Technical Does this hub use screw in hub (grease) caps?

My car is missing the front hub grease caps and I think it uses the ones that thread in and not just knock in? AFAIK, these hubs/drums are from a 42-48, sound correct?

 

According to the BIG GREEN FORD PARTS BOOK 1936-45 Pass. Cars,Comm, 122" trucks used
front wheel grease cap with threads ,part # 68 1139. For 1946-48 Pass cars grease cap # 51A 1139 (without threads) was used. If you remove the big nut you'll be able to see right away if you have threads,

 

Yes I think that will be the best way too, thanks

 

41 Lincoln Continental used screw on caps on the hubs.

 

Actually, your hubs are '46-'48 & use press in grease caps.

 

Are there threads visible inside the lip where a cover would be installed?