should spread when tightening to cover them all, but if I heat them next time and use the impact driver I won't accept anything but instant success on all 6 bolts.  :lol

[Trebus]

Impact drivers can definitely get you out of here shit. The trick in my experience is to use it first, once any button head Allen bolt starts to get rounded they are always a bit of a game. Sometime you can knock a Torx bit in instead if it rounds.

Never done the Fazer disc bolts but had a game on other bikes over the years. Luckily no defeats though ?

[darrsi]

Impact drivers can definitely get you out of here shit. The trick in my experience is to use it first, once any button head Allen bolt starts to get rounded they are always a bit of a game. Sometime you can knock a Torx bit in instead if it rounds.

Never done the Fazer disc bolts but had a game on other bikes over the years. Luckily no defeats though ?

I just don't see why they have to use allen head bolts made from marshmallows though.
Why not use hex bolt heads instead, then when removal time comes just use a 6 sided socket, which impact sockets are anyway, and it should make life much less stressful.

[celticbiker]

As an engineer I would agree, practical functional and future proof but button heads are considered more aesthetically pleasing.
If practicality was a consideration everything would be Stainless and bike would be a lot more expensive.
It goes together quick, looks pretty and the components are cheap. One it's our of warranty it's your problem.

[Jules-C]

Stainless steel is a lot cheaper than it used to be and the additional cost these days would be only 1p or 2p a bolt.  Additional cost for a new bike would be around £10.

[tommyardin]

Stainless Steel is a great product for sure, but alas it has it's own set of problems to, I sail and all the metal fittings on the yacht are stainless or brass because of salt water corrosion.
Turnbuckles on mast rigging on our boat are stainless steel and ideally should be taken off every 6 months or so to help stop 'Galling' (Please see link below)


The magic Red Rubber Grease is the yachtsman's friend, the other friend is patience, don't be in a hurry, now this might sound silly but bear with me, spinning a nut fast down a stainless steel thread can generate incredibly high temperatures just at the apex points of both the thread, this high temperature is lost very quickly but is instantly regenerated by the next revolution of the nut or fastener and on the process goes eventually welding the nut to the bolt (or Turnbuckles in my case).


On the boat I use waterproof grease on the thread (Red Rubber) and slowly tighten the parts up (don't spin the nut down the thread at high speed)


Now you might be thinking tommy is yet again talking poo, the same process can take place on other metals aluminium being one of them, a form of Galling is often what will strip the threads out of your rear wheel hub when changing your rear disc.
Take a look at the link it makes good reading, that exact link changed my understanding on contact friction and galling weld.
[size=1em]Now I wonder why I am so opposed to LocTite on threads that go into alloy, as if they did not have enough struggles with out that being added to the frame.    [/size]




    https://www.fastenal.com/content/feds/pd...alling.pdf

[Jamieg285]

That's an interesting read.  It makes me think that perhaps I should ditch the air wratchet (not impact driver) when rebuilding and stick to hand tools.

[darrsi]

As an engineer I would agree, practical functional and future proof but button heads are considered more aesthetically pleasing.
If practicality was a consideration everything would be Stainless and bike would be a lot more expensive.
It goes together quick, looks pretty and the components are cheap. One it's our of warranty it's your problem.

Disc i just put on has a circular area machined into the disc where the allen head bolt heads sit perfectly inside them, so a hex head bolt wouldn’t work with this particular one, but i’d imagine most other discs are just a flat sheet of metal so it would work okay.
I’ll definitely do some research next time and see what’s about.

[celticdog]

[quote author=celticbiker link=topic=23511.msg271802#msg271802 date=1512026473]
As an engineer I would agree, practical functional and future proof but button heads are considered more aesthetically pleasing.
If practicality was a consideration everything would be Stainless and bike would be a lot more expensive.
It goes together quick, looks pretty and the components are cheap. One it's our of warranty it's your problem.

Disc i just put on has a circular area machined into the disc where the allen head bolt heads sit perfectly inside them, so a hex head bolt wouldn’t work with this particular one, but i’d imagine most other discs are just a flat sheet of metal so it would work okay.
I’ll definitely do some research next time and see what’s about.
[/quote]


I had the same darrsi, but unfortunately the countersunk recess was smaller than the size of the fazer button head bolts. I had to turn the heads down on the bolts to 15 mm, an easy fix.

[Jamieg285]

wurth time serts job done they are about the best about only take a couple of hours to do them all

I looked at those, then went and bought a cheaper alternative (Silverline threaded inserts from Amazon).

Was a piece of cake to fit and has done the job really well.  I was able to drill, tap, fit the insert, fit the disc and then remove and replace the wheel on the bike in about 45mins. 

[Disorderlypunk]

That's an interesting read.  It makes me think that perhaps I should ditch the air wratchet (not impact driver) when rebuilding and stick to hand tools.

best thing i have read in ages - when dismantling i tend to use a buzz gun for most stuff as it is faster but when reassembling i might use a buzz to get things 95% done  (cam covers mainly) then i switch to hand tools just so i can feel everythings tightness then pull out the trusty torque wrench