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Massey Ferguson 6465, 6475, 6480 - Carraro suspended front axle control unit
Technical characteristics
Nominal pressure - 250 bar
Hydraulic oil type - DIN 51524
Ambient temperature - Min -30C / Max +90C
Hydraulic fluid temperature - Min -30C / Max +70C
Type of hydraulic unions to ports P, T, A, B - M18x1.5
Type of hydraulic unions to LS port - M14x1.5
Filtration: maximum pollution level allowed in service fluid - NAS 1638
Solenoid valve - 25 Nm
Accumulator tightening torque - 200 Nm
Nominal voltage - 12 VDC
Parts list - (1) LS pilot flow (2) KSP1 accumulator (3)
KSP2 accumulator (4) RSP1 accumulator (5) Bleed screw (6) Solenoid valve
WV1 (7) Solenoid valve WV2 (8) Return (9) Supply from pump (10) Top ram
supply (11) Bottom ram supply
MF 6465, 6475, 6480 - Hydraulic description of
the control unit with Open Centre hydraulics
Parts list - (1) Front axle suspension ram (2) KSP1
accumulator (3) KSP2 accumulator (4) RSP1 accumulator (5) Bleed screw
(6) Solenoid valve WV1 (7) Solenoid valve WV2 (8) Control unit (9)
Filter (10) Proportional valve (11) Controlled non-return valve (12) 250
+ 20 bar pressure relief valve (13) 170 bar pressure relief valve (14)
High pressure inlet (15) To auxiliary spool valves, A - Upper ram
chamber, B - Lower ram chamber, C - Hydraulic channel, D - Hydraulic
channel, E - Hydraulic channel, F - LS pilot line, G - Hydraulic
channel, LS - Load Sensing pilot flow, R - Return to housing
Neutral position
In low position, chamber A of the ram (1) is empty. The suspension is in
contact with two mechanical central beam stops. In high position, the
ram is balanced by accumulators (2), (3) and (4). If the pressure in the
ram is too high (shocks received by the front axle), the pressure relief
valve (12) opens and the excess pressure is directed to the return. If
the ram position has changed, the position sensor value has also
changed. If after 3 seconds the sensor value does not match to the
calibration value, the calculator supplies the solenoid relevant
valve(s) (WV1 (6), WV2 (7)) to make the two values correspond.
Lifting position
When lifting, the two solenoid valves WV1 (6) and WV2 (7) are activated.
The WV1 solenoid valve (6) allows oil to reach the accumulators (2) and
(3) and chamber A of the ram (1). When the pressure in chamber B reaches
250 bar, the oil returns to the tank via channel C. Channel D also
supplies accumulator (4). Solenoid valve WV2 (7) allows priority for the
suspended front axle in pilot flow line F. The proportional valve (10)
stops the supply to the auxiliary spool valve and linkage. When the
pressure in the circuit reaches 180 bar, the circuit resumes its course
via the proportional valve (10) and supplies the linkage and auxiliary
valves.
Lowering position
When lowering, only solenoid valve WV2 (7) is supplied. The oil supplies
chamber B of the ram (1) via channel E. The pressure created in the
pilot flow line F allows priority for the suspended front axle. The
proportional valve (10) stops the supply to the auxiliary spool valve
and linkage. When the pressure in the circuit reaches 180 bar, the
circuit resumes its course via the proportional valve (10) and supplies
the linkage and auxiliary valves (15). The pressure in pilot flow line F
also allows the non-return valve (11) to open so that the oil in chamber
A returns to the tank via channel G.
Massey Ferguson 6465, 6475, 6480 - Hydraulic description of the control
unit with Closed Centre hydraulics
Parts list - (1) Front axle suspension ram (2) KSP1 accumulator (3) KSP2
accumulator (4) RSP1 accumulator (5) Bleed screw (6) Solenoid valve WV1
(7) Solenoid valve WV2 (8) Control unit (11) Controlled non-return valve
(12) 250 + 20 bar pressure relief valve (14) High pressure inlet
Neutral position
In low position, chamber A of the ram (1) is empty. The suspension is in
contact with two mechanical central beam stops. In high position, the
ram is balanced by accumulators (2), (3) and (4). If the pressure in the
ram is too high (shocks received by the front axle), the pressure relief
valve (12) opens and the excess pressure is directed to the return. If
the ram position has changed, the position sensor value has also
changed. If after 3 seconds the sensor value does not match to the
calibration value, the calculator supplies the solenoid relevant
valve(s) (WV1 (6), WV2 (7)) to make the two values correspond.
Lifting position
When lifting, the two solenoid valves WV1 (6) and WV2 (7) are activated.
The WV1 solenoid valve (6) allows oil to reach the accumulators (2) and
(3) and chamber A of the ram (1). When the pressure in chamber B reaches
250 bar, the oil returns to the tank via channel C. Channel D also
supplies accumulator (4). Solenoid valve WV2 (7) allows priority for the
suspended front axle in pilot flow line F.
Lowering position
When lowering, only solenoid valve WV2 (7) is supplied. The oil supplies
chamber B of the ram (1) via channel E. The pressure created in the
pilot flow line F allows priority for the suspended front axle. The
pressure in pilot flow line F also allows the non-return valve (11) to
open so that the oil in chamber A returns to the tank via channel G.
MF 6465, 6475, 6480 - Hydraulic description of the control unit with
Twin Flow Load Sensing hydraulics
The operation of the different positions (neutral, lifting and lowering)
of the hydraulic unit with Twin Flow hydraulics is similar to that
described. The only difference is that the hoses (pressure and LS) are
connected at different places.
Identification of ports
On the control unit
A - Supply (hydraulic chamber with a large section), B - Supply
(hydraulic chamber with a small section), LS - Load Sensing pilot flow,
P - High pressure, T - Return
On the tractor
LS - Load Sensing pilot flow, P - High pressure, T - Return
Massey Ferguson 6465, 6475, 6480 - Disassembling and reassembling the
control unit
Some of the following pictures may not show your exact hydraulic control
unit, but the procedure is the same. Remove any components that could
hinder control unit removal. If necessary, remove the tractor complete
control unit. Disassembly - Mark the position of accumulators (2) (3)
(4) on the control unit. Remove them. The accumulators may be of
different capacity depending on their position and on the front axle
model. Loosen the A screw of each solenoid valve. Split the B solenoids
from C spools. Unscrew the C spools from the control unit. Gather the
components.
Reassembly - Check the components. Replace any defective parts. Screw
the C spools on the control unit. Tighten to a torque of 25 Nm. Assemble
the B solenoids on C spools. Tighten the A nuts moderately. If
necessary, fit new seals on each accumulator. Install the accumulators
using the marks made during removal. Tighten to a torque of 200 Nm. If
removed, Install the control unit on the tractor. Install any removed
components around the control unit. Screw the control unit AV bleed
screw. If the control unit and/or one or more solenoid valves needed to
be replaced: check P and LS pressure at the control unit ports;
calibrate the front axle.
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MF TRACTORS SPECIFICATIONS |
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MF FRONT END LOADERS |
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MF TRACTORS MAINTENANCE |
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MF TRACTORS TROUBLESHOOTING | ||||
1652 | 1749 | 2620 | 2725 | 2805 |
3050 | 3120 | 3640 | 3709 | 4245 |
4455 | 5320 | 5455 | 5613 | 6150 |
6280 | 6480 | 6615 | 7618 | 7720 |