Ever take a long trip in a vehicle with a steering pull problem? Having to maintain constant pressure on the steering wheel can very tiring, not to mention hard on the tires. A vehicle with a pull problem is a vehicle that is fighting the forces of nature. Something is amiss and is causing the vehicle to follow a path other than a straight one. There are actually several different types of steering pull: a steady pull, a pull that only occurs after turning (memory steer), or a pull that only occurs under certain driving conditions such as bump steer or torque steer. An off-center steering wheel may or may not accompany a pull (which we'll cover shortly). Other times the pull may be more of a "drift" or steering wander to one side or the other. So let's look at some of the common pull-related conditions along with their causes and what you have to do to eliminate them. WHAT CAUSES A STEERING PULL? If your vehicle pulls, drifts or leads to one side while traveling straight, you have a steering pull problem. You may have to maintain steady pressure on the steering wheel to keep your vehicle traveling straight. Possible causes of steering pull include: Uneven Camber Side-to-Side Too much cross-camber can make a vehicle pull or lead towards the side that has the most (positive) camber or away from the side that has the least (negative) camber. The underlying cause may be a bent strut or mislocated strut tower, a bent spindle, collapsed control arm bushing, weak or broken spring, or a shifted crossmember or engine cradle. Check SAI and the included angle to see if these are in or out of specs to diagnose the problem. Also check ride height. Correct by replacing worn or damaged parts, correcting location of strut tower, repositioning engine cradle, and/or reducing cross-camber to half a degree or less by readjusting camber to specifications. Uneven Caster Side-toSside Too much cross-caster can make a vehicle pull or lead towards the side that has the least (negative) caster. The underlying cause may be a bent strut, spindle or mislocated strut tower. Correct by replacing damaged part, correcting location of strut tower, and/or reducing cross-caster to half a degree or less by resetting caster to specifications. Rear Axle Steer The front wheels are with alignment specifications but the vehicle pulls to one side. The underlying cause may be rear toe out of specifications, a bent rear axle, chassis misalignment or a stackup of assembly tolerances in the chassis causing rear axle misalignment. Measure and compare the wheelbase on both sides, check for the presence of a thrust angle, and/or measure individual rear toe. Correct by realigning the rear axle or rear toe, or by performing a thrust angle alignment. Brake Drag Can Cause A Steering Pull The pull is constant to one side and may get worse with the application of the brakes. Raise the vehicle and spin each wheel by hand to check for excessive drag. Possible causes include caliper sticking, frozen or sticking piston in caliper, overfilled fluid reservoir in master cylinder (does not allow caliper pistons to retract when brakes are released), weak drum brake return springs, misadjusted drum brakes, misadjusted parking brake, misadjusted parking brake pedal switch (creates residual pressure in the master cylinder to cause drag). Readjust or repair brakes as required. NOTE: If the pull only occurs when the brakes are applied, the problem may be unequal braking not a dragging caliper or misalignment. The vehicle will pull towards the side with the stronger front brake and away from the side with the weaker or inoperative front brake. Uneven braking can be caused by a sticking floating caliper, a frozen caliper piston, the use of different grades or brands of brake linings side-to-side, fluid leaks, or contaminated linings on one side (by brake fluid or grease). Correct by repairing brakes as required. Other causes may include worn or loose control arm bushings or strut rod bushings that allow alignment changes when braking, so be sure to inspect these components before blaming the brakes. Low or Uneven Tire Pressure Can Cause A Steering Pull The vehicle will lead towards the side with low pressure in the front tire. Correct by inflating tires to recommended pressure. Mismatched Tires Side-to-Side Can Cause A Steering Pull Your vehicle will pull or lead towards the side that offers the greatest rolling resistance. Compare tire sizes, tread wear, tread styles and patterns, also brands. Uneven Tire Wear Can Cause A Steering Pull If one side of the tread is worn more than the other, the tire develops conicity. The effect is much the same as camber, causing the tire to roll towards the side which is worn most. The uneven wear may be the result of incorrect camber, toe and/or failure to rotate the tires periodically to even out wear. If rotating the tires side-to-side reverses the direction of the pull, the tires need to be replaced. A Defective Tire or Ply Steer Can Cause A Steering Pull A manufacturing defect in the way the belts are positioned inside the tire causes the tire to generate a lateral (sideways) force as the tire rolls. To test for this condition, drive the vehicle forward, then in reverse. If the direction of the drift or pull changes, one or more tires at at fault. Rotating the tires front-to-rear or crosswise may help cancel out the ply steer, otherwise tire replacement is necessary to correct the condition. Unbalanced Power Steering Assist Can Cause A Steering Pull Seal leaks in the control valve or off-center steering may route hydraulic pressure into one side or the other of the boost cylinder piston causing the steering to want to turn itself to one side. This can be checked by raising the wheels with the engine running to see if the wheels turn to one side by themselves. No change would indicate another cause, but if the pull suddenly vanishes an imbalance in the power steering system is to blame. The control valve assembly or steering gear needs to be replaced. Miscalibrated Lane Centering Assist or Self-Steering System May Lead To One Side Newer vehicles that have driver assist features such as automatic lane centering or self-steering cruise controls may not steer correctly if the camera system that views the road is not adjusted correctly or the camera alignment is out of specifications. Different vehicles have different calibration procedures, and some require a dealer scan tool to reprogram the system. Changes in wheel alignment can upset the calibration of the camera system. If the steering pull problem started after you had steering or suspension work done, the system likely needs a recalibration to correct the problem. Sometimes a software upgrade from the vehicle manufacturer may be needed to correct the problem. Excessive Road Crown Can Cause Your Vehicle To Lead to The Shoulder of the Road Roads are raised or crowned in the middle so rain water will run off to the outside for proper drainage. But the slight slope to the pavement can often make a vehicle drift to the outside. This can be countered by adding a little positive camber and/or negative caster to the left front wheel , but this should only be done if the vehicle spends most of its time on crowned roads and you have a noticeable pull. MEMORY STEER Can Cause Your Car to Lead to the Left or Right The steering wheel and wheels want to return to some position other than center. This may cause a steering pull or drift to one side after turning. Possible causes include: Misalignment or improper installation of Ford rubber bonded socket (RBS) tie rod ends. RBS tie rod ends do not swivel freely like conventional tie rod ends. When installed, the steering linkage must be centered and straight ahead before the tie rod studs are tightened. Inspect and readjust as needed. Binding in upper strut mounts. Raise wheels and turn the steering from side to side. If effort is high, disconnect tie rod ends from steering arms and turn each wheel by hand to check for resistance. If upper strut mount is binding or loose, the strut will have to removed or rebuilt to replace the upper bearing plate assembly. Binding in steering gear or linkage. Inspect tie rod ends and sockets. Check idler arm bushing. Check rack yoke adjustment or steering play in steering box. Replace or adjust as needed. Binding in ball joints. Unload the ball joints by raising the suspension. Let the suspension hang free with MacPherson struts. Support the lower control arm on an SLA, modified strut or wishbone suspension if the spring is on the lower arm, or the upper arm if the spring is over the upper arm). Turn the wheels from side to side to check steering effort. If high, disconnect the tie rod ends and try again. If a ball joint is binding, replacement is required. Unbalanced power assist. Seal leaks in the control valve or off-center steering may route hydraulic pressure into one side or the other of the boost cylinder piston causing the steering to want to turn itself to one side. This can be checked by raising the wheels with the engine running. If the steering goes to one side all by itself, the control valve assembly or steering gear needs to be replaced. OFF-CENTER STEERING WHEEL IS A SYMPTOM of STEERING MISALIGNMENT This condition may accompany a steady pull or memory steer. But if the steering wheel is off-center (crooked) but there is no pull to either side, possible causes include: Steering linkage not centered when toe was adjusted. Correct by recentering steering wheel and equalizing lengths of both tie rods, then readjusting toe to specifications. Bent steering arm or linkage. Check turning angle both ways. If arm is bent, knuckle (or strut if arm is attached to strut) will have to be replaced. Steering Wheel Not Installed Correctly. An off-center steering wheel may be an indication that the steering wheel has been replaced, or removed possibly to replace an airbag. It was not centered correctly when it was reinstalle…

Fonte: AA1Car.com