Power Steering Boxes and Fitting Types for the Ford Bronco

Introduction to Power Steering in the Bronco

The Ford Bronco first introduced power steering in 1973, marking a significant leap in comfort and maneuverability compared to the manual steering systems used previously. This transition greatly enhanced the driving experience, especially for off-road enthusiasts and daily drivers alike.

Factory Steering Boxes: A Historical Overview

1973-1975 Bronco Power Steering Boxes

For Broncos equipped with power steering between 1973 and 1975, the factory installed a steering box with a 6-turn lock-to-lock ratio. This box featured inverted flare fittings for the power steering hoses and a 13/16"-36 spline input shaft. In contrast, manual steering boxes from this era had a ¾"-36 spline input. Despite their advancements, these early power steering boxes often provided a steering feel that was perceived as too light, even in stock form.

1976 and Later Upgrades

In 1976, Ford improved the Bronco's power steering with a 4-turn lock-to-lock steering box. This enhancement significantly reduced the amount of steering input needed to maneuver the vehicle, making it especially beneficial in parking lots and tight spaces. Although these boxes were a popular upgrade for many years, the majority of factory units are now worn out. Additionally, no new parts are currently manufactured for these older boxes, complicating the rebuilding process. While we offer common rebuild components such as bearings, seals, and seal kits, many of the internal hard parts may be out of tolerance.

Upgraded Steering Solutions

TOMS OFFROAD Steering Box (P/N 4610)

For those looking to replace or upgrade their old steering box, the Toms Offroad steering box (P/N 4610) is a notable option. This unit features a 3.75-turn lock-to-lock worm and rack, offering quicker response compared to the factory 4-turn box. It mounts using the three factory frame holes and utilizes the same 13/16"-36 spline input. The box comes with a modern O-ring style hose configuration, but we provide ferrules to adapt the hoses to the factory inverted flare style with the 4610F box. The 4610F serves as a direct replacement for factory units, maintaining similar size and shape while providing a slightly heavier steering feel.

PSC X TOMS OFFROAD Steering Box (P/N 4620)

For a premium option, we offer the PSC X TOMS OFFROAD steering box (P/N 4620). This box starts as the standard TOMS OFFROAD model, which is then sent to PSC for a thorough overhaul. PSC adds ports for ram assist and reassembles the box by hand to enhance steering precision. This model features an aluminum sector shaft cap and input housing, and comes with ram assist ports that are capped if not needed. This steering box uses inverted flare fittings, making it compatible with factory hoses.

We also offer this box as part of a complete kit designed to add ram assist to a Bronco. Ram assist involves attaching a hydraulic ram to the steering linkage to provide additional force for turning large tires, which is particularly useful for off-road applications.

Hose Adapters and Fittings

To facilitate compatibility with modern hose systems, we provide AN hose adapters for steering boxes. AN fittings are widely available and simplify the creation of custom hoses and lines.

• K4611 Kit: Converts O-ring to -06AN fittings, compatible with Toms Offroad’s 3.75-turn and previously sold 3.1-turn boxes.
• 3542 Kit: Converts inverted flare to -06AN fittings, suitable for factory Bronco steering boxes and PSC Toms boxes.

Alternative Steering Boxes

Several alternative steering boxes are available or have been used for Bronco applications:

• 4x4x2 Box: Originating from the factory Ford F150 4x4 steering boxes, these feature a 2WD worm and rack, which makes them suitable for Bronco applications. They are generally robust but rely on used components, so quality can vary. Hoses attach from the bottom passenger side of the input housing, and we do not carry compatible hoses for this model.
• F150 2WD Box: This box mounts inside the frame and features hoses on the bottom of the input housing. It uses a ¾"-36 input shaft spline.
• Borgeson Steering Box: This box employs a unique top seal O-ring fitting and a 11/16"-36 input spline.
• Nissan Box: Though not common, the Nissan box has different input and pitman arm configurations compared to factory Bronco options, and it typically uses an 11/16"-36 input spline.

Conclusion

Whether you're restoring a classic Bronco or upgrading for improved performance, understanding the various power steering box options and fitting types is crucial. From factory original components to modern upgrades, each option offers different benefits to suit your needs and preferences.