Rear brakes disappeared

[Heisenberg]

Today on my way to work I've experienced the following thing. The rear brake pedal lost it's resistance while being pushed. Also the rear doesn't make any braking now. I suppose that happened after some hard braking when that $#@&* cage driver did that awful thing. I've made a fast look around the bike - no braking fluid leakage.
Is it some kind of common issue?

 

[HansO]

Today on my way to work I've experienced the following thing. The rear brake pedal lost it's resistance while being pushed. Also the rear doesn't make any braking now. I suppose that happened after some hard braking when that $#@&* cage driver did that awful thing. I've made a fast look around the bike - no braking fluid leakage.
Is it some kind of common issue?

not heard that before better you check the piston in the master cylinder seem strange you could not find a fliud leak I can only think the piston seal failed but then I would expect to see fluid come out of mastercylinder You could try bleeding the brakes but then you would have to ask how did you get air in there is your mastercylinder full also how low are your pads

 

[Heisenberg]

not heard that before better you check the piston in the master cylinder seem strange you could not find a fliud leak I can only think the piston seal failed but then I would expect to see fluid come out of mastercylinder You could try bleeding the brakes but then you would have to ask how did you get air in there is your mastercylinder full also how low are your pads

Thanks for the input Hanso. I've just checked it once more - the rear brakes appeared. The resistance of the pedal is normal.

 

[Mittzy]

Maybe the rubber seal on the master cylinder has failed causing the brake fluid to bypass the seal, this or air in the system if you cant see fluid leaking.
Have you checked you fluid levels? Could be sucking air if too low.

 

[HansO]

Thanks for the input Hanso. I've just checked it once more - the rear brakes appeared. The resistance of the pedal is normal.

I would definitely try bleeding also check how much pad you have as if they are low it could have caused the piston in the caliper to jam

 

[Gothlander]

Change the brake fluid asap or it will happen again !!! When the fluid gets old it absorbs moisture and when it gets hot it turns to gas.

 

[Heisenberg]

Thanks for the info!

This weekend we will make that bleeding process together with my friend and change the fluid.

The interesting thing is that I visited our local dealer not long ago with a request to change the braking fluid. I'm suspicious that they just simply didn't do that because there were no signs of operation on the screws of the fluid box on the steering bar. Then I tried to turn them out - what a titanic force is needed?! The screws seemed to go bad after that so I stopped and the signs of that effort afe easily noticable.

Anyway I will put here some info of the results.

 

[bruce aussie]

Is your bike a roadster with ABS if you jump on ABS to the verge of locking up the pedal or lever will pulse and feel weird thats ok just means it's working.

Ignore this I misread your first post

 

[albertaduke]

I guess with all the good advice posted you should find the reason for the troubling experience of finding no brake pressure when you need it , however from what I read on your first post you suspected that after some hard rear braking ( like panic braking ) caused by a inconsiderate cager you might have had a problem with the rear brake assembly.
May I humbly suggest you treat the rear brake with gentleness and do the hard braking with the front brake it may save your hide someday mashing the pedal generally cause the rear wheel to lock up instantly then fishtailing start and if you release the pressure on the pedal a good chance you will high side with awful consequence while using the front brake the bike will stay upright the braking distance will shorten and nothing untoward will occur if you doubt my explanation just do the bicycle test walk a bicycle and squeeze hard the rear brake while walking see what happen (rear lock up but you can keep walking with hardly any resistance then do same with front instantly the bike will want to stop rear wheel come off the ground but you are not moving anymore )
by modulating the front brake pressure shy of lock up your stopping distance will be shortened a great deal more than using the rear
this is my pet peeve knowing that a lot of riders use the rear brake as the main source of stopping ..it is just a matter of time before you high side and some bike instructors teach that technique in some H-D bike school incredible!!
this matter has been posted by many but it must be reviewed and explained anytime some rider tell us he or she just slammed the pedal down
keep two fingers on the right lever in traffic get your foot off the pedal and try the technique you will be impressed by the result.
ok enough ranting !!

 

[atomsplitter]

+1 albertaduke.

85% of the brake force comes in the front (notice there are TWO disk brakes up there?). The weight shift goes forward even when you mash on the rear brake (and why it will easily break traction because there's little weight on it) so you get front end dive even applying ONLY the rear brake. That's why the front is your braking friend, as you brake hard the front gets more traction, the harder you brake the more traction available. Ever seen a STOPEE? Can't do that if the traction (friction) isn't there. If you have seen a stopee, ask yourself how effective the rear wheel brake is during that maneuver.

My rear pads are showing minimal wear after 40,000 miles, they are what came with the bike new. The fronts have been replaced twice. I may replace the rear pads due to age because pads can seperate from the backing plate, but I don't think I'll ever wear them out.

As to the lost braking, that's fresh. Keep us posted on what you find.