In a hot industrial environment we use to pull the fitting and squirt Sili-Kroil (we simply call it Kroil here) into the hole and let it sit long enough to smoke a cigarette then shoot the grease to it....I'd say at least 95% of the time it worked.

1937 Chevy Pickup
In the Gallery
1952 Chevy Panel
In the Gallery
More photos
1950 Chevy Coupe
Pictures!

I'd rather walk and carry a Chevy hub cap than ride in a Ferd.
I can explain it to you, but I can't understand it for you smile