Hi everyone; perhaps this question will also aid others besides myself, who've found themselves in this position: is there a book, (or source) for how to rebuild knee action shocks on a 40 Ford? Also, what fluid is used in them, & what numbers do the 40 shocks have on them to identify them as truly being 1940? I have a "pair" with different arm lengths, & different numbers on the arms. Every pair I've seen has mismatched arm numbers. Is this "normal"? Thanks in advance for any knowledge you can provide! John