Worn floating disk buttons

I MOT the bike in March and I got an advisory for rotational play from the button drive rivets on my front discs. Since then Ive started to get uneven braking coming to a stop from 20mph or so downwards. Dont feel anhghing through the lever, just the braking force is on/off/on/off and the bike comes to a stop like a nodding dog.

It feels like a warped disc but I dont see how that would show itself on a floating setup as it should just compensate for it.

I can understand button rivets jammed up with brake dust etc causing that problem, but not loose rivets.

Any ideas??

[Bibio]

Colin stop being a tightass and get a new discs mate. do you really want to be going down the road then go for your brakes in anger for them to suddenly come off the buttons?

[andrewsmith]

Originally Posted by Bibio

Colin stop being a tightass and get a new discs mate. do you really want to be going down the road then go for your brakes in anger for them to suddenly come off the buttons?

This
If they dont seem right replace them

MOT guy said no danger from the disks, showed me a few other bikes in his shop that were the same and said it'd probably go through another couple of MOTs like that at my annual mileage before the play failed the MOT and they had to be replaced. Triumph replacement discs are 5-600 quid, and an aftermarket replacement like EBC are 300. If its a problem I can sort with compressed air and a scoosh of brake cleaner, do I really want to replace the discs??

[Bibio]

how much is your life worth to your family?

i can understand what the MOT inspector is saying but i always take an advisory as 'i can't fail it but i'm recommending you fix it'.

might be worth phoning someone like blackshadow to see if they can replace the buttons if the discs are ok.

Is discs coming off the buttons under braking something that anyone has heard of happening before?

Dont get me wrong, if the discs need replaced I'll replace them. It's not like I cant afford 300 quid, but Im not convinced that the problem is the discs, hence this thread. If they were warped wouldnt I feel it through the lever? Also the bike has only covered 6000 miles. Discs knackered after that mileage?

That said Specialones Sprint ST is in now getting new discs under warranty after 10000 miles, but exactly what us wrong with them Im not sure.

Had the same problem with my front brake , the nodding dog effect. Found play in the disc buttons on both front discs , one was worse than the other. You could move the outer part of the disc slightly, [rotate it - not sideways movement]. I concluded that it could not be right so I looked around on the net for replacement discs - saw some cheap ones and found some poor reports , took the plunge and bought ebc s. Braking problems sorted ! No movement in new discs.

I had this on one of my front discs. The spring/washer on most of the bobbins had shrunk back from the disc, or had rusted through. I was sure that something wasn't good but nothing moved by hand (no more than natural play) but I guess the rust was holding it together enough until that went and the big 'play' became easy to notice. I swapped out the discs as a pair and all was instantly well again. I'm sure that you could get the bobbins replaced rather than the complete disc set-up, so long as they aren't damaged.

if in doubt change them,but ive never heard of disc's coming off the buttons no matter how loose they are,as long as they are just loose and nothing is damaged,ive used disc's on my old gsx600f with about 4mm play on the buttons with out any problems,but they do tend to rattle on rough roads

[yorkie_chris]

Originally Posted by -Ralph-

Is discs coming off the buttons under braking something that anyone has heard of happening before?

Only once with a galfer, the disc actually snapped.