What is the logic of banging DOWN on a crankshaft to remove aflywheel?
 

On Jul 12, 12:20*am, "Bob F" wrote:
James H. wrote:
What is the logic of banging DOWN on a lawnmower crankshaft in order
to lift a flywheel UP?

In another thread, I asked about how to repair a lawnmower that hit an
obstruction and started running badly and then not at all. You guys
correctly ascertained it was a bent flywheel pin (mine was shaped
like a Z).

I tapped two holes in the flywheel with a 1/4x20 tap and easily
removed the flywheel with a harmonic balancer puller but only after I
broke the intake manifold in half trying to bang down on the
crankshaft as I pryed up with a pry bar.

In the end, I conclude that banging down on the crankshaft and prying
up with a pry bar is the wrong advice ...
(1) Prying up with a prybar can easily destroy the intake manifold,
for example ...
(2) Banging down on the crankshaft appears useless to me

My question:
Why do people recommend banging DOWN on a crankshaft when you want to
move the flywheel UP?

What's the logic?

The crankshaft isn't going to go down and the flywheel isnt' going to
go up when you bang on the crankshaft. It appears, to me, to be a
useless endeavor.

But, since so many people have said to bang DOWN on the flywheel ...
may I ask what is the logic in that?

I usually pry up "firmly" on the flywheel on two side (wooden wedges work well),
then tap downward on the end of the shaft (with the nut loosened to be flush
with the crank end). By lifting up, you raise the crankshaft slightly, takeing
up any play. Then when you tap the crankshaft, it applies instantaneous force
way higher than you could ever get by lifting the flywheel. The mass of the
flywheel resists the momentary force, so the crankshaft loosens.

Good instructions...I would only add...use a large brass mallet (if
available). The shaft is tapered and resists separation from the
flywheel.
Pullers do not work as well.