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reverse unit fix

How to fix sticking AF reverse units

By     "David J. Dewey" <>

    This is a common problem that can vex everyone. Get out a pair of *strong*
magnifiers and look at the brass lift lever and the hole it runs in. AC
made the frames with a die stamp, and as the die wears, the holes develop
rough edges. The rough edge slowly cuts into the brass lever backside,
making a fine notch that acts as a wedge when the coil lifts it to the top
of the hole, and holds it there (it doesn't take much, apparently!).
        My 'fix' for this is to use a fine jeweler's file on the hole, to make
sure the edges are smoooooth, but being careful not to enlarge the hole!
(BTW, this is best done w/ the drum out and by carefully pushing the lever,
you can get it out of the hole too.) I then smooth out the back edge of the
brass lever, and then buff w/ my buffing wheel (you could use a Dremel(R)
[Let's keep the Lawyer's happy!] tool with a buffing wheel & some red
rouge). You want the brass lever to be smooooth on top, and on bottom, so
it can slide off the plastic ratchet on the drum, and not dig into it either!
        After you assemble it, you may need to adjust the lever so the drum stops
centered under the fingers.  Be aware that some repro fingers are longer
than the originals!  I have had to often resort to 'making them right'
usually by making the 'U' contact area more pronounced, effectively
shortening them.
        Carefully done, the E units can be reliable. I have on my repair result
sheet a '12 cycle' test for every loco before it leaves me. If it 'hangs'
in any of these cycles, I go over it again.
        Oh, yes, residual magnetism in the bottom plate can hang them too, but
this usually only happens if you're running them on DC!
        Is this all clear as mud????

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