Centralization of P38 steering problem

[bjorn.muellervf]

Whenever I take my hands off the wheel while driving, the wheel seems to want to settle into the 11:45 position, especially when I'm going fast. The vehicle leans slightly to the left when the steering wheel is turned to the 11:45 position. To fix this and get back on the road, I have to set the wheel to 12:00 (or just beyond that, like 12:15). A little resistance from the steering wheel to go back to its "happy" 11:45 position is audible when I do this.

Overall, I'd say that 11:45 is when I feel most at ease with the wheel, and that's also when the car makes its anticipated little left turn. Clearly, I'd like the wheel to come to a stop at twelve o'clock.

After getting four new tires fitted, I can say that the laser alignment is absolutely solid. The steering box's alignment ring feels centred when the wheel is pointed straight ahead. Exactly where the issue is coming from is still a mystery to me.

Some sources have suggested that I try repositioning the drag link or removing the input shaft from the steering box in an effort to make it more central. What should I do? I would appreciate some advice.

[owencastilloss]

It is important to align the pointer on the steering box when the wheels, and not the steering wheel, are facing straight ahead. You can change it using the drag link if that's not the case. You can turn the steering wheel by adjusting the drag link while the wheels are on the ground and the key is in the ignition, without the steering lock on. If you manage to align the rest point with the road ahead, but the wheel is still crooked, you'll have to take it off and spin it until it's perfectly straight. Disconnecting the input shaft is a lot more difficult than this.

[bjorn.muellervf]

I appreciate your response. I proceeded to try out a few different drag link modifications (lengthening, shortening).

Unfortunately, the steering wheel still wanted to return to the 11:45 equilibrium point, and neither adjustment helped. Rather, once the vehicle reached this equilibrium point, the drag link did nothing more than change its direction of travel.

That is to say, even after I played around with the drag link, the car was already turning to the left at 11:45, and the wheel still wanted to settle.

It didn't seem like I could confidently "offest" this equilibrium point by extending or shortening the drag link. Mainly, this is due to the fact that the amount of steering needed to counteract the 11:45 equilibrium point varies marginally with speed. On top of that, I'd rather deal with the underlying issue—the steering wheel's desire to go to 11:45—which has the expected consequence of turning the car left—than use an offset to fix it.

If we want to shift the centering from 11:45 to 12:00, I assume we'll have to tweak the steering box. Could this be a valid assumption?

I'm not entirely sold on that idea unless it's our last resort, because RAVE says it shouldn't be used to fix such a severe discrepancy.

[owencastilloss]

When you center the steering box, the car will settle at straight ahead unless your tracking is extremely off. To make sure the wheels are facing forward as well, you can center the steering box and adjust the drag link. When the steering box is in the center, it doesn't matter which way the wheel is pointing; what matters is that the car steers straight. To make the steering wheel follow straight lines, you must first get the car to go straight while taking your hands off the wheel.

Using a laser alignment rig to do the tracking almost always results in inaccurate results. My own was mounted on one, and it indicated that the rear wheels were three degrees toed in. The mechanic removed the live axle, which makes toe-in on the back wheels mechanically impossible. After reinstalling the sensors, it showed two degrees of toe-out! He finally admitted defeat and told me he was useless. His boss was more traditional, so he instructed me to handle it on my own. To find the distance between the inside of the front wheel rim and the same point on the other wheel, use a laser measure. Make a note of the result. The next step is to repeat the process in front of the wheel rim and take that measurement. The front and rear wheel spacing should be 0.5-1mm wider.

[bjorn.muellervf]

Until I can get in touch with the mechanic who did the tracking, I'm going to have to pretend it's accurate just to keep my sanity. Every farmer, offroader, and truck owner I've met has recommended them as the best 4x4 shop in the area. For the purpose of troubleshooting, I will assume the tracking is at least acceptable until I return it to them. Naturally, I will also try following the directions in the manual that you provided.

In light of the foregoing, I checked to see that the alignment ring was in the center (at least according to my uncalibrated fingers) and that the arrow indicator rested between the two grooves on the steering box when the wheels were directly ahead.

I take it you're advising me to try the drag link again, this time chanting "to hell with the steering wheel"? Put another way, make it drive straight on its own, no matter where you put the wheel. Am I getting that right?

In that case, am I right in thinking that to counteract the leftward pull on my NAS LHD model, I should lengthen the drag link?

[owencastilloss]

It will run straight regardless of the direction the steering wheel is pointing because, yes, extending the drag link will move the wheels to the right. After replacing the ball joints and tires on one of my vehicles, I just finished aligning it from top to bottom. That was extremely off-center, and the new tires' traction caused it to pull in one direction or the other whenever they got the best grip.

Another reason it might pull is if the left-hand brake is binding or if the left-hand tire is underinflated.

Was this always the case, or is this a recent development? If it's something novel, what changed to make it behave that way?

[bjorn.muellervf]

Everything is in order. Expanding the drag link is something I'll look into again. When I last gave it a go, the outcome didn't look promising; however, maybe I was fixated on the steering wheel's location rather than the vehicle's actual tracking. Whatever the case may be, I will update you after I try it again.

Both the tire pressure and the tire age are excellent. I find the theory of brake binding to be intriguing. Could I put this to the test in any way? One thing I can say is that the car brakes with a thud. I would think the pull would be more pronounced when braking if the caliper were malfunctioning, but that is not the case for me.

For years now, I've felt this pull. Since then, I have changed so many things that I am at a loss to determine what may have caused it; however, there was a time when it was absent. There is a consistent pull. At 11:45, it's always to the left.

[omarwalkerah]

When the pistons don't retract correctly or the caliper slide pins become stuck, the brakes won't bind. When braking, it usually has no effect on the pressure of the pads on the disc. This means it can brake evenly when braking, but it binds when cruising.
As a quick test, you can turn both sides of the front axle with a jack, listen for pad noise on the discs, and see if the wheels turn easily. Next, do the same with the backs.

Keep the steering box in the center while you perform the drag link check. If it continues to drive straight, then remove the wheel and center it!

I messed up last year's dash out and put one of mine back on a notch or two out of whack, so it needs fixing.