Excessive tie rod play is difficult to ignore for any driver. It may start with tire wear on the inner edge of the front tires. Next, there could be a slight knocking during braking or acceleration. Last, tie rod play could manifest itself in a knocking noise while turning.
The No. 1 killer of steering tie rods is damage to the boots. Once a boot is damaged, the joint is contaminated by dirt and debris that can wear the ball and socket. If you see a tie rod end with a damaged boot, recommend replacement of the tie rod. With modern sealed designs, there is no grease fitting, so contaminates cannot be flushed from the joint. Also, some universal replacement boots are not able to properly seal the joint.
The “dry park” method on a drive-on lift is the best method to check for worn tie rods. Tie rod wear on the ball and socket occurs in a defined range of motion. The wear typically occurs in an oval pattern and not a perfect circle. If the suspension is at full droop, the ball and socket may feel like it has no play.
During a dry park test, the inner tie rod ends on steering racks should be tested for excess wear by listening for a knocking or clicking noise as the steering is turned. If the vehicle is on turn plates, have an assistant lock the steering and try to move the tire to detect any play. Whatever the method used, remember that small amounts of wear in each tie rod end can add up to a major variation in toe angle.
Technicians often have a problem locating valid specifications for tie rods. In many cases, a vehicle manufacturer’s warranty tolerances are too liberal for real-world alignment situations. In other cases, a manufacturer simply leaves the issue to the technician’s individual judgment. This allows for the real-world effects that cumulative bushing and ball joint wear will have on the steering and suspension system as a whole.
If you use a pry bar and brute strength, your inspection could be influenced by the bushings in the control arms. If you use a set of “water pump pliers” to compress a tie rod, it will give you a false reading almost every time and is not a measure of wear for some types of tie rods. Even some new tie rods will compress.
Using this method might make it look like you’re doing your proper due diligence for the customer, but it could get you in a load of trouble. Many disreputable shops have used this technique to increase sales, but many repair shop regulators disapprove of this method. Ford and other OEMs recommend technicians use their hands to pull and push on tie rods to feel for play.
Tie Rod Inspection
- Check the outer tie rod ends by grasping BY HAND and push up and down. DO NOT USE A PRY BAR. Check the inner tie rod ends, pushing them front to rear. If any free play is observed in a joint, it is worn and should be replaced.
- While the vehicle is on the ground or on a drive-on hoist, have an assistant rotate the steering wheel rapidly back and forth from 10 o’clock to 10 o’clock while observing the inner and outer tie rods. If the outer tie rod ends have any vertical movement or the inner tie rod ends have any horizontal movement, the tie rod end with the observed movement should be replaced.
- Raise the vehicle and remove the front wheels. The wheels will need to be turned to the right in order to inspect the passenger-side inner tie rod end and to the left to inspect the driver’s-side inner tie rod end. Inspect all four seals for tears, perforations and wear. If there is any indication of wear or perforations on the seal, that tie rod end should be replaced.
- Using a putty knife or other hard, flat, dull object, lift the bottom of the seal up, exposing the stud. If any water escapes from the seal in the form of bubbles or in a liquid form, that tie rod end should be replaced. Closely examine the stud for signs of corrosion, especially around the knuckle. A rag might be needed to clean off any grease on the stud that impairs a good visual inspection. If there is any sign of corrosion, that tie rod end should be replaced.
If you find play at the inner tie rod, confirm that it’s the joint, and not the rack bushings, that are worn. If the rack boot allows it, squeeze the boot to feel that the joint is the problem and the rack isn’t loose and moving in the housing. This will also give you an indication if the rack boot needs to be replaced. It’s always a good practice to replace the boot, but you may find it’s easier to obtain a tie rod end rather than a direct-fit boot. Some of the universals fit well, but if you have to order the tie rod end, add the boot kit to the order.
With outer joints, it’s a good practice to make note of the length of the rod before the end is removed to get the toe in the ballpark on reassembly; many techs simply count the turns when the rod is removed, but a measurement from the center of the joint to a known point is a good back-up. Either way, be sure the toe is within specs before the car is returned.
Chances are you are seeing more aluminum knuckles and suspension components in your shop today. In order to secure the tie rod stud to the knuckle, it requires a different design than the conventional tapered stud. Most aluminum knuckles use Torque-to-Yield (TTY) studs. TTY tie rods are usually installed dry. Do not apply any oil, grease, assembly lube or sealer on the stud or tapered bore. Lubricants increase the torque load on the bolt or stud, which may overload and stretch a TTY bolt too far, causing it to break. If a TTY fastener is over-tightened, it can stretch beyond its limits and break. The increased torque can also cause the female part of the taper to crack if too much clamping force is applied.
Many ball joints may have an initial torque spec as low as 15-30 ft./lbs., and torque angles between 140º and 225º. Never guess or try to use your calibrated elbow. Always look up the spec and use a torque wrench. Make sure the washers on the studs are in good condition and installed in the right direction. If a washer splits or fails, it could cause a catastrophic failure.