Brake Master Cylinder Leaking

[600RMKrider]

I put a 6" riser on my sled and had to put a longer brake line on. Well needless to say these plastic units are pretty fragile! I totally wrecked the orginal trying to get the stock brake line off the master cylinder. So I bought a used one from the local dealer and I think I broke it when installing the new brake line, cause it leaks fluid. Both times I tryed to support the piston with grips before I twisted the line fitting. They are $250 new from the dealer.

Can these things be rebuilt/repaired?

How can you support the piston while trying to tighten the brake lie to the master cylinder?

Any helpfull advise you can think of?

Thanks to all who reply!!