As Dad drove us to the local auto parts store in his 1971 Corvette, one of the key things I noticed was how well he held the old ‘71 Corvette on the road while we sailed along. Sawing the steering wheel like a lumberjack was something I had to learn once the car was passed down to me. Dad worked for General Motors for 34 years before retiring and was always a DIY kind of guy. He seemed to know how to repair almost anything on his cars, and I guess I inherited his determination to do it myself as well.
I was able to adjust some of the play from the steering, but it was clear the internals had suffered over the past 45 years. The Saginaw steering box was found to be tired and worn, it was time to address the sloppy steering. Flaming River has a kit which combines all new internals, including bushings, so with rebuild kit in-hand, all I had to do was remove the box from the Corvette and get to work.
After the clean-up, I needed to remove the Pitman arm from the shaft. A mid-sized puller worked like a champ for this. On the worm gear end of the steering housing, I removed the bolt from the shaft and pulled the steering shaft coupler, or “rag joint” as some might call it, off the shaft.
Breaking Down The Box
Getting the Saginaw steering box apart was not difficult. All the bolts came right out and using a wrench, I loosened up the lash adjustment screw nut. With my flathead screwdriver, I simply turned the screw clockwise until it bound up, tapped the cover with a rubber dead blow hammer, and turned the screw in a bit more.
Eventually, the cap popped off of the steering box and I was able to turn the lash screw out of the cap, revealing the Pitman shaft. With a few taps on the Pitman shaft, it slipped out of the box fairly easily. Be sure to have plenty of paper towels handy, as the stuff inside that box was nasty, especially after 45 years of use.
There is a locking ring on one end of the housing holding the worm gear in place. A simple punch and hammer will loosen the locking ring. Then, with a large thumb wrench, you can loosen the worm gear cover. I happened to have a coilover shock adjusting wrench that worked very well.
The worm gear will then slide out of the housing. There is a bearing on the inside, opposite of the worm gear; be sure to get it out as well. Also, note the orientation of the worm gear when pulling it out, as it needs to go back in the same way.
After cleaning out the remnants of the old grease, remove the worm gear bearing plug from the housing. Look down inside the housing from the worm gear retaining cover end, you should see the race for the bearing that was on the end of the worm gear. There is a plug that caps-off the end of the housing which needs to be popped out of the housing from the inside. A long punch is great for knocking it out with a few taps.
Now, you can get to the backside of the race inside the case. Again, a small punch and some patience is all that’s needed to tap the race out of the housing through the worm gear area. Looking at the worm gear retaining nut/cover, you will notice a seal on the outside and a race for the bearing on the inside. After a clean-up, remove the seal with a flathead screwdriver or seal remover and then tap the bearing race out from the seal-side of the retaining cover. It was easier to do this with the worm gear retaining cover placed back onto the housing, as it gave me something to hold onto while tapping.
Removing the Pitman shaft bushings from the inside of the housing is a little tricky. Using a slide hammer and an assortment of very tight-tolerance, blind-hole bearing pullers, I was able to get a good grip on the bushing at the Pitman arm end of the housing to drive it out from the opposite end.
The second bushing was a little more-tricky, as I had to “customize” a wrench to help hold the bearing puller while getting it tight in place. From the Pitman arm end of the housing, I was able to tap the bushing out with a brass punch and a hammer. The blind-hole bushing/bearing puller gave me a good grip on the bushing without scarring the bed where the new bushing would be reinstalled.
Going Back Together
Laying everything out really helps you get an idea of the process for installation, and there is a little method to the madness here. The Flaming River rebuild kit came with almost everything I would need to rebuild the steering box. The only item not included in the kit is the bushing that goes in the worm gear adjustment cap for the Pitman shaft. Put the bushings in the freezer when you start the tear-down. By the time you get to the point of install, they will be easier to slip in. Usually a couple of hours should be good.
Using a 12-ton press and a very careful attitude, I was able to get both of the bushings slipped back down into the housing. The toughest part is getting the bushings started straight, but a few light taps with an adapter and hammer started it off just fine. The Pitman shaft end-bushing was pressed in flush with the inner lower lip of the housing, leaving enough room on top for the new Pitman shaft seal. The innermost bushing is also pressed flush or just below the surface of the case, ensuring it clears the Pitman shaft gear.
Installing the new bearing races is a pretty straight forward job. I found a socket that was just a touch smaller in diameter than the race, and used this with the 12-ton press to convince the race back into the worm gear retainer cover and the inner worm gear housing. Both bearing races need to seat all the way into each location so be sure the surface and seating areas are free of debris.
Be sure to install the seal in the Pitman arm end of the housing as well as the worm gear retainer cover. These can be installed using a seal-install tool or a socket that is just a bit smaller than the seating area for the seal. The worm gear cover seal will be more difficult, but it is still not hard to install.
You will also want to install the worm gear end-cap into the steering housing now. I used a little bit of Permatex silicone gasket maker in the lip of the cap seat to ensure a good seal. Gently tap the cap into the seat, then a couple of good taps in the center will dimple it, causing the cap to spread out a little into the housing. This locks the cap in place.
Grease! Your specific manufacturer requirements will dictate the type of grease you should use. I have heard of some actually using 90-weight gear oil, but most will use a high-temp or high-drop-point type of grease in the case. It requires a hi-temp drop-point grease because the housing is right next to the exhaust header.
The rebuild kit comes with the worm gear assembled. Adding grease to the shaft and screwing the shaft back and forth should work grease up into the worm gear. Be sure to add ample amounts of grease to the innermost bearing and slip it onto the end of the worm gear before sliding the worm gear into the housing. This should hold the bearing in place until you get it seated into the new race inside the housing.
Grease the outer end of the worm gear as well and slip the new bearing over the end of the worm gear shaft. Make sure the orientation of the bearing is correct into the new race in the worm gear retainer. Do not tighten the worm gear retainer yet; only a snug fitting is needed until you get the Pitman shaft reinstalled. Be sure to add grease to the gap between the bushings in the housing for the Pitman arm. It will not take much, but something is better than nothing.
Align the worm gear so the center, or middle groove, is in the center of the opening for the Pitman arm shaft. After applying a skim coat of grease to the shaft, slide the shaft into the housing, making sure that the center tooth goes into the center groove on the worm gear. This will give you the best starting point for the steering to turn equal amounts both directions.
Tip: Adding a little electrical tape to the Pitman arm end of the shaft will keep the grooves from cutting the seal when it exits the end of the housing.
The lash adjustment screw has a shim which needs to be installed before it gets screwed into the cover. This shim will slip onto the bolt. The shim as well as the head of the bolt will then slip into the groove in the end of the Pitman arm. Be sure to apply a light coating of grease to aid in reassembly of the cover. Now place the new gasket included with the kit onto the shaft.
The Pitman shaft lash adjustment cover can now be assembled by screwing the lash adjusting screw back into the cover. Typically, it screws all the way out to a stop and then you can install the cover using the three bolts while making sure the gasket is properly aligned. Refer to the factory specifications for proper torque on these bolts. For our cover the manual called for 45 ft-lbs.
So, you now have a completely rebuilt steering housing. The worm gear retaining cap will need to be “preloaded”. Refer to your factory service manual for that specification. For this steering box, we used between 5 to 8 in-lbs of torque when tightening the worm gear retaining cap. Secondly, the Pitman shaft adjustment screw will also need to be tightened until it takes between 4 to 10-in-lbs of force to turn the worm gear. The most resistance should be right in the center of the steering rotation.
Finally, the only thing that did not come in the Flaming River rebuild kit was the Pitman shaft cover bushing. I had to source one myself and found that cutting down another bushing was the solution. Maybe they will consider putting this in the kit as well someday.
We also cleaned the outside of the steering housing again with acetone and sprayed a cast color paint on the housing to help with that old enemy called rust. After that, installation of our newly-refurbished steering box finished the task at hand. That is, until we tackle the leaky, power-steering slave cylinder conundrum next. But that’s a story for another day!