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Toyotas

TOYOTA SUSPENSION AND STEERING: LIGHT TRUCK AND SUV APPLICATIONS

edited from an article by Larry Bailly, Import Specialist Contributor, ImportCar Magazine

What can be said about Toyota light trucks and SUVs, except that they are unsurpassed for quality, durability and dependability. Since the early ‘70s, the Toyota line of small trucks has been the standard that the other manufacturers have tried to match. The Toyota line now has grown to include models ranging from short-bed 2WD compacts to full-size, extended cab 4WD models, with many steps in between.

To accomplish a smoother, more-controlled ride, the suspension and steering systems have changed over time from buggy-sprung solid axles to a fully independent torsion bar or coil spring suspension with double-jointed drive axles. The steering, suspension and drive systems on all of the Toyota vehicles are very reliable and durable, but still need routine maintenance to provide long-term dependability.

This article is intended to primarily cover the Toyota Hi-Lux and 4Runner series of trucks for the last 10 to 15 years, however most of the information applies to other models as well.

With the boom in the small truck market, especially in the modification area, there are several steering and suspension problems we see on a regular basis. With the installation of oversized wheels and tires, lift kits and the like, some of the stock pieces are a little overstressed. Even with all the stock stuff, the ball joints, tie rod ends, steering damper and the idler arm take a beating when these vehicles are used for more than just commuting.

STEERING SYSTEM REPAIRS
One of the first places to look for slop in the steering linkage is at the idler arm. By grabbing the right front wheel and moving it side to side, there should be no noticeable vertical movement in the arm. If there is movement, the idler arm needs attention. Because there usually are no lubrication fittings on the OE parts, replacement is the only option. There are many good aftermarket replacements available that do have lube fittings and I do recommend them. If the vehicle has oversized tires or wheels, a heavy-duty replacement is recommended.

Idler arm replacement is very easy on these vehicles, and no different than most other nameplates. Remove the bracket bolts, separate the joint from the crossbar and reverse for installation.

Tie rod ends on these trucks take a beating, especially those equipped with bigger tires. There will always be some movement by compression in the rod ends, as they are spring loaded. If you can compress them by hand, they are bad. If there is any side-to-side movement in the rod ends when moving the wheels, they need to be replaced. The best way to look for side-to-side movement is to have the vehicle on the ground and have someone move the steering wheel while you look at each of the linkage pieces for movement.

For safety sake, do not start the engine to perform this inspection, use the "armstrong" steering system. This visual inspection can also pinpoint ball joint and control arm bushing problems that may not be obvious with the vehicle on the hoist.

Tie rod replacement is routine, but make sure that you keep the thread count on the adjustment sleeves as even as possible to allow proper alignment and component strength. As with all vehicles, make sure that the tie rod ends have free movement in operating position to prevent binding.

We have not seen any common failures of steering gears as these parts seem to be sized for much larger vehicles. We see a lot of these trucks with many hundreds of thousands of miles with the OE rag joints at the column shaft still in good shape. However, all of the steering components need to be occasionally inspected. If these vehicles are used for heavy off-road driving, always look at the mounting points on the frame for cracks. Though not common, any vehicle used under severe conditions can develop stress cracks.

If you get a complaint relating to a "loose" feel in the steering, wander or binding on turns, another place to look is the damper. The stock steering dampers are very durable with the stock tires, but with larger ones they can fail. Obvious fluid leakage is a clear sign that a replacement is needed. If you can easily turn the wheels lock-to-lock by hand with the vehicle on the hoist, the damper is probably bad. With binding complaints, you may need to look closely for damage to the shaft or disconnect it at one end and operate it to find the problem. If the vehicle has larger tires, suggest a heavier duty unit to increase the service life.

With almost all Toyota cars and trucks, we get complaints of noise from the power steering, especially when started cold. You can use either a power steering flushing machine with the cleaning fluid on vehicles with really bad noise and badly discolored fluid. Or for preventive maintenance, just use fresh fluid and flush the system until clean fluid is all that remains. We ‘ve saved many customers the cost of a pump replacement with this service.

BALL JOINTS
We do a lot of lower ball joints on the 4WD Toyota vehicles, especially trucks with the earlier, torsion bar sprung front suspension. Usually the complaints are looseness or wandering, shimmy or unusual wear on the tires. The first diagnostic procedure should be the one mentioned earlier for steering linkage, with the vehicle on the ground. With the vehicle on the hoist, it’s usually pretty easy to see the wear with just slight pressure between the lower control arm and steering knuckle. If there is any side-to-side movement at the lower ball joint, this is an indication that they are bad.

There is an allowance for up and down movement, but only about a maximum of 2mm. There are also specifications for rotational drag for the ball joints, but I don’t believe many customers would OK the diagnosis time needed to perform these tests.

If you are going to replace the ball joints, try to find a replacement that has a lube fitting, unlike the original. I may be a little old-fashioned, but for an off-road vehicle, the ability to actually know there is grease in the ball joint is reassuring. The upper ball joints are not stressed as much as the lowers, and the same inspection criteria applies to them, so we don’t do as many upper joints. Again, if there is any question about the upper joints, save the customer money by doing the upper and lower joints at the same time.

Replacement of the ball joints is very straightforward. Though there are some differences between the torsion bar and coil-over suspensions, the ball joint replacement is basically the same. For the lower joint, pull the lower shock bolt to provide movement for the lower control arm. Disconnecting the sway bar will provide additional working room, but is not mandatory.

Remove the bolts holding the ball joint to the steering knuckle and separate the ball joint from the lower arm with a pickle fork. With the lower joint removed and the upper arm bottomed out on its stops, the upper joint can be removed if there is evidence of slop or binding. Installation is the reverse. Make sure the ball joint bolts are in good shape or replace them. To prevent damage to the lower shock bushing, be sure to lower the vehicle to the ground before final tightening or the bushing will tear.

BUSHINGS
Control arm bushing failure is quite rare on these trucks, with the most common failures coming from oil saturation or improper previous repairs. As noted above, tightening the control arm retaining bolts with the weight off the suspension can tear the bushings, leading to failure. Engine or power steering leaks can damage the bushings over time. Again, the only effective inspection is to observe for movement with weight applied. No movement is allowed.

Although aftermarket bushings may work better in some applications, we have found the stock bushings more than adequate unless damaged. Bushing replacement is the same as with most cars; if you have the proper bushing press tools, it’s pretty straightforward. In some cases, the cost of the proper tools, or severe corrosion and rust, may make arm replacement a better alternative.

Alignment is critical on all vehicles, but with the small truck and SUV-type vehicles it is even more critical. Tires cost more and handling is affected more than with a car. When these vehicles are fitted with oversized tires or wheels, the alignment specs may change considerably. Wider or different offset wheels can cause a lot more deflection in the suspension components that may not be fully adjusted out with normal alignment movement.

Any time suspension or steering components are replaced, the alignment should be checked. I recommend driving the vehicle for a short period after repairs to make sure the new components have "settled" before making final adjustments. For this reason, I make toe measurements before replacing steering components to allow "basic" settings during the test drive. This will also make final adjustments easier by reducing the amount of movement needed for final settings.

These trucks are going to be around for decades to come. I fully expect that some will be daily drivers for well over 30 years. Considering the number of Toyotas on the road, there is a market for repairs that will last for a couple of generations of technicians.

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