My Suggestion would be to use a very very small dab of greese on the external support points where rests the axle that runs into the pneumatic motor and carries the external blades (Usually cardboard), working the axle back and forth only as far as it will go without strain. I would not use light oil because of the possibility of the wood swelling. If that doesn't help, do the same where the axle enters the motor body.
The Motor itself is, in my case at least, simply a water-wheel shape that fits very closely inside the barrel of the motor body. Mine has an open conduit to the resevoir on one side, and an exhaust (or intake) valve opened and closed by the Vox Humana stop. On many organs I understand that the body is sealed with glue and is a pain to disassemble and reassemble. I have seen organs where the internal blades are worn or broken and drawing the stop drains the resevoir silencing the instrument; and others where the chanel has been blocked by some serviceman to save the effort or expense to repair the problem. Anyone who has successfully repaired the interior of the motor are better qualified that I to suggest how to proceed.
Lee
If you can keep your head
when all about you are losing theirs
and blaming it on you
Its just possible you haven't grasped the situation.