Toro Groundsmaster 4500-D Service Manual page 139

NOTE: Cleanliness is extremely important when
repairing hydraulic components. Work in a clean area.
Before disassembly, drain the oil, then plug the ports
and thoroughly clean the exterior. During repairs,
always protect machined surfaces.
Disassembly
1. Plug all ports and clean outside of valve thoroughly.
2. Remove spool caps (10). Do not remove retaining
rings (13) from spools unless spool spring (15) is bro-
ken.
NOTE: Spools and spool bores are matched sets. Be
sure each spool is identified with the correct control
valve body spool bore.
3. Remove spools (4) from control valve body (11).
4. Remove bushings (8) and O--rings (12) from spools
and O--rings from spool bores.
5. Remove plugs (6).
IMPORTANT: Check location and positioning of
plungers when removing from body to assure prop-
er assembly.
6. Remove seat retaining plugs (7), lockout springs (9),
poppets (1), seats (5) and plungers (2 and 16).
7. Remove plug (21).
8. Remove detent plugs (18), discs (19), detent springs
(20) and detent plungers (17).
9. Remove all O--rings and back--up rings from all plugs
and seats.
Inspection
1. Remove all nicks and burns from parts and inspect
for excessive wear.
2. Inspect all plungers and poppet seats for burrs or
roughness.
3. Inspect spool springs (15), lockout springs (9), and
detent springs (20) for breakage.
4. If spools (4) have excessive wear, the control valve
becomes non--serviceable as the spools and spool
bores are matched. Damaged spools cannot be re-
placed.
Groundsmaster 4500--D/4700--D
Assembly
1. Thoroughly clean and dry all parts. Apply a light coat-
ing of clean hydraulic oil to parts prior to assembly.
NOTE: All O--rings, back--up washers, wiper seals and
nylon poppets should be replaced as new items.
2. Install new O--rings (12) in proper grooves in spool
bores.
3. Install plugs (6) with new back--up washers (29) and
O--rings (28). Torque plugs from 30 to 35 ft--lb (41 to 48
N--m).
4. Lubricate plungers (2 and 16) with clean hydraulic oil
and install them into their correct position in valve body.
IMPORTANT: Check location and positioning of
plungers during installation.
5. Install new O--rings (25) on seats (5). Install new
back--up washers (23) and O--rings (24) on plugs (7).
6. Lubricate seats (5) with clean hydraulic oil. Install
seats (5), new poppets (1), and seat retaining plugs (7).
Torque plugs from 30 to 35 ft--lb (41 to 48 N--m).
7. Install plug (21) with new O--ring (27). Torque plug
from 10 to 12 ft--lb (13 to 16 N--m).
8. Lubricate detent plunger with clean hydraulic oil.
Install detent plunger (17), detent spring (20), disc (19),
and detent plug (18) with new O--ring (26). Torque plug
from 4 to 5 ft--lb (5 to 7 N--m).
9. If retaining ring (13) has been removed to replace
spool spring (15), install washer (14), spring (15),
spacer (3), and secure with retaining ring (13).
10.Slide bushings (8) over spools. Slide new O--rings
(12) over spools and position next to bushings. Dip
spools in clean hydraulic oil and install spool assemblies
into proper location of body.
11. Install spool caps (10) and tighten from 20 to 25 ft--lb
(27 to 33 N--m).
12.Install new wiper seals (22).
Page 4 - - 101 Hydraulic System (Rev. A)