simple question on Hydralic oil

[Mr. Du]

I have recently inherited a 1949 9N
A very cool old tractor.
However, back in 1949 they didn't publish Idiot Guides to these tractors.
A very basic question:
question: Where do I check the Hydraulic oil and where do I put the oil in ?
and how many quarts / gallons should go in there?

the reason I'm asking is there seems to be a leak on the right tire...an oil is leaking out. The only thing I can think is that it's hydraulic oil.

Advice ?

[razad]

I have a 1940 9n and currently restoring it. I just drained all the hydralic oil out from the bottom because of the brakes not working. When I'm ready to replace what they call a sure seal that should take care of oil leaking again. About five gallons of oil should replace what was drained out.