[AJD] Farm Wagon Restoration

[wb5cys]

I am restoring an old Electric Wheel Company running gear and I have a slightly off-topic question.

I want to remove the grease caps on the ends of the spindles to inspect and repack the bearings.  Is there an easy way to get these things off?  They look to be press-on and probably have never been removed.  I tried a pipe wrench but couldn't budge them.  If  I have to damage them to get them off, are they standard sizes?

Thanks - I could probably research the answers but I am being lazy.

Cal B.
Texas