How to: Maintain power steering

John Baxter | September 01, 2010

Check your lube, fluid, filter, pump


1.   Grease the front suspension and steering system every 15,000 miles or less to keep parts, such as kingpins, from binding. This may require putting the front axle on secure jack stands.



2.  Check steering fluid level in pre- or post-trip inspections. Refill with fluid recommended on the reservoir, normally Dexron II or Dexron III transmission fluid.





3.   Inspect high-pressure supply hoses and low-pressure return hoses and connections for leaks or corrosion. Check for rubbing hoses and make sure protective coverings are intact. Most Class 8 trucks have steering pumps driven by the engine’s geartrain. If necessary, make sure the belt is tensioned properly and not frayed or glazed smooth.



4.  Change the filter annually, or as recommended. This Volvo requires unscrewing the filler cap and the large wingnut underneath, then pulling the filter up and replacing. Refasten the filter by tightening the wingnut, or reinstalling the reservoir top with a wrench, using new gaskets.



5.  Inspect the fluid periodically. Use a syringe to transfer a few ounces into a glass jar. Inspect for significant amounts of bright metal or obvious moisture. If contaminated, flush the system by disconnecting the lines to drain them, the pump, steering box and reservoir. Reconnect the hoses. Fill and bleed the system.



6.  If the pump goes bad, you may be able to replace it yourself. The one on this Volvo (green area) is accessible from underneath. Use new gaskets and torque the mounting bolts to the recommended setting. Reconnect the hoses, and fill the reservoir with clean fluid. With the engine running, rotate the steering wheel to expel air. Keep the reservoir full of clean fluid and continue to turn the wheel until the fluid level holds steady.


TROUBLESHOOTING

Hard steering in both directions suggests a worn pump, and hard steering in one direction suggests a bad steering box. When hard steering is not attributable to mechanical parts, find an experienced technician. If the problem is in the steering box, replace with an exchange remanufactured one.

If a hose needs replacement, the standard SAE screw-on fittings will be much easier to install than newer quick disconnects. Screw fittings won’t leak if you turn them tight. Quick-disconnect designs require a special tool. At $50-$75 each, it may be cheaper to replace the hose. n

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