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Massey Ferguson 7624, 7626 hydraulic system – right-hand cover
Massey Ferguson 7624, 7626 tractors may be fitted with a 150 l/min flowrate Load Sensing circuit.
The right-hand side hydraulic cover of this circuit is fitted on the intermediate housing as is the 110 l/min flowrate Load Sensing circuit.
The cover serves as a support for numerous components and contains
various channels for the booster, lubricating and low flowrate circuits.
On its internal face, the cover contains:
- an idler pinion (82) also known as the "relay" pinion.
- the safety valve (44) of the booster and lubricating circuit
calibrated at 5 bar.
- the safety valve (45) of the low pressure circuit (17 bar).
On its external face, the cover is fitted with:
- the variable displacement pump (41) and its regulator (12)
- the main 15 micron filter (27)
- one or two priority block(s) (7) (depending on assembly) serving the
various functions of the low and high flowrate circuits
- the high pressure relief-valve (2) calibrated at 230 bar
- the four solenoid valves (15) to (18) controlling the low pressure
functions (depending on options) one of which (power take off clutch) is
of the proportional type.
- the high and low pressure diagnostics connectors (11) (48), booster
(lubrication) (29) and Load Sensing (9).
- the low pressure (14) and booster (42) switches as well as the
clogging indicator (34) of the main filter (27).
MF 7624, 7626 Hydraulic routing
- The engine movement transmitted to pinion by shaft drives the variable
displacement pump pinion via the "relay" pinion (82).
- The oil coming from the booster pump located on the left-hand cover
flows into the priority block(s) (7) (depending on version) via the main
filter (27) and the variable displacement pump (41).
- The tube (55) sends the oil coming from the 5 bar safety-valve into
the suction manifold of the booster pump when no hydraulic slave device
is used.
(1) Bolt (2) High pressure relief-valve (3) Orbitrol spool valve supply
port (4) Bolt (5) Load Sensing control port from Orbitrol spool valve
(6) Load Sensing control port to pump regulator (7) Priority block(s (8)
Cover (9) Load Sensing diagnostics connector (10) Return pipe (11) High
pressure diagnostic connector (12) Pump regulator (13) Load Sensing
union (14) Low pressure (17 bar) switch (15) Solenoid valves: power take
off, power take off to brake, differential lock front and rear if fitted
and
(18) 4WD (19) Hydraulic cover assembly (20) Park Lock union (21) Power
take off clutch port (22) Mecanindus pin (23) Power take off brake (24)
2WD or 4WD differential lock port (25) O’ring (26) Port for 4WD union
(27) 15 micron main filter (28) Low pressure port (29) Booster pressure
and lubricating diagnostic connector (30) Supply port for lift control
valve and auxiliary spool valves via the manifold (31) Load Sensing
control port from auxiliary spool valves and lift control valve (32)
Bolt
(33) Control port of trailer brake valve (34) Clogging indicator (35)
O’ring (36) Centring pins (37) Nut (38) Washer (39) Pump pinion (40) Key
(41) Variable displacement pump (42) Pressure switch (booster and
lubrication) (43) Port to lubricating manifold located above centre
housing (44) 5 bar safety valve
(45) 22 bar safety valve (46) Plug (47) Bolt (48) Low pressure
diagnostic connector (49) Rivets (50) Port to trailer braking quick
disconnect coupling (51) Transfer pipe (56) Composite seal (O’ring and
anti-extrusion bush) (57) Dust cover (58) Sleeve (59) O’ring and dust
cover (60) O’ring and dust cover
(61) Composite seal (O’ring and anti-extrusion bush) (62) Dust cover
(63) Suction manifold and bolt (64) Discharge manifold and bolt (65)
Lubricating port for relay pinion (66) Port to brake power assistance
(67) Studs (68) Nuts (69) Plug (70) Closing plate and seal (71) Plug
(72) Spacer (73) Bolt (74) Obturator and seal (75) Bolt (76) Washer (77)
Bearing cone (78) Bearing cup (79) Shim(s) (80) Circlips (81) Spacer
(82) Idler pinion (83) Pin (84) O’ring
(22) Mecanindus pin (52) O’ring (53) O’ring (54) Booster pipe (55)
Safety valve (44) pipe, A - Suction, PCV - To variable displacement pump
(41), VS - 5 bar safety valve (44), C - Intermediate housing compartment
Removing and refitting the cover
Immobilise the MF 7624, 7626 tractor. Chock the left rear wheel. Chock
between the frame and the front axle. Partially drain the intermediate
housing. Disassemble the right rear wheel. Position an axle stand.
Removing the priority block(s)
Proceed with the removal of the priority block(s) by removing bolts (4)
after previously disconnecting hose pipes (3) (5) (6) (28) (30) (31)
(50).
On Massey Ferguson 7624, 7626 tractors fitted with trailer braking,
remove the priority block(s) (7) without disconnecting hose (33).
This precaution will avoid bleeding of the valve pilot circuit when
refitting the cover.
Removing the cover
Disconnect pipes (10) (21) (23) (24) (26) (43), the solenoid valve
harnesses (15) to (18) (depending on the version) and switches (14) (34)
(42).
Take out bolts (32) and remove the main filter assembly (27). Remove
bolts (1) and nuts (68).
Check that there is no hydraulic or electrical link that remains
connected between the cover and the intermediate housing. Release and
remove the cover.
Certain nuts and bolts on the cover are difficult to access. Where
necessary, use a locally manufactured wrench. After removing the cover,
take out pipes (54) (55) (optional).
The 22 bar safety valve (45) comprises: circlip, stop, spring (3) and
valve.
Refitting the cover
Check for the presence of rivets (49) at the end of the channels located
on the external and internal faces of the cover. Clean the mating faces
of the housing and the cover.
Check for the presence of the two centring pins.
If removed:
- place seal (53) on pipe (55). Position the end of the pipe in the
Mecanindus pin (22) located on compartment "C" of the intermediate
housing.
- place seal (52) on pipe (54). Position the machined slot of the flange
in pin (1). Lightly smear the seal (4) with miscible grease and stick it
to the flange.
Check the location of the pins (67) in the intermediate housing.
The pins are first lightly smeared with Loctite 241 before fixing them
on the housing.
Smear the mating face of the housing with Loctite 510 or its equivalent.
With the assistance of another operator and the tool recommended in the preceding remark "Danger", refit the cover by aligning its holes with the studs on the housing.
Push the cover progressively while simultaneously checking between housing and cover mating faces that the 5 bar safety valve is correctly housed in pipe (55).
Tighten bolts (1)
and nuts (68) to a torque of 120 - 160 Nm.
If there is any resistance, stop tightening and open the gap between
housing and cover to check on the correct alignment of pipe (55) and the
5 bar valve.
Refit the main filter assembly (27) and tighten bolts (32). Reconnect
the harnesses to the solenoid valves and switches. Carry out operation
in reverse order.
Refitting the priority block(s)
Refit the priority block(s) and check for the presence of seals. Tighten
bolts previously smeared with Loctite 542 to a torque of 25 - 35 Nm.
Reconnect the pipes or hoses. Carry out operation in reverse order.
Refit the rear wheel. Remove the axle stand. Tighten the wheel nuts or
studs (depending on version). Top up the oil levels in the housings and
check the transparent tube on the left-hand side of the centre housing.
Remove the chocks.
Start the engine and check:
- the operation of the hydraulic and electrical components
- the oil tightness of the mating faces, pipes and hoses.
- If the variable displacement pump has been replaced, carry out
hydraulic tests. Carry out a road test.
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