Anyone know where I can either get a repair kit or rebuilt Aux. Rear Master Cylinder?

 

is your problem just that you have no feel? there is a poor design and air gets into them all the time. you have to bleed them forever with the cap off of the resivor. then you can usually get it to work if its not shot. just take your time and bleed it alot and you should get it back. and as far as a rebuild kit there is not one you have to buy the whole new master cylinder which looks up to be $115.49.

 

Thanks, I'll bleeding it longer.