Can i use any brake fluid in my Magura HS-33 rim brakes? or does it have to be the magura stuff?
What about brake lines? will any work? I may need to extend one of them.
No DOT fluid. It has to be Magura.
You might as well use the specific Magura line since you'll probably need the fittings.
You can use Shimano mineral oil, LHM auto brake mineral oil, and various other branded mineral oils often associated with hydraulic brakes (do a search of this forum - there's a big list of compatible brands somewhere).
In emergencies with no access to proper mineral oils, you could use low viscosity cooking oil or even water (but in warm weather only!).
I know all of the above liquids work because I've used them myself.