HYDRO ASSIST STEERINGUpdated 2 months ago
HYDRO ASSIST STEERING |
What is Hydro-Assist Steering?
In a solid axle vehicle, steering requires force to turn the wheels, especially with large tires, lockers, and during off-road crawling where terrain resistance is high. Hydro-assist is a modification to the power steering system where a hydraulic cylinder (ram assist) is added to support the steering box by pushing or pulling on the tie rod during steering input.
It does not replace the steering box—it assists it. This keeps the system street-legal and road-safe in most states.
Hydro-Assist with Dynatrac Jeep Axles
At Dynatrac, we design axles to be hydro-assist ready. Here's what we recommend:
Axle Model | Recommended Ram Size | Notes |
Dynatrac ProRock 44 | 1.5" bore x 6" stroke ram | Great for 35"–37" tires, tight packaging |
Dynatrac ProRock 60 | 1.75" bore x 6"–8" stroke ram | Ideal for 37"–40" tires |
Dynatrac ProRock XD60 | 1.75"–2" bore x 8" stroke ram | Built for 40"+ tires, heavy use |
ensure the knuckles, steering arms, and axle housing are built strong enough to take the additional side loads that come with a ram pushing on the tie rod.
Pros and Cons: Hydro-Assist vs No Hydro-Assist
Without Hydro-Assist | With Hydro-Assist | |
Steering Effort | Very high with lockers + large tires | Much easier, especially while crawling or aired-down |
System Complexity | Simpler, fewer failure points | Adds complexity—hoses, fittings, ram, tapped box |
On-Road Feel | Retains good road manners | Slightly less road feedback, depends on valve tuning |
Off-Road Control | Can be hard to steer under load | Much more controlled under load or against obstacles |
Component Stress | All torque goes through steering box and pitman arm | Ram shares load, prolongs box life |
Hydro-Assist vs Full Hydraulic Steering
Hydro-Assist | Full Hydro Steering | |
Steering Box | Required | Not used — replaced by orbital valve |
Legal for Highway? | Yes (in most states) | No — no mechanical linkage = not DOT compliant |
Steering Feel | Retains some mechanical feedback | Zero mechanical feedback — feel is “dead” |
Redundancy/Safety | Can still steer if hydraulics fail | Total loss of steering if system fails |
Ideal Use | Dual-purpose rigs, Jeep trail rigs | Rock bouncers, comp crawlers, extreme trail-only rigs |
Installation | Taps into existing box | Requires orbital valve, new pump, reservoir, ram, plumbing |
Steering Speed/Power | Balanced—depends on ram size + box | Can be tuned with double-ended rams for high speed steering |
How it Works (Hydro-Assist)
- Tap the Steering Box: You drill and tap pressure and return ports.
- Install Hydraulic Ram: Connected from axle housing to tie rod.
- Connect Hoses: High-pressure lines run to the steering box taps.
- Upgrade Steering Pump (optional): Many systems need a high-flow pump to keep up.
Dynatrac Recommendations
At Dynatrac, we strongly recommend hydro-assist steering for:
- Any Jeep running 37” tires or larger
- Vehicles with locked differentials front and rear
- Those that routinely wheel in rocks or tight terrain
- Drivers wanting to protect their steering box and extend its life
We also offer axles with high-steer knuckles and flat tops specifically designed to handle the side loads of hydro-assist rams. If you're building a full-on trail rig, our XD60 or ProRock 80 with high-steer knuckles and a 2" double-ended ram can serve as the foundation for transitioning to full hydro later.