Steering box rebuild

Technical articles by owners, for owners.
Locked
User avatar
Jimm391730
United States of America
Posts: 1456
Joined: Wed Apr 14, 2004 10:58 pm
Location: Idyllwild, CA

Steering box rebuild

Post by Jimm391730 » Sun May 11, 2014 1:30 am

My truck recently developed a "notch" feel in the steering about 1/3rd of a turn to the left. I ordered a rebuild kit as I assumed that there was something amiss within the worm/wheel of the gears. The hardest part for me was getting the steering wheel off; I had to create a very heavy duty puller and finally got it off. The pitman arm was not quite as difficult, but a good puller is essential. Here's the removed assembly; with the pitman arm and steering wheel gone, it is only six simple bolts:
sDSC03372_zps3ea29955.JPG
sDSC03372_zps3ea29955.JPG (143.05 KiB) Viewed 413 times
Drain the oil from both the steering box (red cap on this unit) and the pitman arm shaft (10mm pipe thread plug) before tipping the unit sideways. Remove the locking nut at the opposite end of the pitman arm. Remove the four bolts that hold the cover, then screw in the adjusting screw to allow the cover to come off.
sDSC03373_zps90c03517.JPG
sDSC03373_zps90c03517.JPG (98.16 KiB) Viewed 413 times
Now you can see how the mechanism works; a worm gear (cut to fit the arc of the pitman arm roller, narrow in the middle but larger in diameter at each end) pushes the pitman arm around. To prevent wear, instead of a sliding fit to the worm, the pitman arm has a roller so there is little wear from use. A gentle tap from a dead blow hammer drives the pitman arm shaft from the housing.
sDSC03374_zps2191e69b.JPG
sDSC03374_zps2191e69b.JPG (88.89 KiB) Viewed 413 times
Remove the four bolts that hold the base of the steering shaft and remove it. Note that there are thin shims between this plate and the steering box; don't damage them, you may need to reuse them. The plate has a hole in the bottom for the horn wire and a tube inside to prevent oil from leaking out the hole; do not bend the tube as you pull it out. You will see the ball bearing race and the center of the shaft. Gently tap the steering shaft out this end but be sure to catch the race and the bearing as the shaft moves:
DSC03377_zpscd485b8c.JPG
DSC03377_zpscd485b8c.JPG (122.1 KiB) Viewed 413 times
Now the steering shaft can be withdrawn. I found my problem in an otherwise pristine looking worm:
sDSC03378_zps05022c78.JPG
sDSC03378_zps05022c78.JPG (81.09 KiB) Viewed 413 times
The rebuilding kit includes new brass bushings for the pitman arm but my assembly was within tolerance so I did not replace them. There is a new oil seal for the pitman arm end of the shaft, a rubber dust/mud shield to protect the oil seal, a new o-ring if you separate the pitman arm shaft housing from the steering gears, and new shims for the steering shaft cover. Installation is the reverse of dissasembly; however you want to adjust the number of shims until the steering shaft is not too tight, not too loose. Use Permatex aviation sealant on and between the shims so to prevent any oil leakage (this cover is down when installed in the truck). Tap the pitman arm in place, then put some sealant on the cover and reinstall it by "unscrewing" the adjustment screw to allow the cover to be replaced. Tighten the cover screws, then tighten the adjusting screw by screwing it IN to tighten the fit between the worm and roller. You should be able to easily twist the steering shaft by hand, then as the fit gets tighter it will get harder to turn. The manual has a spec for how much drag the steering shaft will have when the fit is correct.

I used a scrap piece of wire to help pull the horn wire up through the shaft during replacement in the truck

Then put the bolts back in, fill with oil (both sections use standard gear oil, fill both until full), replace and adjust the turn signal, and get the steering wheel on straight and you're done.
Last edited by Jimm391730 on Fri Sep 01, 2017 11:48 pm, edited 1 time in total.
Jim M.
712W and 710M

Locked