I have a couple of methods for removing a grand pump.  None of them are
easy but I will go through them all:

1. The safest method -- put the piano on the side, slide the pump out.
This is very cumbersome and needs enough strong men to lift the piano.
First remove the pedals, unscrew the front bass leg screws, get the
team to lift the piano while someone removes the leg.  Slowly put the
piano down and gently rotate it to its side.

2. A difficult, cumbersome but somewhat safer method -- use a stool
with a rotating top, like an old organ stool.  Rotate this so that it
supports the pump.  Unscrew the supports for the pump, gradually remove
them.  Gently lower the stool until eventually it is beneath the level
of the piano, remove the stool while supporting the pump (two men are
good here), lower the pump.

3. The down and dirty method (what I do) --  Make sure you have a good
set of screwdrivers and everything you need handy because once you
start you can't stop.

a. Lie on your back with your knees pressed up against the pump.
b. Remove the screws.
c. Lower the pump slowly and gently.
d. Place it on the floor and get out of there.

The pump is heavy, but not so heavy that it will crush you if you
control it always.  I can _easily_ lift it with my legs and I'm not
afraid to do so.  The problem is that when you put it back, it always
happens that one of the screws will roll out of the way or else I can't
find the screwdriver while I'm under the piano supporting the pump.
Great fun!

Eli Shahar