BIG BORE XD® Cylinder Assist® Steering Kit - CJ5/CJ7/CJ8 (1980-1986)
BIG BORE XD® Cylinder Assist® Steering Kit - CJ5/CJ7/CJ8 (1980-1986)
Part Number: SK115
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If you’re running lockers, big tires, and hitting rocky trails in your CJ, your factory power steering’s probably working overtime—and it won’t be long before it gives up. PSC’s Cylinder Assist Steering Kit is the upgrade that gives your Jeep the muscle it needs to steer like it should, on or off the trail.
This system boosts your turning force by about 50%, thanks to our Big Bore XD-CJ steering gear that’s been modified for hydraulic assist. You’ll still get that classic CJ road feel—no twitchiness, no oversteer—just smooth, confident control whether you’re crawling or cruising.
This is the same kit we include with our full Cylinder Assist setups, so if you’re replacing worn parts or doing a fresh install, this kit’s got everything you need to get it done right.

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About:
Why you’ll love it
- Turns big tires with ease – no more fighting the wheel
- 50% more steering force without losing road manners
- Complete kit – no guesswork, no missing parts
- Keeps your CJ’s handling predictable and smooth
Tech Info
Heads‑up for installers
If you’re wheeling in intermediate to advanced terrain, we recommend upgrading the pump with a -6 JIC Male Flow Control Valve and matching hose/fitting kit. It helps keep fluid moving efficiently to the gear and cylinder, especially under load.
Tech Tip:
Positive caster helps your steering wheel return to center and improves straight-line stability. For best results with larger tires, we recommend 6–7 degrees of positive caster on your front axle. It’ll help keep your CJ tracking straight and feeling solid at speed.
Fitment
- Jeep CJ5, CJ7, CJ8 (1980–1986)
- Must have factory power steering
Use it with
- Jeep CJ5, CJ7, CJ8 (1980–1986)
- Factory power steering setups
- PSC Remote Reservoir
- PSC FHV-CE Steering Control Unit (optional upgrade)
What’s included
- Big Bore XD-CJ Cylinder Assist Steering Gear
- Complete Pump and Remote Fluid Reservoir Kit
- High-Pressure Hose Assembly
- 1.75" ID × 6.0" Travel Assist Cylinder with Hose Kit
- PSC 715 Power Steering Fluid
Note: This is the same hardware and components included in our full Cylinder Assist Steering Kits. Perfect for replacement or fresh installs.
California Prop 65 Warning
This product can expose you to chemicals including lead and di (2-ethylhexyl) phthalate, which are known to the State of California to cause cancer, birth defects or other reproductive harm.
For more information, go to www.P65Warnings.ca.gov