It's a good idea to check your power-steering fluid level during your pre- and post-trip inspections, and replace as needed.

Basic Maintenance

Bill Litosky, the service manager at Bergey’s Mack and Volvo of Franconia, Pa., provided detailed information about how to maintain and troubleshoot the power-steering system.

1. Grease all the mechanical parts of the front suspension and steering system at least every 15,000 miles to keep parts like kingpins from binding. This may require putting the front axle on secure jack stands to take the weight off the wheels — check your owner’s manual. Hard steering is commonly a result of neglect there, not trouble with the power steering.

2. In your pre- or post-trip inspection, check the fluid level. Refill with the fluid recommended on the reservoir, normally Dexron II or Dexron III transmission fluid. Wipe the dipstick cover off, pull the dipstick out and put in fluid until it reaches the upper line. On most reservoirs, there is a filler cap that is larger than the dipstick cover that you remove to pour in the fluid. On some, the filler cap and dipstick are combined.

3. Also inspect all places along the high-pressure supply hoses and low-pressure return hoses, and at their connections, for leaks or corrosion. (High-pressure hoses have SAE screw-on type connectors or quick connectors, while low-pressure hoses have hose clamps.) Make sure the hoses are not rubbing anywhere and that protective coverings are intact. Most Class 8 trucks now have steering pumps driven by the geartrain on the engine. But some medium-duty trucks still use belt-driven pumps. If necessary, check the belt to make sure it is tensioned properly and is not frayed or glazed smooth by slippage. Have hoses, corroded connections, or belts replaced as necessary.

5. Change the filter about once a year, or as recommended.

6. On some reservoirs, you may need to remove the top by rotating it counter-clockwise with a wrench, and then pulling it off. Use a syringe to remove a few ounces of fluid and pour it into a clean glass jar. Inspect if for significant amounts of bright metal or obvious moisture content. If it is contaminated, have the system flushed and the fluid replaced. Replace the filter with a new one. Refasten the filter by tightening the wingnut, or reinstalling the reservoir top with a wrench, using new gaskets.