Rear brake lever travels too far and doesnt activate caliper-

[Radar]

Howdy folks,

I'm having an issue with my rear brake system... 05 S4R-

I bled the brakes just a couple of weeks ago, and they did work reasonably well, but I feel like the lever itself has to travel too far to engage the brake.

I adjusted the actuator rod, the one that presses the piston into the master cylinder, as far out as it would let me, but I still think the lever travels to far.

I'm sure I need to bleed the system again, and that's no problem, but I think the lever simply needs a longer actuator rod.

Are there others with similar thoughts? What did you do to fix it?

I was taught that the rod is properly adjusted when there is near zero lash between the rod and the piston in the master cyl...

Also, since the bleeder nipple is on the bottom of the caliper, it may make bleeding that system more difficult. As in.. the caliper must be removed, turned so the bleeder is on top, and bleed away...

Any thoughts?

Thanks-

[ducpainter]

Howdy folks,

I'm having an issue with my rear brake system... 05 S4R-

I bled the brakes just a couple of weeks ago, and they did work reasonably well, but I feel like the lever itself has to travel too far to engage the brake.

I adjusted the actuator rod, the one that presses the piston into the slave cylinder, as far out as it would let me, but I still think the lever travels to far.

I'm sure I need to bleed the system again, and that's no problem, but I think the lever simply needs a longer actuator rod.

Are there others with similar thoughts? What did you do to fix it?

I was taught that the rod is properly adjusted when there is near zero lash between the rod and the piston in the slave cyl...

Also, since the bleeder nipple is on the bottom of the caliper, it may make bleeding that system more difficult. As in.. the caliper must be removed, turned so the bleeder is on top, and bleed away...

Any thoughts?

Thanks-

You need to remove the caliper, place something in between the pads, and turn it upside down to bleed so the nipple is above the master.

You need free play or the brake will lock when properly bled. I believe it's 1.5-2mm before the rod moves the piston.

When you get it bled properly the lever travel will not be excessive.

[Radar]

Perfect-

I suspected as much... I was a bit surprised when I saw the bleeder valve was on the bottom...

Gravity is gravity-

Thanks for the confirmation

[NorDog]

You need to remove the caliper, place something in between the pads, and turn it upside down to bleed so the nipple is above the master.

The nipple has to be above the master cylinder?  Or just above the piston in the caliper itself (slave cylinder?)?

[ducpainter]

The nipple has to be above the master cylinder?  Or just above the piston in the caliper itself (slave cylinder?)?

I always place it above the master. That way all the air in the system can get to the bleeder.

Not sure if it's entirely necessary.

[Cloner]

I always place it above the master. That way all the air in the system can get to the bleeder.

Not sure if it's entirely necessary.

Definitely not necessary, but prudent, nonetheless.  It can save you lots of frustration if there's much air in the system.

[Punx Clever]

Did the brakes on my bike (s2r) a few weeks ago and the rear was a big pain in the ass.  The only way I got it to work was pulling the caliper off and getting the nipple pointing up.  Even then, it took a long damn time to get it properly bled.

[errazor]

Im not an expert, but have some basic hydraulic training. From what i learn, the air is lighter than oil so the bleed nippel must be the higest point in the system and it must be a  rise from the master without any dents that
can create a air lock to the slave. The factory workshop manual recomend removing the caliper and holding it above the master.

[Greg]

Im not an expert, but have some basic hydraulic training. From what i learn, the air is lighter than oil so the bleed nippel must be the higest point in the system and it must be a  rise from the master without any dents that
can create a air lock to the slave. The factory workshop manual recomend removing the caliper and holding it above the master.

Reading the manual is cheating