1200 Where Has My Rear Brake Gone?!

First ride out today after the lock down, ended prematurely as the rear brake on the 2018 monster 1200 quit. It worked fine when put into the garage in November but not today! Pedal goes all the way to the exhaust with finger pressure. There is no sign of fluid loss, any ideas?
I am tempted to bleed it but why would this happen? It is not that it is spongy it just does not exist. Presumably caused by air in the system or master cylinder seal failure?

 

Thanks for your comments. Something must be amiss with the system as we did a few thousand miles on it in Ireland at the back end of the year just before it was put away and it was absolutely fine then. My multi came out of the same period of hibernation without a problem. It’s booked in at the dealer for a service at the end of the month so it will be sorted then. I will bleed it in the interim so it can be used in the meantime. The front brakes are fine but they are linked aren't they?

 

I stand corrected, they are not linked, thanks for the heads up, just as well!

 

thanks for posting this Edge of Town, I did not pick it up in my original search. Looking at that thread there are similarities and it could well be the same problem. The obvious difference is my lack of brake was only noticed when it came out of the garage having been laid up in November and during the virus clamp down rather than being noticed whilst in use.

My rear brake pedal can be pushed down with one finger tip and very light pressure to the point further travel is only limited by the underside of the pedal hitting the exhaust flapper valve boss. If the lever return spring was not there the pedal would be resting on the exhaust or limited by the maximum extension of the master cylinder mech. No braking effect is evident at all. It’s like there is no brake fluid in the system. I have experienced braking performance being kept at top notch by bleeding but never, in all the many bikes I have owned, have I Experienced this.

It is still very much in warranty so I am tempted to let my dealer sort it - they are exceptionally good at sorting any issues that arise with bikes they supply it’s just a pity they are not yet fully up to speed after the clamp down and we have this glorious weather to ride in!

 

Mrs a call from them Friday to rebook the service which was cancelled due to the clamp down but that is first week June. I will give them a call Monday and hopefully catch them then.

Reading your post got me thinking about the routes you helped us with when we visited your part of the world. Our ride along the Connor pass still brings a smile to our faces!

 

Dealer did a great job and fitted the bike in, brake bled so symptoms treated. Apparently it happens. Having worked for a company supplying high end sealing products I am not in the least convinced by the explanation but at least the brake is restored and the Mrs feels happy riding it. - until the next time......

 

Pretty much spot on! “Seal relaxed and air got in” or words to that effect. Bike presented last week with same symptoms. My bike came out of the same hybernation no issues...

 

Really crap design, or quality control or both. Good news is the bike has four more years of warranty!