Rear Brake light

[badseed]

Hi,
My RT 125's rear brake light does not work. There is no problem with the front brake. How does the brake ligt work? I did not see any circuit cable around the brake lever arm. Is it triggered from an other place? There are 3 cables at the back of the light. One is ground and are the two others seperate for each brake signal?
Thx

Ugur

[DAVID THOMPSON]

there is a switch on the rear brake master cylinder
mine went bad
short the wires together at that switch.. if the light comes on switch is probely bad
i recomend that you replace it with a mechinical switch of some kind
as i am still trying to get the air out of my rear brake system
older bikes had a switch and a pull spring and you dont have to
mess with bleeding the brakes

ar dave rt125 in wv usa

note at the tail lamp
one wire is groung usuall brown on german bikes
one is nite and day time run
and the brighter of the 2 filements is stop

[badseed]

I found the switch and short circuit the cable. The light came out. Then I took out the switch to clean inside with a needle. I put it back then checked if it works. It worked only two times. I realized that I did not tighten hard and the brake oil came out of the cylinder. I went to the service and fixed the brake problem. But then switch started not to work again. Did you get a mechanical switch, the guys told me that they have never seen a switch like that. I most probably will order a new one from http://www.mzparts.de. It costs 12euro or sthing like that.

[DAVID THOMPSON]

if you have a bmw dealer in your area show it to his part man
it may be the same on a bmw i will look to see if there is a bmw number

looking at my notes from past work on my bike
aprilia number on parts bag is 8124479

mz part number = 9013198000 brake light switch

german =bremslichtschalter

PAGE in MY Parts BOOK = FO9 B3 item 6
same page item 7
also order 2 of 9013199000 sealing ring (dichtring) or copper washer
i can email parts page if needed
you may have to force brake fluid through the system backwards
from the caliper end to get the air out i am still not happy with the feel of mine
show this picture below to your parts man

word search rearbrakeswitch rbsw
aprilia number on parts bag is 8124479

[jbthumper]

Hi all,
I had the same problem with my rear brake pump on my sm....the swith works when the correct amount of presure(which is 5 bar for my bike)is applied through the pedal.....but when it leaks.....there won't be enough pressure....
what i did was i went to this aprilia workshop which a friend of mine recomended and changed the MZ switch with an aprilia switch....now it works fine.....(so u won't need to use those expensive BMW parts )

hope this helps!!

[badseed]

Did the aprilla switch fit to the MZ? Or did you have to do some additional stuff?

[DAVID THOMPSON]

aprilia number on parts bag is 8124479

its a perfect fit
mine came from mzna in a aprilia parts bag
ar dave

[badseed]

aprilia 8124479 is the original part. I paid 16euros and now rear brake light is working fine.
thanx a lot.