Bench Bleed Master Cyl Question

So unbelievably I have another update on this. Cleaned the garage real nice today, psyched about finally installing the master. Tried a bench bleed and SAME S**T AGAIN. No fluid pumping from the front reservoir and tight, choppy operation. WTF ?? After much head-scratching and troubleshooting I found that the culprit is the stop / lock bolt that screws into the bottom of the master. When it's tight it's locking-up the front piston. If I remove it everything works fine. When it's installed everything still works but only until the bolt is tightened, then it locks the piston up. The only purpose I can see that this bolt serves is to keep the pistons from coming out of the bore, which would be a bad thing however there's also a plate at the rear of the master (that the bellows attaches to) that essentially serves the same purpose. The only solution I can come up with is that instead of grinding down the original stop bolt, which would have worked but I didn't want to destroy it in-case I need it again some day, I got a new 14/28 x 1/2 bolt, cut it down shorter, and installed it with an 0-ring. No, I'm not crazy about this solution but it's NOT gonna work any other way. Another weird thing is the rebuild kit came with a lock bolt that is completely different from the original. (smaller diameter and it has a long pin end). If you ever have 10 hours to kill you can find similar unexplainable situations that I have encountered when re-assembling this car.