Advances in automotive engi-neering have virtually eliminat-ed monthly trips to the lube

rack. However, extended steering/sus-pension inspection intervals and re-duced service requirements havelulled many vehicle owners into afalse sense of security. As a result,many successful shops now bundle athorough steering and suspension sys-tem inspection with the standard“lube, oil and filter” process. You get achance to see your LOF customersonce every 3000 to 7500 miles—makethe most of each visit by inspectingthe steering and suspension system.

Begin by checking the power steer-ing fluid level. If it’s low, there’s ahigh probability of leaks somewherein the power steering system; checkthe hoses, pump seals and the steer-ing gear for obvious leakage. If theodometer shows more than 35,000miles, also carefully inspect the hosesand shaft seal on the pump for slightweepage. Replace any hose that ap-pears brittle, damaged or excessivelyworn (whether it leaks or not).

Don’t forget to inspect the powersteering pump drivebelt, too. Re-member, if the belt breaks at highwayspeed, it can lead to a loss of control,especially in poor road conditions.

Detecting leaks on a rack assemblycan be tricky because the rack endseals are hidden inside the protectiveboots. When you inspect the rack,look at the boots carefully; turn back

the ends at the rack and tie rod andcheck for dampness. If the boots aredamaged, cracked or show othersigns of wear, they’re due for replace-ment. Of course, if you remove theboots for service, inspect the rackseals carefully.

Finally, top off or replenish thepower steering fluid in the reservoir.Don’t assume that one type of fluid isappropriate for all vehicles. Contraryto popular belief, automatic transmis-

sion fluid is not always suitable for usein the steering system. In fact, differ-ent types of fluids are specified forthe transmission and steering systemon more than half the vehicles on theroad. Check and follow the manufac-turer’s specifications whenever youadd or replace power steering fluid.

Rotating the tires and checking in-flation pressure is, hands down, themost important undercar service.Most carmakers and tire manufactur-

68 February 1999

SYSTEM INSPECTION& LUBRICATION

STEERING & SUSPENSIONP

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ers call for tire rotation every 7500 to10,000 miles, and in some cases,every 5000 miles. Unfortunately, tirerotation is one of the most overlookedservices of all.

Furthermore, many tires installedon vehicles are underinflated. “Gas &go” stations are rarely equipped withair compressors, and the typical mo-torist doesn’t know how to use a tirepressure gauge. As tire aspect ratioshave decreased over the years, infla-tion pressures have increased. Untilthe mid ’80s, most passenger carswere equipped with load-range B tiresthat specified a maximum inflation of32 psi. Today, it’s not uncommon toencounter maximum psi ranges in thelow 40s. And tires on many late-modeltrucks specify maximum inflationpressures of 50 psi and higher. Withtoday’s high-pressure tires, follow themanufacturer’s recommendations. If

you choose to go higher than the rec-ommended specs, hold it to no morethan 4 psi—and never exceed themaximum pressure rating.

Ball joints on today’s cars andtrucks generally last longerthan those used 20 years ago.

However, if a vehicle has more than50,000 miles, inspect the ball jointscarefully. Some joints are equippedwith wear indicators that allow you toquickly and easily determine theamount of wear. The indicator is typi-cally located on the bottom plate nearthe grease fitting. If the indicator isflush with or recessed into the hous-ing, the ball joint should be replaced.

Unfortunately, many ball joints donot provide wear indicators. To prop-erly inspect these types of joints,you’ll have to unload them accordingto the manufacturer’s specifications(normally listed with the alignmentspecs). When the lower joint is theone used to carry the weight, you canusually jack under the lower controlarm until the tire clears the ground.If the upper joint bears the weight,jack the vehicle up by the frame.Once the ball joint is unloaded,mount a dial indicator on a controlarm or steering knuckle, then movethe tire with a pry bar to check axialand radial joint movement.

If the vehicle has an upper weight-carrying joint, you’ll probably en-counter a travel limiter and/or bumpstop that prevents the control armfrom hitting the frame. On these ap-plications, you’ll have to use a wedgeto hold the control arm away fromthe frame when testing the ball joint.You may also need a torque wrenchto check the preload specs on somejoints.

When checking a friction balljoint, replace the joint if you detectany significant movement beyond

69February 1999

BALL JOINTS &STEERING LINKAGE

the manufacturer’s specs.The steering linkage also requires

careful inspection. The pitman armattaches the entire steering linkage tothe steering box, and is therefore sub-ject to a great deal of stress. To checkit, raise the vehicle on a rack and turnthe steering wheel back and forth.The pitman arm stud and the rest ofthe steering linkage should movesmoothly as one unit. Replace the pit-man arm if it doesn’t move at thestud. One note here: On some vehi-cles, the pitman arm stud is part ofthe center link, not the pitman arm.

During your functional test of thesteering linkage, also make surethere’s no excessive vertical move-ment in the idler arm assembly. Gen-erally, no more than 1⁄8 inch of move-ment in either direction is allowed.However, consult the OEM specs be-fore condemning the idler arm.

The rubber-bushed socket (RBS)tie-rod ends used by some manufactur-ers during the 1980s and early ’90s re-quire no lubrication. Eventually, vibra-tion and wear and tear cause the rub-ber to break down. Inspect these tie-rod ends closely and move the steeringlinkage back and forth to check forlooseness. Replacing RBS tie-rod endsin the early stages of wear will signifi-cantly lengthen tire tread life.

Inner tie-rod ends on rack & pinionsteering applications cannot be in-spected visually, but they can be ahigh-wear item. On front-drive cars,the inner tie-rod ends suffer torqueloading on acceleration and oppositeshock during braking. To check forthis type of wear, raise the vehicle on arack, grab the tires while an assistantturns the steering wheel back andforth and check and feel for looseness.

Ball joint and steering linkage in-spection requires a careful eye and asolid knowledge of steering and sus-pension system mechanical opera-tion. Educating your customers aboutthe importance of such service willprotect their investment, ensure safedriving and help you build a success-ful business.