Rebuilding a Saginaw Rotary Valve Power Steering Gear

This in-depth HD video provides the steps for working on a Saginaw 700 or 800 series power steering gear. These how-to rebuilding guidelines apply to any Saginaw integral rotary valve power steering gear. Whether a gear needs re-sealing or a complete overhaul, on the work bench or in the field, here are the details!

Many makes of automobiles, light trucks and SUV models use Saginaw rotary valve integral power steering gears. The “700-series”, “800-series” and similar derivative designs, including the “605” gears, each trace back to Saginaw Gear Division’s patented innovation, the recirculating ball-and-nut, worm and sector mechanism. The Rotary Valve design introduced in 1959 took steering gear technology to the next level and survives to this day.


This typical Saginaw 800-series type steering gear is undergoing adjustment on the work bench. Once you have diagnosed a problem with a gear, remove the unit from the vehicle. This gear fits a Jeep YJ Wrangler.

Note: Begin with the in-chassis troubleshooting feature at the magazine, click here. The troubleshooting feature provides guidelines for performing an in-chassis steering gear diagnosis. You can quickly determine the extent of wear or damage to a Saginaw Rotary Valve integral power steering gear before removing the gear for rebuilding or resealing.

When resealing or rebuilding the Saginaw Rotary Valve integral power gear, the parts to be replaced will be similar for the all Saginaw Rotary Valve integral power steering gears. The OEM or aftermarket “complete rebuild kit” will include specific parts for the year, model and casting number of the gear. When identifying a Saginaw gear or ordering parts, be certain to note the year, model and, most importantly, the casting number of the steering gear being serviced.

Here, a Jeep XJ Cherokee gear receives troubleshooting in the chassis.

Here, a Jeep XJ Cherokee Saginaw power gear undergoes troubleshooting in the chassis.

This how-to project’s prototype vehicle is a Jeep® YJ Wrangler. The YJ’s Saginaw power gear shares features and service procedures with other Saginaw Rotary Valve integral power steering gear applications. This includes common dis-assembly steps, inspection procedures and safety concerns that apply when rebuilding any Saginaw rotary valve integral power steering gear built from 1959 onward.

The bore of this Saginaw power steering gear is scored beyond service. An attempt to "hone" a cylinder worn this badly will prove futile.

The bore of this Saginaw power steering gear is scored beyond service. An attempt to “hone” a cylinder worn this badly will prove futile. A new or rebuildable gear housing is required here.

The Jeep® YJ Wrangler gear is the popular four-bolt cover “800 Series” gear design. The procedures shown in this how-to video provide the basic steps and concerns for working on other Saginaw Rotary Valve power steering gears as well. The information proves helpful for rebuilding any Saginaw integral rotary valve power steering gear, including the round sector cover “605” style gear.

When rebuilding a Saginaw 605 gear, refer to the factory service manual service steps and specifications that apply specifically to that gear. This how-to video is in-depth and specific to the common 4-bolt cover (700- and 800-series) gears. Many of these service steps and safety concerns also apply to the 605 gear.

Key distinctions when ordering parts are the power piston bore size and the splined shaft/seal diameters. When setting up a Saginaw integral power steering gear, always use the torque tightening and adjustment specifications for the specific year, make and model vehicle. The casting number on the steering gear housing is a significant identification feature for any Saginaw steering gear.

For additional information on Saginaw power steering and other technical topics, visit the magazine’s forums!



  1. Michael Schweitzer says:

    Hello Moses,
    First, thank you for this wonderful video!

    I’m confused about the orientation of the Torrington thrust bearing and the thrust bearing races. Should the dished side of the thrust bearing races face towards the stub shaft? This is an example of what service references show: What is the correct way to install the two thrust bearing races?

    Thank you for your help!

    • Moses Ludel says:

      Hi, Mike…Thanks for your comments. To clarify, the PDF illustration that you provided with the link to Midwest Steering is correct. (The PDF is valuable for anyone working on the Saginaw 800 Series power gear.) The Torrington thrust bearing is sandwiched between two “conical” (dished) thrust races. The thrust races must both point in the same direction. Dished or cupped sides of the thrust races do face toward the stub shaft…Your comment is much appreciated. To make this more clear, I have edited that section of the video, beginning at approximately 36:50-minutes and continuing through the discussion about the Torrington bearing and thrust races.

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