Hartzell HC-D2MV20-3 Series Owner's Manual And Logbook page 138

(2) Hydraulic Unit Removal for Propeller Model
HC-D3(MV,V)20-6L
CAUTION 1:
CAUTION 2:
(a) Grip the push rods and forks that protrude from the
jack plate unit attached to the hydraulic unit piston.
(b) Pull the piston and the attached hydraulic valve away
from the cylinder until it is free from the cylinder.
(c) Remove the six locking nuts from the six studs that
retain the cylinder to the engine case.
(d) Place the hydraulic unit piston and cylinder and
associated parts on a cart for transportation.
INSTALLATION AND REMOVAL
Propeller Owner's Manual
140
USE ADEQUATE PRECAUTIONS TO
PROTECT THE HYDRAULIC UNIT
FROM DAMAGE WHEN IT IS REMOVED
FROM THE AIRCRAFT ENGINE AND
WHEN IT IS STORED.
OIL WILL BE RELEASED FROM THE
CYLINDER AND PISTON CAVITY WHEN
THE PISTON IS REMOVED FROM THE
CYLINDER. PLACE A PAN UNDER
THE HYDRAULIC UNIT TO CATCH
RELEASED ENGINE OIL.
61-00-40
Rev. 2 Jun/12
Page 3-72