liquid leaking into cab

Sounds like a cowl rebuild to me. The reason I am saying that is that this is a common thing to go wrong with these. You may find the top hats or at least one are rusted out letting the water come in there.

 

I'm positive its the rubber seal around the door. I can see where its leaking in. Its not the cowl.

 

The seal is so old its flattened out in one spotand no longer makes contact wwith the door. I can even see through the crack when the door is shut

 

Ok, ?

 

And how did the water get down inside there?

 

Inside where?

 

and..."its radiator fluid that's leaking in the cab"...

you may have two leaks...