71 MASTER CYLINDER

[Richard B.]

COULD SOMEONE PLEASE TELL ME WHAT OD1 AND 9301 MEAN ON A 1971 MASTER CYLINDER

THANK YOU

[Joe L.]

Re: 71 MASTER CYLINDER

Richard-----

If you are referring to CASTING marks (i.e. characters that are created by the pattern/mold when the part is cast), I don't know that anyone has figured out definitively what they mean. They often vary widely from one casting to the next. I have not noted the "OD1" you describe on original Delco-Moraine castings. However, I don't doubt that it may be on some. If the master cylinder is a "509" casting, it may refer to the fact that it's designed for a 1" finished bore size. All 1971 Corvettes with manual brakes used a 1", "509" master cylinder.