rear brake goes empty sometimes
 

the rear brake of my f650 GS (2000) sometimes goes empty, I mean, when I psuh it, it goes all the way down with no reaction at all. But after pumping a few times, it comes back to life again and this story rapeats all and all. what should I do? thanks.

You have air in the system, it needs bleeding. If you don't know how to do this, take it to a garage/friend/mechanic and get them to do it, and watch them so that you will be able to do it yourself in future:thumbup1:

Trophymick

Also check for fluid leaks.

should I look for a "pro" anyway ?
 

thanks for your kind advise, trophymick.
I also was guessing air bubbling because, this is condition is almost always appering when going down winding slopes; no problem otherwise. The bad condition of the brake fluid was the secongd guess; 'cause I didn't change it since I bought the bike some 3000 km ago. For there is no leaks as far as I can see, it's better be air or bad brake fluid - there wouldn't be much trouble. In fact, I would try to bleed all the fluid out and fill it back again (with dot4 ), then pump all the bubbles away, by myself, as I did before on a Kawa.kle500 ....but, nothing in the back seemed to be the same. so I just walked in some woekshop and asked some mechanic directly this wild question : "where is the bleeding valve of my BMW; it is just the same make like that red one stands there, before your shop?" . And,he politely grunted me to bring it in and not to try doing anything myself. wise enough, so, think I'll do that way. thanks again.