While Nissan’s suspension system will provide many problem-free miles, it’s important that you not take it for granted. From a safety standpoint, it could be argued that the steering and suspension system on any car is the most critical. That’s why it’s so important every car that goes on the lift get a basic safety check. A simple shake, rock and spin of the wheels, along with a good visual inspection, takes only a couple of minutes but will provide huge benefits to both your shop and the customer. You also have the satisfaction of knowing you solved the problem and put the customer in a safer car.
PROFITING FROM MAINTENANCE
It seems everyone is talking about maintenance today. From parts program groups to mass merchandisers, millions are being spent to educate and remind the motoring public about the benefits of proper vehicle maintenance. As import car techs and shop owners, we should be taking advantage of this push for consumer awareness, as well as all the materials offered by our suppliers. We’ve always been aware of the benefits of preventive maintenance, and many of us depend heavily on that work to remain profitable. This makes it even more important that we let every customer know we are willing, and more than able, to handle all their service needs. Signage in the waiting area will help but, more importantly, we have to ask for the work.
With MacPherson strut being the system of choice on Nissan’s line of cars, a simple shake, rock and roll will pick up problems that may go unnoticed by the driver. Grab the wheel at the nine and three o’clock positions and shake it from side-to-side feeling for looseness in the steering system.
If you feel some play, have an assistant look for the movement, concentrating on the inner and outer tie rod ends, side movement of the ball joint, control arm bushings and wheel bearing play. Move your hands to the 12 and six o’clock positions and continue rocking the wheel. Here you’ll pick up play in the strut shaft or mounting, ball joint and control arm bushing. If there was any wheel bearing play in the shake test, it will also be noticeable. Finally, spin the wheel to check for noises and free rotation. Any dragging is probably a result of a brake problem and should be investigated.
If play in the bearing was noticed in a previous check, it should be taken care of whether or not it’s quiet. Check the torque on the axle nut; if it’s loose, you’ll have to make a judgment call. Is it the result of a previous repair, or is the bearing or hub worn? If the play is excessive and the re-torque has no effect, it would pay to be sure a hub is available before the car is disabled on the lift. While it’s not a common problem on Nissans, it’s not unheard of for the hub to show wear on the inner race area, especially in light of the amount of trouble-free miles these cars deliver.
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.
Nissan uses both bolt-in and press-fit ball joints. While the nuts and bolts of replacement will be straightforward, the one tip I can offer is that some time with a wire brush will be well spent. By the time a ball joint wears on one of these cars, it has seen many miles of road salt, and some rust and debris has certainly built up on the hardware. On press-in joints, clean the housing that will be pushed through the control arm to ensure the replacement part fits well. It goes without saying that a lubricant should be used on any undercar hardware or press-fit part.
How your shop is equipped will determine your press-in joint approach. If it’s equipped with a ball joint press, there is no need to remove the lower control arm. If not, you may find it easier to remove the arm to facilitate replacement. Either way, I find it easier to drive the old joint out with the arm attached to the car. With the ball joint separated from the upright, we use a friction lock motorcycle tie-down strap to hold the upright out of the way, paying attention to axle, brake hose and ABS wiring restrictions. After removing the snap ring, clean the area of any rust and road grime. With a support under the control arm, a few sharp shots with a heavy hammer will usually knock the joint out of the arm.
During reinstallation, a controlled push is required to drive the joint home. Do yourself a favor and spend a couple of minutes cleaning the hole in the arm before installing the new joint. Whether you’re using a ball joint press, a hydraulic press or a large vise, be careful that pressure is exerted only on the outside rim of the ball joint housing with the arm supported by the appropriate size tubing or socket. Don’t press on the steel plate that retains the ball in the housing; worst case, this will bind up the joint or, at the least cause, tight clearance in the joint, resulting in premature wear.
The most frequent suspension and steering system-related problems are noise-related, with knocking and squeaking at the top of the list. Other complaints include poor handling, tire wear, drifting or pulling, and vibration issues.
We’ll look at a 2001 Sentra with 120,000 miles that was brought in with a customer complaining of squeaking and knocking noises. We were lucky with this one: A push and lift on the left front wheel well revealed the distinctive up and down “bed spring” squeak. And a quick drive on a road in poor conditions revealed the knock. Our experience told us that this type of squeak is often the result a ball joint or tie rod end that has a damaged boot, which allows the lubricant to escape, and dirt and moisture to get in. The resulting rust tightens up the joint and results in the noise.
The knocking noise sounded like the familiar problem of loose sway bar links or bushings that mount the sway bar to the chassis. This problem is often misdiagnosed; it takes only the slightest amount of play in these components to result in big noises.
If you don’t have a drive-on lift, you’ll be forced to the creeper to confirm the diagnosis. Using a mechanic’s stethoscope, have an assistant push on the fender as you confirm the source of the noise. If you suspect the tie rod end, a twist of the rod should result in the same noise. This is where our good luck escaped; although we could duplicate the noise, we couldn’t really pinpoint the source.
The knocking noise also presented challenges. After hearing it on the road test, I was surprised we couldn’t duplicate this noise using the same push-and-lift technique that revealed the squeak. We looked closely for any free movement in the suspension, paying particular attention to the sway bar mounts and the links. We didn’t see any, so our search for the knock continued back on the frame contact lift. Using pry bars, we again tried to move the sway bar and its links, as well as the lower control arm bushings, but still couldn’t find any movement.
We looked at the bolts that mount the subframe to the unibody, keeping an eye out for rust around the bolts since it’s a dead giveaway that movement is taking place. But we didn’t find anything there either.
At this point, we replaced the suspected lower ball joint, planning to confirm the problem as the job progressed. With the joint separated from the knuckle, it moved freely and quietly. But any movement of the control arm confirmed the noise was coming from the bushing. Side movement on the now-unloaded arm revealed a small amount of play at the outside of the same bushing causing the knocking noise. As the arm was removed, the problem was obvious. The bushing had separated and was moving in the bracket. While this is not a common Nissan problem, you can be sure we’ll look more closely at the bushings in the future.
Tire problems will often produce handling problems. If you’re faced with a drifting or pulling complaint, look to the tires first for the cause. It doesn’t take much stagger (difference in circumference) to cause a pull. We use a narrow 10-foot tape that conforms nicely around the tire. In minutes, all four properly inflated tires can be measured, letting you make an educated decision on where to mount them on the car.
The same goes for vibration complaints. The most important thing we need to establish is when the vibration occurs, and if it’s a noise or something the customer is feeling. We’ve had many customers complain of a vibration when they’re actually talking about an exhaust shield rattle or the growling noise caused by a bad wheel bearing or cupped tire. Like any other repair, if there is any doubt about the complaint, a road-test with the customer is the best way to assure the right problem is addressed.
We’re all experienced with tracking down steering vibrations and should have no trouble with Nissans. Tire condition has to be considered, especially if rotation service has been ignored; it’s not unusual for cupping to take place on the rear tires. Such uneven wear will often mimic a bad bearing, and will certainly cause a noticeable vibration through the seat. This cupping is often thought to be the result of weak rear struts, but I would hesitate to recommend strut replacement if cupping is the only symptom experienced. A better solution is regular tire rotation. If the struts are showing signs of leakage, or fail the time-honored push test, they should be replaced. But still recommend regular rotation service.
While we’re talking about vibrations, we have to consider the front-drive axles, CV joints and brakes. If the shake changes under load, it’s a safe bet there is a worn inner CV joint. The challenge is determining which side is the offender; it could be both. Since we see this only on high-mileage vehicles, we recommend replacing both axles with quality, rebuilt units.
If the customer reports an intermittent vibration that can’t be pinned down, look for evidence of a sticking brake caliper and the overheating it causes. You would think the driver would smell the overheating brakes, but that isn’t always the case. The vibration, however, will get the attention of anyone. We also have to consider the vibration caused by warped rotors. If we’re at the service counter, a road test with the customer is in order.
Although the Nissan suspension system is very reliable, there are a couple of problems worth noting, both on the popular Pathfinder SUV. They involve the mid-1990 model years. If you’re faced with a complaint that the back of the vehicle is “rocking” from side to side, it’s a pretty accurate description. This condition often shows up at interstate speeds and really gets the driver’s attention. The other is a squeaking noise from the front wheels, not unlike a brake pad sensor. Both will be diagnostic challenges if you’re not armed with the proper information.
The rocking problem is cured with the installation of upgraded rear trailing arm bushings. The challenge is that the bushings don’t look bad and no noise is evident. We’ve seen shocks, springs, tires and driveshafts replaced without success.
For the wheel noise, an updated baffle or dust shield is available to prevent the contact that’s causing the squeak. Since this noise sounds a lot like a brake squeak, and most of us wouldn’t think of contact between shield and the seal, it’s easy to waste some time on this one.
To turn these kinds of jobs into profit-makers, get in the habit of checking your service information as the first step. Check for TSBs, or even more valuable websites such as import-car.com, iatn.net and some of the community sites hosted by parts suppliers. All will let you search for problems and, with almost 50,000 techs on iATN alone, it’s a safe bet that someone has already seen it.