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Posted By: OhioSteve Steering wheel alignment via Pitman Arm adjustment? - Mon Feb 17 2020 12:36 AM
Hello,
My 1948 1/2 ton has it's steering wheel turned right about 90 degrees to the right when driving straight.
To fix would I be correct in approaching by following the bellow steps?

1. Turn the wheel far left until it stops, and then far right until it stops again, while counting the turns.
2. mine is 4 turns
3. Center the steering wheel half way at 2 turns to be in the middle of the gear box travel.
4. Take drag-link off pitman arm.
5. take pitman arm nut off, and pull pitman arm off and place back on with drag link so front wheels stay straight.

Appreciate any feed back.
Thanks
Steve
Did you remove the pitman are when you worked on it? Or do you suspect it has been removed? The pitman arm should be centered when the steering gear is in the middle of its throw. Has any of the steering linkage been modified?

Ed
I have never removed the pitman arm, although I just put in a drag-link since the old one was bent a little. I also put in a new tie-rod and ends in. I also upgraded to disk brakes.
Before putting in the new tie-rod and ends in, I measured the distance of the old rod ends (ball to ball).
47 3/8" is what I showed.
I'm pretty sure the Pitman arm has an idiot-proof mounting system, possibly a wide spline that keeps it from being installed in the wrong position. The steering wheel can be removed and reinstalled in any position, however, I believe.
Jerry
In order to properly center the steering gear, you'll need to remove the drag link or the suspension may cause it to stop short in one direction. Likely your steering wheel is installed off center as Jerry mentioned. The sector shaft does have two wider splines (front and rear), so the only way the pitman arm can go on wrong is pointing up, which would be obviously wrong.
Posted By: Joe H Re: Steering wheel alignment via Pitman Arm adjustment? - Mon Feb 17 2020 04:31 PM
1) unhook linkage or pitman arm from gear box
2) adjust gear box per manual ( https://www.flickr.com/photos/advance-design_parts_co/sets/72157632210242370/ ) wrong year I know, but adjustments are the same
3) center gear box, full left to right, back to 1/2 of total turns. You should feel the tight center spot. If not, the gears are worn or the adjustment is still off,
4) center steering wheel on shaft, recheck with total turns then half to center,
5) reattach the linkage.
6) check toe-in adjustment, tape measure and a helper is about all you need, also check air pressure in tires
7) go for test drive, if steering wheel is still off, rotated front tires left to right to rule out tire wear.

Move on to suspension if still not happy with setting,

8) check front and rear bushings on the front leaf springs, they must be tight and in good working order,
9) check center pin on the leaf spring to axle alignment hole, will need to loosen u-bolts ( best to replace u-bolt at this point ),
10) Check front to rear wheelbase on each side to be sure rear axle is aligned to chassis and front axle,
11) check frame for square, measure diagonal from corner to corner
12) measure both axle locations to frame, find a point on each frame rail that is in same location ( mounting hole, bolt hole, rivet ) to be sure axles are where they are suppose to be

If the steering wheel is still offset after all this checking, an adjustable draglink may be needed. My own truck checked out good, put I never could get the wheel straight while driving straight. An adjustable draglink let me dial it dead on straight on a true flat road, it now drives as good as my '03 Toyota. Just a very slight turn on the draglink center bar changes the steering wheel location quite a bit. It doesn't take much error in the steering and suspension to mess up the steering wheel location.

Just don't move the steering to correct the problem, the truck will drive much better with everything centered and adjusted as GM wanted it to be.

I used tie-rod ends and custom made threaded center bar for my draglink. If you have an old center bar ( long bar tie-rods bolt to ) cut off the right hand threaded end, shorten bar and rethread with correct die, you now have an adjustable draglink without much money spent. New, straight shank tie-rod ends bolt right in to the pitman arm and steering arm.

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Posted By: Joe H Re: Steering wheel alignment via Pitman Arm adjustment? - Mon Feb 17 2020 04:40 PM
One more thing you can try, loosen the u-bolts holding the front axle just enough to move axle. Take a couple heavy duty ratchet straps and pull axle forward on both sides, or pull it backwards on both sides. This will insure the alignment pins are seated against the alignment holes. There is some slop in the holes, so by pulling the axle the same way, you eliminate any variances side to side. Or pull one side and teat drive it, you maybe able to center steering with some trial and error.

Joe
Since the length of the drag link isn't adjustable, there's another possibility. That horseshoe-shaped steering arm between the front of the drag link and the left spindle could be bent. Lots of potholes and other road hazards over the past 60+ years can do unseen damage to steering system components. There's a checking procedure for finding bent linkage that involves checking the geometry between the center of the rear axle and the pivot point of the kingpins that's a bit too complicated to describe in a forum post. Very few alignment shops, and even fewer vehicle owners these days have a good understanding of the physics of a straight axle steering/suspension system.
Jerry
Thanks for all the details.
Joe - Appreciate you attachment. Additional background....Since the fall I've taken off front axle and had Sid check and straighten if needed. I had him put new kingpins in and pushing. When I got it back, I put new front springs in, along with new bushings and u-bolts. I also upgraded to CPP front disk, and then put on a new tie-rod and upgraded tie-rod ends. It wasn't until yesterday when eyeballing the toe and alignment that I realized the steering wheel was off.

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Posted By: 52Carl Re: Steering wheel alignment via Pitman Arm adjustment? - Tue Feb 18 2020 02:13 AM
Check to make sure that you have both castor shims in place. Having one side missing the castor shim will throw off the steering wheel.
One other thing, how in the world did the original draglink get bent?
Both caster shims are in place. The other draglink looks like it took a hit straight from below it. It was not only bent but looks like someone hit it with the welder at one time!
The original tie-rod had some curves too. The gas tank looks like it took several shots from stumps over the years. New tank is waiting to go in. The truck spent her life in northern Minnesota, and she was used...

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With a drag link that's bent that much, the steering arm on the knuckle might be bent as well as Jerry suggested. You can check for bent steering arms that connect to the tie rod by moving the steering all the way to each side and measuring the angle of each wheel. An alignment shop should have a table that will check that. Should be one of the basic steps in alignment. Or just find a better set of steering arms.
I'll look into that, but I think I'm good with that part. It does make me curious if after the bent draglink was installed back on, a guy didn't just realize he now had an off steering wheel, and then pulled the wheel off and aligned to compensate... As a result, when I put straight parts on, the wheel then went off from center. I'll know tomorrow after a quick test...MMmm
It's very important that the steering gear is on its "center point" when the wheels are steering straight ahead. Simply getting the steering wheel spokes level doesn't guarantee you won't have some steering wander, as the only place there's zero slack in the steering box is when it's within a very few degrees of steering wheel movement of the center point. Find center by counting turns lock to lock, level the spokes with the splines, adjust the sector preload according to the service manual instructions, lock the steering wheel at dead center, and then go about making the wheels track straight ahead. If they don't do that, something is worn, bent, or assembled incorrectly. Fabricating an adjustable drag link to accomplish that is like giving a brain tumor patient a pain pill to hide his headache- - - - -you're treating the symptom, not the root cause of the problem.
Jerry
Jerry, I think you miss understood> I'm not going to fabricate anything to compensate anything. simply curious about previous compensations by someone else. that's all.
thanks
I was simply mentioning that some people do that- - - - -not that I thought that's what you were suggesting. Unless some sort of radical modification to the original system has been done, like raising or lowering the suspension, installing a dropped axle, or installing wheels with a huge amount of offset or making radical changes in wheel diameter, it shouldn't be necessary to have an adjustable drag link. If the wheels don't end up tracking straight after everything is new and/or properly adjusted, something is bent.
Jerry
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