Rear Brake Suddenly Not Working. What should I look for?

[Craw]

Hello,

I noticed this morning that my rear brake isn't working at all. The lever feels like it moves freely and the brakes don't engage. I have an 06 Monster Dark. When fully depressed, i can still move my bike back and forth with no problem. The brake was working properly the last time I took the bike out which was about a week ago. Bike hasn't been dropped or crashed.

Could it be a bleeding issue? What are some things I should check out first to figure out what the problem is?

I'm fairly mechanically inclined, however my only experience with hydraulic disc brakes are with my mountain bike.

Thanks for your help!

[wbeck257]

Sounds like you got an air in the lines.

Bleed them. See if that helps.
If it happens again, your master cyl. is going out.

[Howie]

Or caliper.

[ghosthound]

my rear pad wore out at around 5800 miles...

[wbeck257]

If it were pads it wouldn't be sudden...

[Slide Panda]

When in doubt, bleed it.  It's the cheapest and easiest thing to check.  Can't hurt to check the pads while you're mucking about back there.  But a good bleeding will probably sort it.

[fasterblkduc]

Your bike sat for a week? Just pump the lever until you have brake pressure. Then try it.

[DuciD03]

dark 06 - how is the rear caliper mounted?

If its the one mounter below the swingarm; they are difficult to bleed mounted with an air pocket in the caliper; its better to unmount  the caliper and have the bleed screw at the high point; then bleed.  I the first time i discovered this was with a crashed bike and I spent a lot of time & break fluid getting no where ....

Also it is unusual for a problem like that to just show up. What work have you done to the bike?  Check the break lines and calipers any leaks? and any loss of fluid?

I'll bet ya there in lies the problem-o.  Happy bleeding.

[Craw]

dark 06 - how is the rear caliper mounted?

If its the one mounter below the swingarm; they are difficult to bleed mounted with an air pocket in the caliper; its better to unmount  the caliper and have the bleed screw at the high point; then bleed.  I the first time i discovered this was with a crashed bike and I spent a lot of time & break fluid getting no where ....

Also it is unusual for a problem like that to just show up. What work have you done to the bike?  Check the break lines and calipers any leaks? and any loss of fluid?

I'll bet ya there in lies the problem-o.  Happy bleeding.

Brake Caliper is mounted above the swingarm I'll take a look at everything this weekend hopefully.

Thanks!

[Gimpy]

This happened to me on a ride.  It was a hot day, and I was on an old twisty road with lots of gravel. So I was cranking on the rear.  It turns out that I blew my master cylinder.  I looked into rebuilding it buts its cheaper to just replace. 

Try bleeding them before you do anything.  Good luck. 

[somegirl]

I had a similar issue last year and my rear brake just needed bleeding.