replacing front brake discs

[sc0ttie]

it easy enough to do at home? Any tips?

[darrsi]

Firstly you need to pray that the bolts don't round off, as they tend to be made of marshmallows.
Make sure you thoroughly clean the flat face of the wheel that the disc sits on, including any crud that's built up around the inner circle, it basically needs to be spotless to avoid any unevenness.
Use a torque wrench to do the bolts back up in a criss cross fashion.
Don't use copper grease on the bolts either, I would either dip them in oil or use a tiny dot of Loctite, so that torque settings stay true.

[Punkstig]

Heat, lots and lots of heat!

[Jules-C]

Bolts will either round off or the heads will shear off!  Heating them may get them out easier.  Buy a set of stainless bolts to replace them

[sc0ttie]

Ok thanks for these tips. Am I going to need a front paddock stand to hold the front end up when i take the wheel off?

[limax2]

Paddock stand not needed. Just support the front with jack and wood or some such under the frame or even the exhaust pipes.

[joebloggs]

Struggled with my rear, ended up with molegrips on the outside of the bolt and an allen key in a socket, you'll need help steadying the wheel but they came out with no heat etc.

+1 on the stainless replacements.

[darrsi]

Struggled with my rear, ended up with molegrips on the outside of the bolt and an allen key in a socket, you'll need help steadying the wheel but they came out with no heat etc.

+1 on the stainless replacements.

He's on about the front, they're not half as bad as the rear one due to no heat transfer because of the floating discs.

[unfazed]

Struggled with my rear, ended up with molegrips on the outside of the bolt and an allen key in a socket, you'll need help steadying the wheel but they came out with no heat etc.

+1 on the stainless replacements.

I presume you are speaking about the bike :lol

[joebloggs]

[quote author=joebloggs link=topic=18968.msg219662#msg219662 date=1450820292]
Struggled with my rear, ended up with molegrips on the outside of the bolt and an allen key in a socket, you'll need help steadying the wheel but they came out with no heat etc.

+1 on the stainless replacements.

He's on about the front, they're not half as bad as the rear one due to no heat transfer because of the floating discs.
[/quote]

I think it was the amount of threadlock on the bolts that made them so difficult to remove, smothered in it.

Either way, they would probably rounded off without the extra torque applied by the grips

[darrsi]

[quote author=darrsi link=topic=18968.msg219666#msg219666 date=1450823008]
[quote author=joebloggs link=topic=18968.msg219662#msg219662 date=1450820292]
Struggled with my rear, ended up with molegrips on the outside of the bolt and an allen key in a socket, you'll need help steadying the wheel but they came out with no heat etc.

+1 on the stainless replacements.

He's on about the front, they're not half as bad as the rear one due to no heat transfer because of the floating discs.
[/quote]

I think it was the amount of threadlock on the bolts that made them so difficult to remove, smothered in it.

Either way, they would probably rounded off without the extra torque applied by the grips
[/quote]

That certainly would make things even more difficult, but heat transfer from the rear disc goes through the bolts and tends to fuse them to the wheel over time.
I had a nightmare with one of mine a few years back, and tried everything including plenty of heat, but only one bolt budged half way then snapped on me, so rather than ponce about I bought another used wheel and got the tyre changed as I needed the bike back on the road asap due to it being my only transport.

[Gnasher]

That certainly would make things even more difficult, but heat transfer from the rear disc goes through the bolts and tends to fuse them to the wheel over time.
I had a nightmare with one of mine a few years back, and tried everything including plenty of heat, but only one bolt budged half way then snapped on me, so rather than ponce about I bought another used wheel and got the tyre changed as I needed the bike back on the road asap due to it being my only transport.

As with most things it's not always that simple, as there's heat and then there's heat!  The issue is the amount of thread lock applied to the bolts this is a very hit and miss, some have hardly any, a lot have way too much![size=1em] Most use a butane blow lamp type that screw in to a can, they don't provide enough heat to tackle the stubborn over coated bolts.  [/size]The 2 ways I remove stubborn bolts is to use acetylene, or for when owners have tried all the normal stuff and rounded the bolt head and the hex key, I cut a quality hex key down a weld it into what's left of the bolt.  The heat from both methods quickly penetrates down the bolt melting the thread lock, butane can't deliver enough heat, the heat it does produce ends up being dissipated through the disc/wheel which can bugger the finish on both even distort the disc carrier, but do absolutely nothing to the thread lock.                 

[joebloggs]

darrsi. See I told you it was the threadlock Na...Na Na Naa Na  :b

[Deefer666]

I heat the living fuck out them with a blow torch then attack them with an impact driver and a lump hammer. Most to the time they will come out that way....the rear discs are another story.

Most of the ones I have done it seems that the technician that Yamaha use to assemble the front end had a threadlock fetish!

[darrsi]

Well at least it's good to know that even pro's have issues getting the damn things off.  mash

I bought myself a set of replacements bolts before the job last time which was a really good move as I did have to replace two of them due to rounding the heads off.
What should in theory be such a straightforward swap of discs can turn into an absolute nightmare.  :groan

[unfazed]

darrsi. See I told you it was the threadlock Na...Na Na Naa Na  :b

They are Threadlocked for a good reason, you don't want those bolts loosening.

A bit of heat to the wheel around the bolt area usually softens the thread lock and a Torx hammered into the Allen head works wonders :thumbup

[joebloggs]

[quote author=joebloggs link=topic=18968.msg219710#msg219710 date=1450871125]
darrsi. See I told you it was the threadlock Na...Na Na Naa Na  :b

They are Threadlocked for a good reason, you don't want those bolts loosening.

A bit of heat to the wheel around the bolt area usually softens the thread lock and a Torx hammered into the Allen head works wonders :thumbup
[/quote]

Maybe I've been lucky or maybe its because I'm always pulling things apart every few mins but I've never used threadlock on any nut or bolt and (touch wood) I've never had a bolt come loose

Not recommending not using it, but I prefer copperslip to prevent corrosion from welding the bolt in place and a good swing on the spanner to make sure the only time it comes undone is when I want it to

[darrsi]

I used copper grease on everything for years but then completely knackered a thread on my rear calliper, resulting in me getting another one.
Even though I used a torque wrench, copper grease completely throws settings out of the window.
I tighten most things by feel now, but I personally think things like disc bolts should be torqued evenly.

[sc0ttie]

Am buying a set of front discs on ebay, my front tyre needs replacing so I was wondering, since i will need to get a bike garage to fit the tyre for me, would it cost a lot if I got the garage to fit my discs for me whilst the wheel is off? any ideas on price for that sort of job and fitting the tyre as well?

[Paulfzs]

tyres usually £10 or so to change with the wheel off.


discs maybe £10-£30 depends how easy they come off