Steering System HL730-7, HL740-7, HL757-7, HL760-7, HL770-7A Hyundai wheel loaders

Steering System HL730-7 & HL740-7

EMERGENCY STEERING PUMP (mounted on transmission)

Orbitrol Valve, Priority Valve, Steering pump

Steering Cylinder

Steering pump for Hyundai HL730-7 & HL740-7 wheel loaders

Make                                        Capacity GPM
HL730-7 : David Brown
HL740-7 : David Brown

Pump Access through Cab Floor

Orbitrol Steering Valve HL730-7 & HL740-7

Overload Relief Valve HL730-7 & HL740-7

Priority Valve HL730-7 & HL740-7

Steering Neutral HL740-7 & HL730-7

Left Turn HL730-7 & HL740-7

Right Turn HL730-7 & HL740-7

Steering Circuit HL757-7, HL760-7

Steering Piping HL757-7, HL760-7

Steering  Valve  HL757-7, HL760-7

Steering  Valve 1. NEUTRAL

Steering  Valve 2. STEERING LEFT

Remark - in case of maximum steering (end of stroke): When the main steering relief valve opens, oil at left side of the priority valve will flow over the relief valve towards the tank; this results in bigger force at right side and by consequence the priority is given again to port EF

Cushion Valve HL757-7 & HL760-7

Cushion valve assembly
Check valve: consist of N#5,14,15,and 16
Cushion valve : consist of #2,3,4,5,6 and 7
SPEC - 12.2 kg/cm2 (173.5 psi)
a. Pressure check
Required tool:
- Pressure gauge 50kg/cm2 (600 psi)
- Tee fitting
- Manual operate typehydraulic pump
- Install hydraulic pump and gauge as figure at steering cylinder.
- Remove plug #13 at cushion valve
- Operate pump and check the pressure when oil comes out from #13

b. Adjusting:
- Remove plug #4 and piston #7
- Add shim between spring #3 and piston #2 to increase
SPEC: 12.2 kg/cm2 (173.5 psi)

Function : absorb shock or vibration which is created possibly, when loader travel uneven rough ground or when loader tire hit against rock, stockpile of soil and etc during travel.

1)Install manual hydraulic pump and gauge as figure at steering cylinder.
2)Remove plug No.13 at cushion valve.
3)Operate pump and check the pressure when oil comes out from No.13

Steering Unit HL757-7/ HL760-7

Steering System HL770-7A

1. Main pump
2. Brake & fan pump
5. Steering unit
6. Flow amplifier
9. Steering cylinder
23. Oil cooler
24. Air breather
25. Hydraulic tank
26. Return filter
27. Bypass valve
29. Emergency pump
30. Check valve unit
31. Steering PS, NC (CD39)
32. Emergency steering PS NO (CD40)

Steering Piping HL770-7A Hyundai wheel loader


(1) The emergency steering system can be manually tested. Push the pump motor switch in order to determine if the emergency steering and the emergency steering lamp are functional.
(2) When the switch is pushed, the emergency steering pump motor will run. The emergency steering lamp lights. If the emergency steering lamp does not light, do not operate the machine.
Flow Amplifier HL770-7A

Flow amplifier valve is the integrated steering control valve consisting of following function.
- Prority valve: flow divider for steering circuit and hydraulic circuit depending on operating condition of the wheel loader.
- Relief valve, steering: protection device for steering system component.
- Safety relief valve: Safety device for steering cylinder and piping when the unexpected shock aplied to tire during operation in case of steering function is not used.
- Direction valve: 2 way selector valve controlled by orbitol valve (steering wheel)
- Throttle check valve and amplifier spool: Oil delivery controlling device to enhance smooth steering action when a machine starts to steer left or right.