Find the Right Hydraulic Trailer Jack Kit
Answer a few quick questions about your trailer, power unit, and mounting style. We will point you toward the most likely Primary Mover jack setup.
Do you already have a hydraulic power unit?
This is the most important starting point.
What type of power unit do you have?
Single-acting units normally power one direction and gravity-return the other. Double-acting units power both directions.
What should the new power unit operate?
Choose whether the jack will have its own pump or share one power unit with the trailer's dump system.
Which control setup do you want?
Keep the existing pump and use manual circuit selection, or upgrade to one four-button power unit for both functions.
Do you want one jack or two?
How do you want to mount the jack?
Which bolt pattern does your trailer have?
Measure center-to-center, not outside edge to outside edge.
Quick Mounting Guide
Primary Mover Bolt Pattern
5.5" wide × 3.5" tall, center-to-center.
Transition Plate Pattern
Adapts a 5.5" wide × 7.0" tall trailer pattern to the Primary Mover jack pattern.
No Bolt Pattern?
Weld on an adapter plate, then bolt the jack to the plate so it remains removable.
Hydraulic Jack Kit Comparison
| Product Family | Power Unit Included | Works With Existing Pump | Control Style | Best Fit |
|---|---|---|---|---|
| 12K / 24K K Kit | Yes | Not required | 2-button jack remote | Customer needs a complete independent jack system. |
| 12K / 24K ADDS Kit | No | Double-acting pump | Manual selector valve + existing controls | Add jacks to a suitable existing double-acting hydraulic system. |
| Single Double Kit | Yes | Replaces existing unit | 4-button remote | Single-acting hoist plus double-acting jack circuit. The 12K kit is available online; call for a 24K configuration. |
| Dual Double Kit | Yes | Replaces existing unit | 4-button remote | Double-acting dump circuit plus double-acting jack circuit. |
| 12K Jack + X-Block | No | Single-acting pump | Manual selector + X-Block handle | Lowest-cost way to keep a working single-acting pump and add one jack. |
More Information
How do I know whether my power unit is single acting or double acting?
A single-acting dump system normally powers the hoist up and returns oil to the tank while the bed lowers by gravity. A double-acting system powers both directions and normally has two working pressure lines. When uncertain, verify the model number, hose routing, or send Primary Mover clear photos before ordering.
Why will a standard ADDS kit not work with a single-acting pump?
The ADDS selector valve only diverts flow between hydraulic circuits. It does not turn a single-acting power unit into a double-acting power unit. A Primary Mover jack is double acting, so a single-acting pump needs either the X-Block system or a replacement Single Double power unit.
What does the X-Block do?
The X-Block allows a single-acting power unit to operate both directions of a double-acting jack. The main selector valve chooses between the dump function and the jack circuit. The X-Block handle then selects jack direction, and the customer presses the existing UP button to power that direction. A dedicated tank return is required.
What is the difference between a Single Double and Dual Double power unit?
A Single Double has one single-acting circuit for a hoist and one double-acting circuit for the jack. A Dual Double has two double-acting circuits. Both use a four-button remote and eliminate manual circuit switching.
Why do 24K systems use a flow divider?
A dual-jack flow divider/combiner helps split and recombine hydraulic flow so the two jacks move at approximately the same rate. It does not hold the load and does not guarantee perfectly identical position under every loading condition. Each jack's counterbalance valves provide load holding.
Should I choose bolt-on or weld-on?
Bolt-on jacks are easier to remove for service, but the center-to-center bolt pattern must match. Weld-on jacks are better when the trailer lacks a compatible pattern. A weld-on adapter plate gives you the strength of a welded mounting surface while keeping the bolt-on jack removable.
Important installation notes
Verify all current product instructions before installation. On the standard Primary Mover jack, the lifting/extend side must receive the proper high-pressure circuit. Hydraulic hoses must be protected from sharp edges, exhaust heat, moving suspension parts, and brake components. Structural mounting and welding should be completed by qualified personnel.