Inoperable pump: There is usually one cause for a new P/S pump to be inoperable—damage during pulley installation. The pulley, although called press-on, is not to be pressed on—a pulley installation tool must be used. Failure to use the proper installation tool can crack the pump housing and cause the pump to be inoperable.
Pump noise or groan: This is most commonly caused by a restriction or air trapped in the system. Can also be caused by heat buildup. (This would include a loss of assist.)
No power assist after recent system service: This is most commonly caused by fluid contamination causing the pressure bypass valve to stick open resulting in no pump pressure. To fix this, remove the flow valve and ensure the pressure bypass valve moves freely in and out. This can also be caused by a large amount of air trapped in the system.
Hard steering in both directions: This can result from insufficient pump flow/pressure, low P/S fluid level, air trapped in system and excessive heat buildup.
Foamy P/S fluid: This is most often caused by either air trapped in the system or a leak in the return line sucking in air.
Reservoir cap blows off: This is most often caused by an air leak. Air is sucked into the P/S system compressed with the fluid and then expands when it reaches the reservoir causing an unintended pressure buildup in reservoir. CCT