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Adjusting the TH7 Valve on the Accelerator MSI 40/50
TRANSMISSION INSPECTION AND ADJUSTMENTS
5. ADJUSTING MOTOR A 6VM DISPLACEMENT CHANGEOVER
A) CHECK MINIMUM DISPLACEMENT (MAX. SPEED) :
• The check is made driving the truck on level ground with the engine a full speed in forward drive.
• Connect two 600 bar pressure gauges as shown above. At maximum drive speed the two gauges should read the same. This signifies that both sides of the Servo piston are subject to the same pressure and the motor is at its minimum displacement.
HIGH PRESSURE REGULATION PRESSURE HIGH PRESSURE
A 6 VM DA Serial 60 A 6 VM DA Serial 63 REGULATION PRESSURE
CHANGEOVER PRESSURE CHANGEOVER PRESSURE
B) CHECK START OF REGULATION :
• With the wheels raised from the ground and the truck supported on blocks gradually apply the brake pedal to raise the pressure in the HP circuits (inching valve by-passed)..
• Watch the two gauges. When the HP gauge shows 200/250 bar the changeover pressure will drop then the
HP will continue to rise until it reaches the setting of the DR valve. (Changeover pressure : See specification for different trucks).
• The changeover point can be adjusted by the screw.
TRANSMISSION INSPECTION AND ADJUSTMENTS
C)MAXIMUM DISPLACEMENT : (MAX. TRACTIVE FORCE)
• To make this adjustment, the machine should be chocked (brakes locked).
The check is made at maximum IC engine speed in forward drive. • The switching pressure (large section side of control cylinder) must be around zero bars. • Adjust the control screw as required (tighten to increase the switching pressure, loosen to reduce). • A check on the tractive force (using a hook) should then be carried out (refer to “Hand book” for values).
ADJUSTING THE TH 7 VALVE ON THE ACCELERATOR MSI 40/50
ADJUSTING THE MACHINE TRAVEL STARTING POINT / 1050 RPM +50 -0
To make this adjustment, firstly check by by-passing the pilot circuit (TH7 valve on accelerator - TH7 valve on brake) that the start of control point of the pump has been set to 1000 rpm.
• Reconnect the pilot circuit.
• Place the machine on chocks with the handbrake off.
• Electric reverser in forward drive.
• Increase the IC engine speed gently and check that the wheels begin to turn at 1050 rpm. If required, adjust the TH7 valve by turning screw 91.
• Loosen to delay the start of control. • Tighten to advance the start of control.
NB :
The pressure levels and values are given at a transmission hydraulic oil temperature of approximately 50°C.
1) - Mount a 60 bar pressure gauge on to the TH7 braking valve. 2) - Mount a revolution counter on to the engine. 3) - Check the engine idling speed of 750 ±25 rpm.
FIG. 1 :
-Check the height of the inching-brake pedal 05 (dimension A = 70 mm from the bottom of the pedal to the top of the pedal support). -Adjust screw 35. -Tighten the locknut 17.
FIG. 1
FIG. 2 : -Adjust the contactor push rod 37. Dimension B = 18 mm (inching pedal released). -Adjust screw 03 to draw in the push rod to obtain dimension B. -Tighten the locknut 02.
FIG. 3 : -Adjust the braking boss 06. Dimension C = approximately 13 mm (in relation to the TH7 body 16). -Fine down the adjustment to obtain a pressure reading on the gauge of 14 bar (engine idling speed of 750 ±25 rpm). -Tighten the locknut 17.
