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Old 04-04-2013, 11:16 AM   #23
Snowhite808 OP
Gnarly Adventurer
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Joined: Feb 2012
Location: Northern EU
Oddometer: 107
Leaking and non functioning rear brake light switch.

Yesterday I visited the garage, to check the oil levels, install the swing arm protectors and wanted to check if all the lights and farkels are working on the bike or not.
Needless to say - did not go that well.

After letting the bike warm up and taking a little run up and down the garage - I started checking the lights. Turning signals ok, number plate ok, front light ok, front brake ok, rear brake - non existant...

Switched off the bike and rolled back in to the garage. It was time to strip stuff again. Well - checking the wiring - basically right next to the master cyl on the rear is a small white connector for the switch that You can reach if You take off the right side rear fairing. Use a paperclip or similar, to short the wires in the connector and You should get brake light. If not - one needs multimeter to check the voltage and contacts and such. Mine worked right away. Meaning, the problem lies with the sensor. It is a brembo unit that mounts right on the cyl and works off of the oil pressure produced by master cyl in the brake line banjo bolt. There are 3 reasons why this is a crappy solution.
1 - the electric wires are not very protected and run 1/4 of an inch from the hot exhaust pipe.
2 - the sensor works by dirty oil pumping in the banjo bolt (easy to overheat, get stuck and just have an air bubble there
3 - this little switch has an effect on the function of the rear brake. The accuracy and reaction all go together with the performance of the brake. The affect is small, but it is there.

+ one problem that I had with my switch - the frieken thing was leaking.

So I took off the brake cylinder and and the switch and brought it home.
The switch worked if I really forced some small allen key into the pressure point. But no matter how I tried to clean or make it better, nothing helped.
So off to internet and the part is - 50311051100, costs about 14,55 EUR
and was on the shelf at the local dealer.
here the new vs old pic -

Take everything back, remember to use new copper seals if You put everything back together. Here is the pic of the brake line and the position.
Need some ideas to route the wire, so it wount get "soldered" by the hot exhaust.

Then bleed the whole system properly and check if all is good.
Mine was, so I did another run in the garage and took 2 pics of the beascht.

Snowhite808 screwed with this post 04-04-2013 at 11:20 AM Reason: Spellin problems
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