John Deere stx38 - Manual (Page 270)

6 - 38
3/21/97
REPAIR HYDROSTATIC POWER TRAIN
PUMP, MOTOR, AND CENTER
BLOCK—DISASSEMBLY
IMPORTANT: Loss of Hydro Power—
STX38 (M00STXC210001—270000)
STX38 (M00STXJ270001—290000)
STX46 (M00STXG240001—270000)
STX46 (M00STXL270001—290000) One or more
piston springs may be missing in the pump or
motor cylinder block. With the spring missing,
piston washer may slip out of piston and
damage surfaces of the cylinder blocks, plates,
and center block.
IMPORTANT: READ THIS PROCEDURE
COMPLETELY BEFORE PROCEEDING. Pump,
motor, and center block assembly is under
CONSIDERABLE PRESSURE. Do not allow
assembly to FLY APART or damage may occur
to many finely-polished, machined components.
PAY CLOSE ATTENTION to the ORDER and
ORIENTATION of ALL COMPONENTS to their
neighboring components. Mark them, if
necessary. This will help greatly when its
assembly time.
1. Visually check overall condition of assembly,
without removing any components. Look for
scoring, pitting, discoloration, worn or broken teeth
or splines, or other detectable damage.
2. Remove port plug (D) and connector (E). Remove
and discard three o-rings (B). Replace o-rings
every time port plug and connector are remove.
3. Hold downward on entire pump (F), motor (A), and
center block (G) assembly with one hand as you
gradually loosen three cap screws (C) with the
other.
4. Keeping downward pressure steady, slowly remove
three cap screws (C) and spacer (H).
5. Without losing any pressure; reposition both hands,
one over the motor portion (I) and one over pump
and center block portion (K).
6. Now compress both portions together a little more
to allow you to walk rolled pins (M) and entire
assembly from upper case. Maintain pressure so
you do not scratch mating surfaces of motor
cylinder block (J) and finished-brass motor plate
(N) and pump cylinder block and its plate (L). Also,
do not scratch bearing races (O and P) on case
grooves while walking assembly from upper case.
7. Carefully move and separate motor, pump, and
center block assembly to workbench.
A
C
M58248
F
H G
D
E
B
B
C
M58209
J
N
L
O
P
Q
M
I
K