No front brake?

[Andrew]

Going to work the other day about 60mph and suddenly the bike started struggling to climb the revs, thought it might have been a fueling issue but then the front wriggled a bit so I pulled off the mway and realised I had no front braking power They were working up to this point as normal and noticed nothing irregular. The lines were changed to Hel braided lines in Jan and new pads were also fitted too. Anyone got any ideas they can throw my way? Had a look over them and saw no leaks or anything so I assume its master cylinder related? Cheers.

[steeeve66]

was the bike struggling because the brakes were binding? and is that the problem with them now? or is the front wheel spinning freely with the brakes just not working?

[Andrew]

I think it was struggling because they suddenly started binding. When I went to slow down there was nothing at all though, there is still nothing and the wheel spins freely. Cheers.

[steeeve66]

the binding could be down to crud clogging the pistons - do you ride in all weathers? clean the callipers often?
the loss of brakes suggests either a prob with the fluid/lines or the piston seals - since the lines were new i'd look at the pistons first (if they'd seized) then the master cylinder/piston.
How long is it since the master cylinder was serviced?

[Fazbaz]

Andrew, get your Faither to pass on my number and give me a call and I'll try and help.

Baz 

[Andrew]

Pistons were cleaned etc mid Jan same time as lines and pads were changed, seemed to move happily. I do ride all weathers, think there was only about 3 days this winter I havent used the bike. I do try and clean the bike regularly and guve the calipers a spray with brake cleaner every now and then. In my ~9000miles of ownership the master cyl hasnt been serviced AFAIK

Baz, he's off tomorrow and is goin to have a footer while i'm at work, he did say earlier that he might give you a wee call

[red98]

if its both front brakes i would look at the master cylinder first

[Major Rant]

If the brakes are binding enough to slow the bike down appreciably then they will get bloody hot, bloody quick!.
All that energy has to go somewhere y'know!
 
As a rough guide, even a slightly binding rear brake will get above boiling point within a mile of leaving home.
and you don't even notice the 'slowing down' effect of that.
 
If they're not getting hot, look for another reason (or maybe even 2 reasons?).

[robby boy]

 
As a rough guide, even a slightly binding rear brake will get above boiling point within a mile of leaving home.
and you don't even notice the 'slowing down' effect of that.
 




If the brake has been hot it is possible for the heat to boil the fluid, a quick bleed would confirm this, (the brake should be good after a bleed) if it is you need to find whats causing the brake to stick and rectify it before you ride it.

[Andrew]

Master cylinder got swapped for a working one off the spare fazer, still nothing.  No surprise the disks were warped so their off now awaiting a new set which should be here  tomorrow. Brakes appear to bleed fine but still no feel in the lever and the pistons no longer push out, thinking maybe one of the lines is dodgey? Will put the OE lines on soon to see if that changes things. Cheers

[red98]

could be that the brake lines have collapsed,ive see this lots of times,they look good from the outside

[richfzs]

on braided lines that are 2 months old, with no signs of leaks?

[Gnasher]

The/a pad/s are/is more than likely locking in the caliper body, they do this by twisting and/or rocking on the pins.
 
Some pad manufactures dont get the dimensions quite right i.e. not long, thick, wide enough.  Which allows slightly more movement within the caliper body over time they actually damaged the working surfaces, tell tail signs are you can see the coating has been removed at each end and/or groves being worn into the caliper body.
 
These groves allow a pad/s to twist and lock causing binding.  The piston/s still do what there meant to and retract this leaves a clearance between the pad/piston next time you pull the level it will feel like there's nothing there and a real lack of power, caused by the piston/s trying bend the pad!     If this is allowed to continue and it only takes a short while, the pad that's locked wears at whatever angle it's locked into which further reduces the power that can be applied, plus the discs can over heat and wrap which magnifies all the above.
 
The angles are small as are the clearances often they can't be seen (if you don't know what your locking for) and all appears as normal check the pad/s if it not worn square/parallel they're locking.  Locking can also be caused by just really dirty calipers and salt and year of poor maintenance. 
           

[dogruff]

Master cylinders very seldom give problems.If your brakes were binding i would have put money on pistons seized or not returning.
The Major is correct.If brakes were binding,all you have to do (at the time) is to touch them quickly with your finger and thumb,or if you have not developed bikers asbestos digits yet,spit on the disc and listen for the sizzle.
Apart from pistons,recheck pads.
 
I take it,that if your brakes "weren't working", the brake lever was solid and would not move towards the handgrip when pulled???