Home How-to Articles Rebuilding a Saginaw Rotary Valve Power Steering Gear

Rebuilding a Saginaw Rotary Valve Power Steering Gear

by Moses Ludel

Read This Before Working on a Saginaw Rotary Valve Power Steering Gear:

Rebuilding a steering gear requires care and special tools. Resealing and rebuilding a Saginaw Rotary Valve power steering gear can be difficult if you do not have these tools or you lack experience with this kind of work…Rebuilt steering gear assemblies are readily available from a variety of sources, including Cardone, AC-Delco and others. If the reseal or rebuild work shown in this video is more than you care to handle, consider purchasing a rebuild/exchange steering gear from a reputable source…Note that the steering gear shown in this lengthy instructional video is from a 1989 Jeep YJ Wrangler. This gear shares many features with other Saginaw Rotary power steering gears of that era and earlier. However, later model Saginaw units use a different seal configuration and may have other unique features. When rebuilding any steering gear, be certain to use a factory or professional level service manual that covers the specific year, make and model of your vehicle. For a general overview, this video will prove helpful. If you decide that the work takes too much time, skill or tooling, consider purchasing a rebuilt/exchange steering gear assembly from a reputable source.

Note that this 1999 Jeep XJ Cherokee’s Rotary Valve power steering gear sector/pitman shaft uses a different seal layout than the earlier gear depicted in the video. Parts differences are one reason why you need a shop manual for your specific year, make and model vehicle. Follow factory guidelines when working on a Saginaw Rotary Valve power steering gear.

This in-depth HD video provides the general steps for working on a Saginaw 700 or 800 series power steering gear. These guidelines apply to many Saginaw integral rotary valve power steering gears in the 700 or 800 series. Whether a gear needs re-sealing or a complete overhaul, either on the workbench or in the field, the video will prove helpful. A factory-level or professional shop manual for your specific vehicle will provide necessary details and specifications for working on your gear.  Do not attempt this job without a shop manual or instructions related to your year, make and model vehicle.

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 power steering gear technology into the modern era, features that survive to this day.  

Note:  The 605 gear shares some features with the 700 and 800 series steering gears; however, the 605 design, its parts and service steps differ significantly from these other Saginaw integral power gear types. Know your gear type and its features.  Use a service manual that covers your specific gear’s design and application.


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 1989 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!

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Michael Schweitzer April 7, 2019 - 7:59 am

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: https://www.midweststeering.com/wp-content/uploads/Sag800-Service.pdf. What is the correct way to install the two thrust bearing races?

Thank you for your help!

Moses Ludel April 17, 2019 - 4:23 pm

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.

J. Cordova September 16, 2020 - 6:27 pm

Hi Moses,

I’m rebuilding a GM Saginaw 605 the one that comes with the round sector cover “605” style gear with left hand thread to the pitman shaft screw. The cover on my gearbox have damage on the thread, do you know someone supplying this type of cover? Used or new.

Thanks in advance,

Moses Ludel September 17, 2020 - 8:27 am

Hello, Mr. Cordova…One source for this part would be eBay. In the automotive section, there are “NOS” (new old stock or new original stock) parts and used parts listed. I went to eBay Motors and used the search term “Saginaw 605 Gear”. Several rebuilt gears and seal kits came up. I also found a cover; however, the seller notes that the cover is only used on 1955-57 Chevrolet 605 conversions. You could contact that seller for more details on why the 1955-57 Chevy application only: https://www.ebay.com/itm/605-steering-box-aluminum-cover-cap-for-1955-1957-Chevrolet-new-/350978564996. Finding a cover is a matter of the right timing. When I looked, there were currently no used gears listed at eBay, which could change at any time. You could keep checking…A local recycling yard would have this popular gear. Ask for a gear of uncertain condition, just for spare parts. Most yards will sell a higher mileage gear under that condition for much less cost. Craigslist is another possibility. I would get another cover in NOS or good condition. Do not attempt to fix the original cover with any kind of thread repair kit. (Left hand thread kits are nearly impossible to find, anyway.) The cover should be readily available, this was a common steering gear. Here’s a seal kit listed at eBay. There are 1671 specific vehicles (84 pages of listings) that use this 605 kit in the 1970s and 1980s: https://www.ebay.com/itm/Power-Steering-gear-seal-kit-Saginaw-605-Gear-G406/161334900717.


Terry Campbell November 16, 2021 - 11:34 am

I have rebuilt a few Saginaw 800 units I am 74 years old and I learned more than I thought I would from your youtube.com video on rebuilding these units. I have watched way more video’s than I care to think about on the 800 units, always looking to find better ways. I rarely comment on the video’s I watch as they are just average, your video surpasses all the others easily and I had to comment on the GREAT job you did. I could go on and on but I am sure you get my point. P.S. You probably know this but I will mention it just in case, I put the worm gear in the rack and feed the ball bearing in that way. Thanks

Moses Ludel November 16, 2021 - 2:06 pm

Terry, thanks for the valued feedback. As you likely sense, I’m academic in my approach. Early training involved technical courses with curriculum by professionals like William Crouse and Harold Glenn. I’m seventy-two, and our backgrounds reflect that level of technical training. From my earliest work as a light- and medium-duty truck fleet mechanic through my writing career with book approvals and endorsements by Ford SVO, GM Motorsports and Mopar Performance, factory service manuals and engineering guidelines have influenced my work. This step-by-step video reflects those standards…Steering is safety related with no room for error. “Blueprint” rebuilding should be the benchmark…I value your appreciation for this level work.

Best regards,

Moses Ludel

Terry Campbell November 19, 2021 - 5:02 pm

Hi Moses, with your expertise, education and hands on experience I thought you would be a good person to ask this question. Of all the different manufacturers of vehicles that used the 800 series gear box, what tool did they use for setting the worm shaft preload cap adjustments? I have yet to see a tool designed for this task.

Moses Ludel November 20, 2021 - 6:13 am

Hi, Terry…I have some tool solutions from my Saginaw steering gear work. Please join us at the forums and post your question (above). I will share photos of my steering gear tools that work, including one that I made and have used consistently. I’ll furnish directions on how I made the tool. There is a “General Repairs” section at the forums (scroll down the list) that would be optimal for this exchange. The forums are hosted by Invision Power Services, very secure, and the access is at: https://forums.4WDmechanix.com. I’ll watch for your post and look forward to your participation.

Best regards,



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