I have an '84 with apparently the original sliding windows.  I have never
been able to get sliding windows to lock.  This past weekend, I took the
latches apart and made sure the springs were there and still working.  If I
raise the sash about 1/32 of an inch, the locks work, but I have been unable
to get a shim under the sash to keep it in position.

In a few weeks, I need to take van to location where I definitely need to
lock it up tight.  What do I need to do to fix this problem?

John