Hi, I have a problem probably with main brake master cylinder (I did not found visible leaks or hissing) on my robin hood 2b (no servo). Brake pedal is soft and after few presses it gets firm but if I keep pressing it goes slowly down to floor. I've found out that my brake master cylinder is type TRW PMH224. But it's quite difficult to buy it here so I am curious if this master cylinder can be changed for another one form Sierra without abs - for examle for ATE 010463 or simmilar. Thank you very much for replies. :-)