Servicing; Hydrostatic Transmission - Kubota ZD221-48 Workshop Manual

ZD221. WSM
TRANSAXLE
[4] SERVICING
(1) Hydrostatic Transmission
3GZAAADKP069A
3GZAAADKP051 A
(1 )
(3)
3GZAAAIKP019A
Center Section
1. Check the surface (1) of center section for scratches or wear. If
deep scratch or excessive wear is found, replace the hydrostatic
transmission assembly.
(1) Surface
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Check and High Pressure Relief Valve
1. Check the check and high pressure relief valve assembly (3) for
scratches and damage.
2. Check the spring (2) for breakage and wear.
3. If anything unusual, replace the ball and spring.
(1) Plug (3) Check and High Pressure Relief
(2) Spring Valve Assembly
(4) Center Section
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Cylinder Block Assembly
1.
Check the cylinder blocks
(1)
and pistons (2) for scratches and
wear.
2. If scratch or worn, replace the cylinder block assembly.
3. Check that the piston (2) and spring (3) are in each cylinder bore.
4. Check the pistons for their free movement in the cylinder block
bores.
5. If the piston or the cylinder block is scored, replace the cylinder
block assembly.
6. Check the polished face (4) or cylinder block for scoring.
7. If scored, replace the cylinder block assembly .
• IMPORTANT
• Do not interchange pistons between pump and motor
cylinder block. Pistons and cylinder blocks are matched.
(1) Cylinder Block
(3) Spring
(2) Piston (4) Polished Face
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2-S23