Bleeding the front brake: lever distance from the bar

[b1k3rdude]

Got a question regarding my bandit 600 (commuter, the thou only comes out on nice days)  -

Recently serviced the front callipers, replaced all the seals and flush the system through with new fluid. The only remaining issue that I cant seem to resolve is the brake lever-to-handle bar distance, in that its coming back too far to the handle before the brakes are applied. But that said when the brake are applied they work well and as expected. Also I have braided hoses fitted.

I have done the cable tie-overnight trick now several times so if there was any air in the system its gotta be bleed out by now.. I even swapped the master cylinder over with a spare one off my fazer 1000 and the same thing is happening.

So does this mean the seals in bandit and Fazer MC's need changing..? as its the only thing left to change I can think of...

[old son]

Have you got standard levers fitted? I had same trouble and it turned out to be the Pazzo levers not bleeding the system propertly.

[mcyoungy]

what mileage is on the bike?


I had similar years ago with high mileage calipers............. the pistons had worn and formed a "waist" that was narrower than the rest of the piston. the pistons would sit at rest in the seals at that "waist". the cure was new pistons all round the front calipers. I'd done all the rest................ seals, fluid, lines, master cylinder

[garysimmo]

dont want to insult your intelligence but have you bled them from the caliper upwards, force fluid up to the res with a syringe, but at the same time slightly squeeze the lever to open the master cylinder, it really does sound like you've got air stuck in the system somewhere.

[t140]

have you tried pushing the pistons into the caliper with a suitable lever, but not too quick or the fluid will spray all over the place, usually works for me.

[b1k3rdude]

Thanks for all the suggestions/questions but I found out what was causing the excess lever movement, it was a combination of the 'spring effect' on the brake seals and half worn pads.

• The spring effect as I understand is - a combination of the pads almost touching the discs and the piston seals grabbing/dragging on the sides of the pistons. This results is the pistons were not allowing me to fully compress/pressurise the system, hence the excess lever play -  or some thing like that.
  
• The pads still had enough meat on them 3-4mm, but apparently bandits unlike Fazers can't deal with worm pads that are still within thier wear limit.
  

[Phil TK]

• The spring effect as I understand is - a combination of the pads almost touching the discs and the piston seals grabbing/dragging on the sides of the pistons. This results is the pistons were not allowing me to fully compress/pressurise the system, hence the excess lever play -  or some thing like that.
  
• The pads still had enough meat on them 3-4mm, but apparently bandits unlike Fazers can't deal with worm pads that are still within thier wear limit.
  

This sounds a bit weird to me. How do you know this effect is actually taking place?
As far as I know Fazers really do not have an issue with part worn pads.
I suspect that you simply havn't bled the brakes successfully and need to try again.
On some machines air bubbles get stuck in the banjo bolt next to the master cylinder. Loosening off the banjo bolt as you pull in the lever then tightening up again before releasing the lever sorts this -if you see brake fluid 'sputter' out when you do this it's a sure sign there was air hiding there.
If you try it, remember to put plenty of rags around nearby paintwork and plastic.

[b1k3rdude]

• This sounds a bit weird to me. How do you know this effect is actually taking place?
  
• As far as I know Fazers really do not have an issue with part worn pads.
  
• I suspect that you simply havn't bled the brakes successfully and need to try again.
  
• On some machines air bubbles get stuck in the banjo bolt next to the master cylinder.
  

Hi Phil

• Popped the pads out the pistons were only moving in and out after 5-10sec of pumping the lever, not progressively further out as normal
  
• I think you misunderstood me, I was saying the same thing as you - fazer done have issue with worn pads, I have even taken mine down to 1mm before changing on occasion
  
• The brakes were successfully bleed and there was no air in the system.
  
• That was the last thing I actually tried, before someone suggested the spring effect and bandits not liking pads that and even half worn.