12k Single Hydraulic Trailer Jack with (Single Double Pump) Kit "Weld On" or "Bolt On"
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We offer the following methods of delivery:
- Same day Freight Shipping when ordered Mon-Fri before 12pm central time. (excluding holidays)
- Pickup from our Mandeville, Louisiana warehouse
- In some cases, free shipping - please contact us: sales@primarymover.com or call 985-888-6554
Primary Mover 12K Hydraulic Trailer Jack Kit (Single Leg – Single Double Dump & Jack Combo)
Need one hydraulic power unit to operate both your single acting dump bed and a double acting hydraulic trailer jack?
The Primary Mover 12K Hydraulic Trailer Jack Kit with our Single Double Hydraulic Power Unit is designed specifically for dump trailers that use a traditional single acting hydraulic cylinder but also need powered extension and retraction of a hydraulic trailer jack.
Instead of adding a second pump, this kit allows one compact hydraulic system to control both functions. The dump bed retains its familiar powered-up and gravity-down operation, while the hydraulic jack receives full double acting control.
Key Features
Dump Bed and Hydraulic Jack Controlled by One Power Unit
The Primary Mover Single Double Hydraulic Power Unit combines a single acting dump circuit and a double acting jack circuit into one complete system. This reduces wiring, saves mounting space, and eliminates the need for a second hydraulic pump.
Dedicated Single Acting Dump Circuit
The main dump circuit uses a large #8 SAE work port for improved oil flow. Pressing the UP button powers the dump cylinder, while pressing DOWN opens the gravity-return circuit and allows hydraulic fluid to return to the reservoir.
- #8 SAE single acting work port
- Powered raise
- Gravity lower
- Protected by an approximately 2,800 PSI relief valve
Dedicated Double Acting Jack Circuit
Two separate #6 SAE work ports control the extension and retraction of the hydraulic trailer jack. This circuit is protected by a secondary relief valve set to approximately 3,200 PSI, allowing the jack to operate independently from the lower-pressure dump circuit.
- Two #6 SAE double acting work ports
- Powered jack extension
- Powered jack retraction
- Protected by an approximately 3,200 PSI relief valve
Primary Mover 12K Hydraulic Trailer Jack
Heavy-duty hydraulic trailer jack designed for dump trailers, equipment trailers, goosenecks, and other demanding trailer applications. The jack uses a double acting hydraulic cylinder and includes a load-holding counterbalance valve to help keep the jack securely positioned.
Load-Holding Counterbalance Valve
The integrated counterbalance valve helps prevent unintended jack movement and provides controlled operation while the trailer is being raised, lowered, loaded, or parked.
20-Foot Four-Button Pendant Remote
Operate both trailer functions from one pendant:
- UP: Raises the dump bed
- DOWN: Lowers the dump bed through gravity return
- IN: Operates one direction of the hydraulic jack
- OUT: Operates the opposite direction of the hydraulic jack
Six-Gallon Steel Hydraulic Reservoir
The included six-gallon steel tank provides the hydraulic fluid capacity needed for most standard dump trailer cylinders and most common telescopic dump trailer applications.
Zinc-Plated Inner Sleeve and Foot
The zinc-plated inner jack tube and foot provide added protection against moisture, road debris, salt, and corrosion.
Heavy-Duty Construction
Built with reinforced steel construction, Grade 8 hardware, and components selected for demanding trailer use.
Mounting Options: Bolt-On or Weld-On
Choose the jack configuration that best matches your trailer.
Review the dimensions shown in the product photos and documentation before selecting the bolt-on version to confirm compatibility with your trailer mounting pattern.
Specifications
- Jack Assembly: Primary Mover 12K-rated hydraulic trailer jack with double acting cylinder and load-holding counterbalance valve
- Jack Stroke: 20 inches
- Jack Construction: 4-inch square painted outer tube with zinc-plated inner sleeve and foot
- Power Unit: Primary Mover Single Double Hydraulic Power Unit
- Hydraulic Reservoir: Six-gallon steel tank
- Dump Circuit: Single acting, powered up and gravity down
- Dump Work Port: #8 SAE
- Dump Circuit Relief: Approximately 2,800 PSI
- Jack Circuit: Double acting, powered in both directions
- Jack Work Ports: Two #6 SAE ports
- Jack Circuit Relief: Approximately 3,200 PSI
- Remote: 20-foot four-button pendant
- Standard Hydraulic Hoses: Two 72-inch hoses with #6 JIC straight and 90-degree fittings
- Optional Hose Upgrade: Two 120-inch hydraulic hoses
- Battery Cables: Two 4-gauge battery cables
- Battery Hold-Down: Rubber battery strap included
- Recommended Hydraulic Fluid: Non-synthetic automatic transmission fluid
- Mounting: Bolt-on or weld-on jack options
What's Included
- Primary Mover Single Double Hydraulic Power Unit
- Six-gallon steel hydraulic reservoir
- Primary Mover 12K-rated double acting hydraulic trailer jack
- Load-holding counterbalance valve
- 20-foot four-button pendant remote
- Two 72-inch hydraulic hoses
- Required hydraulic fittings
- Two 4-gauge battery cables
- Rubber battery hold-down strap
- Installation hardware included with the selected jack configuration
Frequently Asked Questions
What is a Single Double Hydraulic Power Unit?
A Single Double Hydraulic Power Unit combines two different hydraulic functions in one system. The first circuit operates a single acting dump cylinder with powered raise and gravity lower. The second circuit operates a double acting hydraulic trailer jack with powered movement in both directions.
This allows a dump trailer owner to operate both the dump bed and hydraulic jack from one power unit without converting the dump cylinder to a double acting system.
Will this kit work with my existing single acting dump trailer?
Yes. This kit is specifically designed for trailers using a single acting hydraulic dump cylinder. It is a strong upgrade option when replacing an existing single acting power unit or when adding a hydraulic trailer jack to a new trailer build.
Can I use this kit if I already have a hydraulic power unit?
Yes. Many customers use this kit to replace a traditional single acting power unit while adding hydraulic jack functionality. The included Single Double power unit operates both the existing single acting dump cylinder and the new double acting trailer jack, eliminating the need to install a second power unit.
Will this kit work with a telescopic dump trailer cylinder?
Yes. The six-gallon reservoir and single acting dump circuit make this kit suitable for most common telescopic dump trailer applications.
It is commonly appropriate for telescopic cylinders such as 7/90, 7/108, 7/120, and similar applications. Very large telescopic cylinders, including some 12K 144-inch models, may require a larger hydraulic reservoir.
Contact Primary Mover before ordering if you have a 12K 144-inch telescopic cylinder or are unsure of your cylinder's required oil capacity.
Why would I choose the Single Double kit instead of the Dual Double kit?
Choose the Single Double kit when your dump bed uses a single acting hydraulic cylinder and your trailer jack uses a double acting cylinder.
The Dual Double kit is intended for applications where both hydraulic functions require powered movement in both directions. If your dump bed lowers by gravity, the Single Double system is typically the more appropriate and straightforward solution.
Does the dump bed and jack use the same pressure setting?
No. The two functions use separate hydraulic circuits with independent relief protection.
- The single acting dump circuit is protected at approximately 2,800 PSI.
- The double acting jack circuit is protected at approximately 3,200 PSI.
This allows each function to operate at a pressure appropriate for its intended application.
Does the jack extend and retract under hydraulic power?
Yes. The trailer jack uses a double acting hydraulic cylinder. Hydraulic pressure is used to move the jack in both directions.
What is the difference between the bolt-on and weld-on jack?
The hydraulic operation is the same. The difference is how the jack attaches to the trailer.
The bolt-on version uses a specific mounting pattern and should be compared carefully with the dimensions shown in the product photos and documentation. The weld-on version is intended to be welded directly to a properly reinforced trailer frame by a qualified installer.
Are longer hydraulic hoses available?
Yes. The standard kit includes two 72-inch hydraulic hoses. Two 120-inch hoses are available as an optional upgrade for installations requiring additional reach.
What hydraulic fluid should I use?
Primary Mover recommends non-synthetic automatic transmission fluid unless your application, operating environment, or equipment manufacturer requires a different compatible hydraulic fluid.
Why Choose Primary Mover?
- Purpose-Built Hydraulic Solution: Operate a single acting dump bed and double acting hydraulic jack from one power unit.
- Reduced Installation Complexity: One pump, one reservoir, one pendant, and fewer electrical connections.
- Application Support: Our team can help confirm reservoir capacity, hose length, mounting style, and hydraulic compatibility.
- Ships From Our Inventory: No unnecessary dropshipping delays.
- Built for Demanding Trailer Use: Heavy-duty construction, corrosion-resistant components, and proven hydraulic performance.
Upgrade your single acting dump trailer with a complete hydraulic jack system—without adding a second hydraulic power unit. The Primary Mover Single Double Jack Kit combines simple dump-bed operation with full powered jack control in one compact package.
Download: Hydraulic Trailer Jack Manual