Sometimes, no matter how well you take care of your Corvette, there are certain items that just wear out. The steering box on your Corvette is definitely one of those pieces. Often the steering box lubricant NEVER gets changed – oil breakdown as well as water intrusion can cause a real mess inside permanently wearing the internal components. Follow along as I take an in-depth look on what it takes to restore your Corvette’s steering box to its original condition. This job will take a couple of hours to complete and, of course, you’ll need to keep your basic tools handy. The first thing you will need to do is remove your Corvette’s steering box from the frame mount. Consult your manual for procedures.
01: Remove the three bolts that attach the top cover, then remove the lock nut from the lash adjusting screw. Use a screwdriver to turn the lash-adjusting stud in order to back off the top cover of the Corvette steering box.
02: Once you have the cover off, you can use a brass punch and hammer to drive the Pitman shaft out of the box.
03: Use a punch to remove the lock ring. You do not have to remove the lock ring from the worm gear cover.
04: You can now remove the worm gear cover. As you can see, this box was in very bad shape.
05: Remove the worm gear assembly.
06: Use a punch to remove the plug in the back of the box. Once you have removed the plug, you can drive the bearing race out of the housing. Note that you drive the race out from the outside of the housing.
07: Using a large shaft, drive the Pitman arm shaft bushings out of the housing. Then clean the housing thoroughly.
08: Moving back to the worm gear assembly, remove the two screws that attach the retaining clip to the worm gear.
09: Now remove the metal tubes in the top of the worm gear and separate them. You can now clean these as well because you will be reusing them. Once the tubes are out, you can dump all the ball bearings out of the worm gear assembly. Note how the worm gear goes onto the worm gear shaft. You will need to reassemble this the same way. Now you need to clean all of the parts to remove the old grease.
10: Now you can reassemble the steering box.. First, build the worm gear assembly. In Zip Corvette part# SC-638 (1963-1982 Corvette Steering Box Rebuild Kit), we received 54 ball bearings to go into the worm gear assembly. Place a thick coat of steering box grease (part# SC-601) into one side of each of the metal tubes. Then fully line the tubes with as many ball bearings that will fit, then place the other half of the tube on top of them.
11: Place the worm gear shaft into the worm gear, making sure that you have the angle of the teeth the same way as when you took it apart. Once the shaft is in, place the remaining bearings into the holes of the worm gear. Use a small screwdriver to push them down into the worm gear. Once you have installed all of the bearings, push the tubes into the worm gear and install the retaining strap.
12: Moving to the box, use a race installer to install the new Pitman arm bushings into the box. They need to go in the same depth as the ones you removed. If you can’t remember, then the bushings need to be level with the edge of the box to allow room for the seal to be installed. To make them easier to install, try putting them in your freezer for about an hour.
13: Now you can install the worm gear bearing races and the retaining cover. Make sure you drive them in until they stop. Then install the small seal that also goes into the cover.
14: Apply a fair amount of grease onto the end of the worm gear shaft, then place the bearing on the shaft and grease the outside of the bearing. Install the worm gear assembly into the box, making sure that the bearing fully seats into the race. Then pack grease around the worm gear assembly in the housing. Place the second bearing on the worm gear shaft and install the cover. Tighten the cover enough to remove the play out of the worm gear shaft. You will need to center the worm gear assembly now. First make sure that you have almost four complete turns lock-to-lock (actually closer to 3 3/4 turns). Starting from the lock position, turn the shaft 1 3/4 to 2 turns. This will center the worm gear.
15: Install the Pitman arm shaft. Use your finger to pull the worm gear up toward the top of the box, lightly coat the shaft with grease, and insert it into the box. The teeth on the Pitman arm shaft should mesh with the teeth on the worm gear. If the shaft does not push down into the worm gear teeth, you installed the worm gear backwards and will need to correct it. Once the Pitman arm shaft is installed, you can install the lash-adjusting stud with the shim on it. Use the screwdriver to reinstall the cover (don’t forget the gasket).
16: Set the backlash and preload on the worm gear and Pitman shaft gear with an inch-pound torque wrench. The preload is set by tightening the worm gear cover until you reach the desired settings. You should have between 5- and 7-inch pounds of rolling torque for your preload.
17: To set the backlash, turn the adjusting stud until you reach between 10- and 14-inch pounds of rolling torque when the box is centered. This means that as you rotate the box, it will take 7-inch pounds of torque until you start to get close to where the box is centered, then it should peak around 14-inch pounds and start to decrease as you turn the box past the center. Once you have the correct settings, install the lock nut on the adjusting stud and reinstall the steering box in your Corvette.
Steering Box Rebuild: 1963-1982 Corvette Steering Box Rebuild
Source: Zip Corvette Parts
8067 Fast Lane | Mechanicsville, VA 23111 | (800) 962-9632
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