Keep in mind lots of halfhearted taps with a hammer is a good way to swell the pin making it even more difficult to remove.
Be serious about it, use a solid bar just smaller than the pin and swing a big hammer like you mean it.
If a lick or three doesn't present any movement wait, heat, and try again later.

EDIT
I may be confused. I have been thinking about 3/4 ton and larger which have a straight pin and a cross bolt to secure it. If the 1/2 ton is similar then I haven't given you bad info....?

Grigg

Last edited by Grigg; 07/29/2013 3:14 PM.
•1951 GMC 250 in the Project Journals
•1948 Chevrolet 6400 - Detroit Diesel 4-53T - Roadranger 10 speed overdrive - 4 wheel disc brakes
•1952 Chevrolet 3800 pickup
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"First, get a clear notion of what you desire to accomplish, and then in all probability you will succeed in doing it..." -Henry Maudslay-