I have a 93 f-150, 4x4. Recently when turning either right or left, it will not come back to center, you have to turn it back manually, not too much force, but if you don't you'll keep tuning in that direction. Has power steering, auto. Wondering what it could be, ball joints, tie rods etc.?

 

maybe your ps pump? i had a similar situation on my 1995 f350, i let it go for a few months then one day it wouldn't turn left at all, then in messing with it the ps line blew, so it had to get towed and the ps pump replace.

 

check your steering box adjustment, it sounds like its too tight.

 

Is castor within spec?

 

While you at it check your tire pressures and tires for signs of abnormal wear indicating front end problems.

 

Tire pressure is excellant advice, I can right away if one of the front tires is low, because it will start pulling that way.

BTW this should be in suspension shouldn't it?

 

It is OK here

 

Pulling and centering are two different symptoms of two different problems.

Of course check your tire pressure and make sure they're the same, but more than likely the alignment is off.

All vehicles have a little bit of toe-out (1/2 to 1-1/2 degrees typically) which is what creates the automatic centering "function" of the steering system. If you don't have tow out, it won't center at all. If the tow-out is different from side to side, it may auto-center some of the way, but not all the way depending on what the values are.

So, you need a front end alignment in my opinion, assuming you want auto-center.

 

I had identical problem, went thru all the trouble shooting on this board. Axle u-joints were my problem. If you have manual hubs, it's easy to check. Jack the wheels up, lock the hub, and spin the tire. Also, turn all the way left/right and try spinning tire. Not as easy with auto hubs, but I noticed that when I was in 4x4, the steering would center itself better than not.
Check the axle u-joints and let us know.

 

Same exact centering issues with mine. Ball joints have been changed. Had two wheel alignments, Changed steering box, then another alignment. Problem still exists. I loosened box and tightened the steering box. no luck. Steering pump is starting to whine pretty good now. Thats next. If you have any luck keep it posted here.

 

My steering pump has whined since I had the truck, about 3 years. Air is at 40#s per side. I heard else where about the u-joints will test tomorrow if I have time. Talked to a mechinac he also recommended the alignment first.

 

Most ford vehicles have power steering pump whine. Generally it's from dirt in the system. That won't affect auto centering, just that it's an irritating noise.

 

A couple of questions. Are the tires the stock sizes, and has the truck had any front end damage in the past that would have affected the steering column alignment and cause it to bind.Check the return hose to the power steering pump for kinks.

 

frederic, I thought most vehicles have a small amount of "toe-in", at least that's what I have checked for for many years, but maybe i've been doing it wrong.

 

FSC - darn good eye. I typed "toe out" yet all along I was thinking "toe in". Talk about a major brain fart. My bad.

Anyway... some explaination:

When a pair of wheels is set so that their leading edges are pointed slightly towards each other, the wheel pair is said to have toe-in. If the leading edges point away from each other, the pair is said to have toe-out. The amount of toe can be expressed in degrees as the angle to which the wheels are out of parallel, or more commonly, as the difference between the track widths as measured at the leading and trailing edges of the tires or wheels. Toe settings affect three major areas of performance: tire wear, straight-line stability and corner entry handling characteristics.

For minimum tire wear and power loss, the wheels on a given axle of a car should point directly ahead when the car is running in a straight line. Excessive toe-in or toe-out causes the tires to scrub, since they are always turned relative to the direction of travel. Too much toe-in causes accelerated wear at the outboard edges of the tires, while too much toe-out causes wear at the inboard edges.

So if minimum tire wear and power loss are achieved with zero toe, why have any toe angles at all? The answer is that toe settings have a major impact on directional stability. The illustrations at right show the mechanisms involved. With the steering wheel centered, toe-in causes the wheels to tend to roll along paths that intersect each other. Under this condition, the wheels are at odds with each other, and no turn results.

When the wheel on one side of the car encounters a disturbance, that wheel is pulled rearward about its steering axis. This action also pulls the other wheel in the same steering direction. If it's a minor disturbance, the disturbed wheel will steer only a small amount, perhaps so that it's rolling straight ahead instead of toed-in slightly. But note that with this slight steering input, the rolling paths of the wheels still don't describe a turn. The wheels have absorbed the irregularity without significantly changing the direction of the vehicle. In this way, toe-in enhances straight-line stability.

If the car is set up with toe-out, however, the front wheels are aligned so that slight disturbances cause the wheel pair to assume rolling directions that do describe a turn. Any minute steering angle beyond the perfectly centered position will cause the inner wheel to steer in a tighter turn radius than the outer wheel. Thus, the car will always be trying to enter a turn, rather than maintaining a straight line of travel. So it's clear that toe-out encourages the initiation of a turn, while toe-in discourages it.

The toe setting on a particular car becomes a tradeoff between the straight-line stability afforded by toe-in and the quick steering response promoted by toe-out. Nobody wants their street car to constantly wander over tar strips-the never-ending steering corrections required would drive anyone batty. But racers are willing to sacrifice a bit of stability on the straightaway for a sharper turn-in to the corners. So street cars are generally set up with toe-in, while race cars are often set up with toe-out.

With four-wheel independent suspension, the toe must also be set at the rear of the car. Toe settings at the rear have essentially the same effect on wear, directional stability and turn-in as they do on the front. However, it is rare to set up a rear-drive race car toed out in the rear, since doing so causes excessive oversteer, particularly when power is applied. Front-wheel-drive race cars, on the other hand, are often set up with a bit of toe-out, as this induces a bit of oversteer to counteract the greater tendency of front-wheel-drive cars to understeer.

Remember also that toe will change slightly from a static situation to a dynamic one. This is is most noticeable on a front-wheel-drive car or independently-suspended rear-drive car. When driving torque is applied to the wheels, they pull themselves forward and try to create toe-in. This is another reason why many front-drivers are set up with toe-out in the front. Likewise, when pushed down the road, a non-driven wheel will tend to toe itself out. This is most noticeable in rear-drive cars.

The amount of toe-in or toe-out dialed into a given car is dependent on the compliance of the suspension and the desired handling characteristics. To improve ride quality, street cars are equipped with relatively soft rubber bushings at their suspension links, and thus the links move a fair amount when they are loaded. Race cars, in contrast, are fitted with steel spherical bearings or very hard urethane, metal or plastic bushings to provide optimum rigidity and control of suspension links. Thus, a street car requires a greater static toe-in than does a race car, so as to avoid the condition wherein bushing compliance allows the wheels to assume a toe-out condition.

It should be noted that in recent years, designers have been using bushing compliance in street cars to their advantage. To maximize transient response, it is desirable to use a little toe-in at the rear to hasten the generation of slip angles and thus cornering forces in the rear tires. By allowing a bit of compliance in the front lateral links of an A-arm type suspension, the rear axle will toe-in when the car enters a hard corner; on a straightaway where no cornering loads are present, the bushings remain undistorted and allow the toe to be set to an angle that enhances tire wear and stability characteristics. Such a design is a type of passive four-wheel steering system.