It will not go together without that fitting! The opening in the side of the MC that the fitting goes into is a larger size than the normal smaller fittings your stock hard lines use. The numbers are wrong, but it would be like trying to screw a 10 mm bolt into a hole designed for a 12 mm one. In order to install that larger 1" MC, you have to get that fitting. It sucks too because it's a real weird piece and I couldn't find a duplicate in a parts store. You may be able to get one from an Acura dealership but I didn't try (I had one). It's a really stupid setup actually. It uses the same 3/8 line (not sure on the numbers, sorry, I did this last winter) as the rest of the system, but uses a fitting that would normally be used for a 1/4" line. The 1/4 fitting won't work becuase the center hole and seating surfaces are wrong and it won't seal (I believe). It's complicated, but suffice to say, you need that fitting to install that MC in your car. Good luck. Seeya.