warped main action rail?

[John M. Formsma]

List,

The piano is a Wurlitzer studio console approximately 25-30 years old. I
removed the action to replace the bass strings because most of them were
universals. While the action was out, I did the following:

--filed hammers
--tightened action screws
--tightened action bracket screws because they were shifting a bit in my
hands The bottom ones were not needed tightening as much as the ones screwed
to the spring rail.

When I put the action back, it was difficult to get back into place. I.e.,
it felt like I had to put unnecessary pressure on the brackets to force them
to fit back on the action bracket bolts. I checked to see that all the
brackets were properly fitted on the bottom ball bolts, and they were, so I
thought little of it until...some of the notes from about F3-D5 barely
sounded because their dampers were not being activated properly. Since the
action did not seem to fit into place correctly, I assumed that maybe it had
been put back wrong. Took it out again, put it back in. Same problem. Took
it out again, stared, scratched, etc., put it back in. Same problem, so I
adjusted the spoons per note, put it back in. Better, but not at all
satisfactory. In the midst of taking the action out and putting it back in,
I noticed that if the two middle action brackets were not all the way up
against the bracket bolts, the dampers worked much better, allowing the
notes to sound. Scratching a bit more, I took the action out again...this
time to stare (and swear). Noticed after some staring that the main action
rail looked warped--bowed in the middle with the bow towards the keyboard.
OK, so I go to put the action back in, decided to test, but noticed that the
bottom ball bolts on the extremes were both leaning towards the soundboard.
(Would make sense if the rail were bowed.) Bent them back where they were
more supposed to be (visually), put action in. Same problem. Then I loosened
the two middle action bracket screws which attach them to the main rail. The
notes begain to sound normally--i.e., they were not damped all the time. So
I figure that the problem must be a warped main action rail. Does this sound
like it?

If this is the problem, what is the solution? I have thought that shims
could be put between the rail and the middle action brackets, forcing the
bow out of the rail. Or, what might be better if it would work, to take two
pieces of thin metal, drill a hole in one of them, insert one metal plate in
between the rail and side of bracket. The other adjacent to it (also in
between rail and bracket) would have a hole that is threaded, allowing a
metal screw to be inserted and screwed in to contact the back plate, forcing
the bow out as needed simply by turning the screw. The ability to make
adjustments would be better this way, right?

This is a brand new problem to me, and I've never had to think of a
solution. Would this work? Have I misdiagnosed the problem? Any suggestions?
One other thing that may help in diagnosis is that there was lost motion,
which felt more particularly acute in the middle section. This could be
caused by a bow, right? However, there was some lost motion throughout.  I'm
not done much on the regulation stuff yet, so I will get a chance to learn a
bunch on this one, I'm sure.

What I did was to leave the two middle action bracket screws untightened to
minimize the bow and allow "normal" sound. I have to go back to retune the
bass strings, and will need to solve the problem I have discovered at that
time.

Any help would be so greatly appreciated!  Thanks.

John Formsma
Blue Mountain, MS