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We distribute an extensive selection of CLARK FORKLIFT HYDRAULIC PUMP parts for all makes and models. We ship directly from various warehouses located all over North America to provide the fastest shipping at the most affordable prices.

For immediate service, contact us TOLL-FREE at 1-800-210-8170


 Clark Forklift Hydraulic Pump

Proper functioning of Clark forklift’s hydraulic system is necessary to perform lift and tilt operations whenever needed. This article covers the working of lift truck hydraulic pump, how to select a hydraulic pump for your Clark forklift trucks and ways to repair and maintain the same.

Hydraulic System Components

The hydraulic system of Clark lift trucks is made of the following components:

  • Hydraulic oil reservoir
  • Hydraulic return filter
  • Hydraulic suction filter
  • Steering priority valve
  • Hydraulic system oil shut off valve
  • Hydraulic pump
  • Forklift control valve
  • Carriage cylinders
  • Steering cylinder
  • Tilt cylinders
  • Lift cylinders
  • Side shift cylinder
  • Stabilizer cylinders

The lift circuit in the system comprises of: control valve, lift cylinder, velocity fuse, one way restrictor, service port release valve (one in the rod end and one in the piston end), and valve lift section.

The title circuit is made of: control valve, left hand tilt cylinder, right hand tilt cylinder, anti-cavitation valve, one way restrictor, and tilt valve section.

Hydraulic Pump Components and Operation

Following are the various components that together form Clark forklift hydraulic pump:

  • O ring and end cover
  • Backup seal
  • Bearing blocks or bushes
  • Pump body
  • Drive and driven gears
  • Seal
  • O ring and flange
  • Circlip
  • Shaft seal
  • Through bolt

This is how the hydraulic pump works:

  • The hydrostatic pump holds the Clark forklift hydraulic pump in position.
  • A coupling from the truck’s engine flywheel directly drives both the pumps.
  • The drive and driven gears present inside the body of the pump also rotate, and gap between the pump body and the gear teeth is very little.
  • As the gears rotate, oil reaches the inlet port of the hydraulic pump by way of the suction strainer. The oil gets transported around the gears’ exterior amidst the body and the gear teeth, and displaced outside via the outlet port.
  • While oil flow is established by the pump, pressure is created by the circuit loads.
  • The gear teeth mesh under load, creating pressure and an uneven outward loading on the bushes or bearing blocks. In order to create an inward and even loading on the bushes and to establish minimal gap between the bearings and gears, the hydraulic pump comprises of a pressure compensation area.
  • There is an E shaped seal present between the bearing blocks’ exterior and the hydraulic pump body. This enables loading of pressure on the exterior of the bearing blocks, balancing them against the gears when loaded.
  • The bearing blocks thus maintain optimum efficiency even under load.
  • If you wish to increase the service hours of your Clark forklift hydraulic pump, perform regular maintenance of the system filters.

Hydraulic Pump Selection

As there are several different types and makes of forklift hydraulic pumps available in the market today, selecting the right pump for your Clark lift trucks to get optimum performance from your truck’s hydraulic system is definitely not as easy task. Following are the various factors you should take into consideration when selecting a hydraulic pump for your Clark forklift’s hydraulic system.

  • Pressure: Choose a hydraulic pump that will possess a maximum constant design pressure. This will be helpful in terms of safety, even when there is a sudden drop in pressure in the valves, lines and other components, which can reduce the hydraulic system’s performance. However, service life of the hydraulic pump will be extended if it does not function at its maximum pressure level
  • Hydraulic fluid: Hydraulic fluids also play a major role in selecting a hydraulic pump. Certain manufacturers recommend using fluids with high viscosity for their hydraulic pumps due to high clearances amidst parts. So to be clearer, you can contact the supplier to know their recommendation of fluid. For synthetic fluids, you can ask the supplier to recommend an appropriate pump.

o   If you choose hydraulic oil with low viscosity, you will end up increasing the rate of internal leakage in the pump, which will further decrease its efficiency. Also, internal leakage of the whole hydraulic system will increase, reducing its efficiency as well.

o   On the contrary, if viscosity of the oil is very high, the hydraulic pump will not be able to draw fluid, which will result in cavitation, reduction in overall system efficiency and reduced usable power.

  • Cost: By using high system pressures and sizing or matching the hydraulic system components properly, you will be able to reduce the cost associated with the Clark forklift hydraulic pump you choose.
  • Efficiency: Never overlook the overall as well as volumetric efficiency of the hydraulic pump when choosing one for your lift truck. If the volumetric efficiency of a pump is less, so will be its overall efficiency. Inefficiency of the pump or system will generate more heat, which will have to be eliminated to avoid extreme fluid temperatures.

The hydraulic pumps offered by Solid Lift Parts are highly efficient and less costly. We have pumps for all makes and models of lift trucks, and we also provide convenient delivery options.


Additional notes (30-09-2015) - 


Clark Forklift Hydraulic Pump is the most used component in a Clark forklift. It is mostly found in the suspension system, braking system, power steering system, and gear & motor system. To accomplish the operations of lift and tilt, according to the requirements, perfect functioning of Clark Forklift Hydraulic Pumps is very important.


Transmission of the power coming from a prime mover to a hydraulic actuator is a major function of a Clark Forklift Hydraulic Pump. These pumps come of two types- centrifugal and positive displacement pumps.  The centrifugal pump deals with the transfer flow of fluid, which is completely dependent on the outlet pressure; while pressure is the main regulator of the positive displacement pumps.


When the Clark Forklift Hydraulic Pump is held in position by the hydrostatic pump, a coupling moves directly to both of the pumps. As both the drive and driving gears rotate, oil after reaching the inlet port is transferred. Eventually, the circuit loads create a pressure. To settle a minimum gap between the gears and the bearings, a pressure compensation area is there inside the pump. An E-shaped seal moves the pressure to the bearing blocks for balancing them against gears.


If lower viscosity oil is used, it may create leaks in the pump and thus may affect on the performance of the pump. A high viscosity oil may disable the pump to draw fluid, which may end up in cavitation.  The high temperature of the hydraulic fluid, abrasion, fluid leaks and aeration may cause problems in the gears, that may cause harm to the pump. In case of damaged parts, emergency replacement and routine maintenance is very important for improved performance of the forklift trucks.


Solid Lift Parts Inc. is always determined to build up a good relationship bond with our customers. We have all the essential materials, tools and contacts to get the perfect parts for all models and makes of forklift trucks. With our team of highly qualified and trained forklift parts specialists, we ensure the best quality of every single part of different models of a forklift. We always keep our inventory packed and update all the information on our website. For your cost effective business, we assure you with fast delivery & speedy shipping. So, we welcome you to choose Clark Forklift Hydraulic Pumps at a very affordable cost. Contact your parts specialist to choose the best & order us!


Clark Forklift Hydraulic Pump Photos



Parts Books & Service Manuals

*Manuals and parts books are not owned by Solid Lift Parts inc. and are presented for reference purpose only.