Tri-Five Manual Steering Box DIY Rebuild With Help From Borgeson

If you own a classic Tri-Five Chevy with a manual steering box, you’ve likely kept it in service for one or more reasons. At one end of the spectrum, it might be a race car and you really don’t need hydraulic assistance. If that’s not it, maybe your ride is restored to factory stock and you don’t want to add that option. Whatever the reason, there really is nothing wrong with “armstrong steering” if it’s in good shape.

Your Tri-Five’s manual steering box has probably performed flawlessly for years. But as you rack up the miles, you have probably started to notice a bit of “wandering” as you drive. It happens, things wear out. You could try to adjust the lash between the worm and sector gears, but most of the time, that only makes things worse.

manual steering box

Not only was our box internal worn resulting in excessive play, someone had actually cut the input shaft.

A Better Rebuild

However, I do have some good news. Thanks to Borgeson Universal Joint, rebuilding your manual Tri-Five steering box is relatively easy and inexpensive using one of the company’s rebuild kits. These are not simply a re-gasket kit that allows you to pull your box apart, clean it, and then reassemble it using the same parts.

manual steering box

The Borgeson rebuild kit is not a gasket set. It contains all the hard parts you need to make your box perform as well as new.

The Borgeson rebuild kits include all of the necessary components to thoroughly rebuild your original Tri-Five manual steering box. In fact, you get a new pitman (output) shaft, either a short or long worm (input) shaft complete with new recirculating ball bearings, input shaft bearings, new bushings, and gaskets. The long input shaft is used for OE-style steering columns while the short input is used for cars with aftermarket steering columns. Whichever you choose, to say this is a complete kit is an understatement.

The Tri-Five kits are available in two ratios (16:1 and 22:1) with your choice of the aforementioned original long input shaft or a shortened input shaft that is designed to be used with aftermarket steering columns.

I have rebuilt engines, transmissions, and rearends in the past, but this is my first foray into rebuilding a manual steering box. The opportunity simply never presented itself until now. I knew it couldn’t be too hard to accomplish and Borgeson has instructions you can follow.

With the cover bolts removed, the pitman shaft can come out If the shaft is not in the center of its travel, it will not come out. With the shaft and cover removed, the preload adjuster can be unthreaded from the cover and removed from the pitman shaft.

I will say, the hardest part of the job was pressing the old pitman shaft bushings out and the new bushings into the housing. Plus, cleaning up the mess after I disassembled the box and cleaned out the years of grease inside was not much fun either. One thing to keep in mind is you will need a couple of specialized tools to do this, and if you do not have a hydraulic press or bearing-race puller you will need to find a friend that does.

Use a screwdriver to loosen the worm bearing adjuster nut so the worm adjuster can be unthreaded from the housing. Once removed, the worm (input) shaft can be removed from the box.

Breaking It Down

Tearing down the box is fairly straightforward, but there are a few things to keep in mind. For starters, you will need to center the box in its travel. When the shaft is centered, it will slide right out. If you do not do this, the pitman shaft will not be able to come out — no matter how big a hammer you use to ultimately destroy the box. With the steering centered in its travel, take off the three bolts holding the top cover in place and pull the cover with the attached pitman shaft out of the box. Next, remove the lock nut from preload adjuster on the side cover and unthread the preload adjuster from the side cover with a screwdriver to remove it from the pitman shaft.

To remove the worm (input) shaft, use a punch in the slots of the big locking nut to loosen it for removal from the worm-bearing adjuster assembly. With the proper socket or a large set of pliers, unscrew the worm bearing adjuster assembly. Once the threaded assembly is out of the way, gently tap on the input shaft of the gearbox to remove the complete worm assembly and upper worm
bearing from the housing.

Once disassembled, the box can be cleaned and painted. The rebuild kit is as complete as you can imagine. In fact, you will also need to press out the old output shaft bushings and install the new ones in place.

Next, use a screwdriver to pry the input shaft seal from the housing and then use a brass drift working evenly around the edge of the upper bearing cup to remove it from the housing. Finally, using a screwdriver, pry up and remove the lower worm bearing retainer from the worm bearing adjuster and then remove the lower worm bearing. and bearing cup with a bearing puller and slide hammer. Now it’s time to clean the housing.

New seals are installed along with the adjuster cap bearing and race. Before sliding the input shaft back into the box, be sure to thoroughly grease the bearing and also give the shaft a light coating of grease.

Since Borgeson sends all new parts, there will be no need to inspect the old parts for wear (if you’re doing this, you already know things are worn out), just throw them away — they are worn out, after all.

The Manual Steering Box Assembly Begins

Reassembly begins by using a 1-inch socket to tap the input shaft seal into the housing until it is fully seated. Then, install (press) the new bearing cup into the worm bearing adjuster and grease the bearing, and put it in place. With the bearing in place, press the lower bearing retainer into position, securely holding the lower bearing in the worm adjuster assembly.

With the input shaft installed and centered in its travel, the end-cap bearing adjuster can be threaded into place. Borgeson recommends adding a liquid thread sealer to the cap before installation to keep any grease from seeping out when the box is in use. Preload is adjusted as such: turn the input shaft all the way to the end of its travel and then turn back a 1/2 turn. With an 11/16 socket and torque wrench on the shaft, tighten the worm adjuster assembly until the torque wrench reads 5 to 8 in.-lbs. Once adjusted, tighten the locking nut onto the adjuster.

Moving on, after installing the upper worm bearing cup, grease the upper worm bearing and slide over the input of the worm assembly. Now you can install the worm shaft and ball nut assembly into steering gear. Be sure the gear teeth are pointed toward the pitman shaft opening in the housing. With the worm gear in place, install and tighten the worm bearing adjuster until it bottoms out. Once it does, loosen one-quarter turn. Before threading the worm bearing adjuster into place, apply a small amount of liquid thread sealer to the threads to keep the grease from seeping out when the box is installed into the car and put to use.

To set the worm assembly pre-load,  turn the input shaft of the worm assembly all the way to the end of its travel and then back 1/2 turn. With a socket and torque wrench on the input shaft, tighten the worm adjuster assembly until the torque wrench reads 5 to 8 in-lbs. Once proper pre-load is achieved, install the large lock nut on to worm adjuster assembly and tighten it using a punch against the edge of the slots.

Now it’s time to install the Pitman shaft into the housing. For starters, using a 1-1/8-inch socket, tap the pitman shaft seal into the housing. Next, install the preload adjuster shim over the threaded adjuster and insert it into the t-slot on the top of the pitman shaft. With the worm gear centered in the housing, lightly grease the pitman shaft and insert it into the housing. Make sure to line the center tooth of the pitman shaft with the center of the worm assembly.

manual steering box

Before installing the adjuster cap, fill the box with no more than 11 oz. of quality grease.

With the pitman shaft installed, fill the box with 11 oz. of lithium complex EP-2 grease (Note: do not use too much grease). Because, when the worm assembly moves back and forth, it generates pressure. This pressure will force grease to escape the box through the seals. With both shafts installed, thread the side cover assembly onto the preload adjuster stud until the cover sits flush against the top of the box. Then install the bolts, securing the side cover to the box.

To properly set over-center preload, back off the adjuster until it stops and then turn it in one full turn. With the steering gear in its centered position, check the torque required to turn the input shaft. Once the correct torque is achieved, tighten the adjuster lock nut.

Proper Preload

Setting proper over-center preload must be done according to certain guidelines. Begin by backing off (threading out) the preload adjuster until it stops. Once it does, turn it in one full turn. With the steering gear (pitman shaft) in its center position, use a socket that fits the input splines and a torque wrench to check the torque required to turn the input shaft. Remember this reading. Tighten the preload adjuster until the torque required to turn the input shaft through its center position is roughly 4 to 10 in-lbs. higher than your initial torque reading. When proper torque is achieved, install and tighten the preload adjuster lock nut to 25 ft.-lbs. Be sure to hold the preload adjuster so you do not change your setting while tightening the lock nut.

As I previously mentioned, this is not a hard job. So, why drive your classic Chevy with a worn manual steering box. Rebuild it so it’s as good as new and make your Tri-Five more fun to drive. I am not here to tell you that power steering is better than manual steering in any car. However, I will say that if you plan to keep the manual box, why not rebuild it and make it steer like it did when it was new? Thanks to Borgeson, you can do just that.

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About the author

Randy Bolig

Randy Bolig has been working on cars and has been involved in the hobby ever since he bought his first car when he was only 14 years old. His passion for performance got him noticed by many locals, and he began helping them modify their vehicles.
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