There might be a serial number on the side of the frame either on the right side or left might have to scrape some to find it but should be there.

This might have two master cylinders on it,one on the right side for the brakes and another on the left for the inching system.Sounds like the system needs bleed of air if you pump it and it builds pressure,or the master cylinder is bleeding off and needs replaced.

The milky hyd. fluid sounds like it has alot of water/moisture in it,would recommend changing it and the filter.
This might have the flat head continetal engine in it,the oil dipstick should be down on the block on the right or left side not positive off the top of my head,thinking right side,does this have a spin on filter or a paper cartridge filter that goes in a housing?