My rear master cylinder was leaking fluid due to a corroded lid. tI removed the master cylinder and the brake pipe by removing the banjo bolt simply because it would be easier to clean up everything off the bike.
I have now refitted everything, topped the master cylinder up and attempted to bleed the brake, leaving lid off. Initially the first few times I pressed down on the rear brake pedal air bubbles escaped into the fluid in the master cylinder. Now nothing and the pedal doesn't harden.
Is there a trick to bleeding the rear brake or is it possible my master cylinder is not working properly, maybe needing replacement parts?