1989 Lexus LS400: Failed Power Steering Pump Repair Guide

This guide outlines the process for replacing a failed power steering pump on the 1989 Lexus LS400. This issue, while not common, can cause a decrease in steering performance and should be handled by someone with mechanical experience.

Tools Needed

• Power Steering Pulley Tool
• Ratchet Set
• Screwdrivers
• Drain Pan
• Fluid Transfer Pump
• Funnel

Part Needed

• Power Steering Pump (Specific to the 1989 Lexus LS400)

Diagnostic Steps

Though it is possible to diagnose a faulty power steering pump through symptoms such as decreased steering performance and hearing a whirring noise, a thorough diagnostic process will eliminate potential issues. This includes checking the power steering fluid levels and ensuring the power steering belt is in good condition and fitted properly. Once these factors have been ruled out, and if the symptoms persist, the power steering pump is likely the cause.

Guide to Replacing the Power Steering Pump

1. Disconnect and isolate the battery.
2. Prepare your drain pan underneath the power steering assembly.
3. Unbolt the power steering pump mounting bolts and remove the pump assembly.
4. Detach the pulley from the pump using a power steering pulley tool.
5. Use the fluid transfer pump to evacuate any remaining fluid in the old pump.
6. Transfer the pulley to the new power steering pump.
7. Reinstall the pump assembly to the vehicle. Tighten the mounting bolts to the manufacturer’s specifications.
8. Reconnect the hoses and overflow tube.
9. Refill the power steering fluid reservoir and with the recommended fluid.
10. Replace and tighten the cap of the power steering fluid reservoir.
11. Reconnect the battery, start the engine and turn the steering wheel lock to lock a few times to circulate the fluid.

Potential Pitfalls

• Over-torquing the pump mounting bolts can result in damage to the pump assembly.
• Forgetting to prime the new power steering pump may result in a noisy operation or premature pump failure.

Tips for a Successful Repair

• Always use a Lexus-approved power steering fluid for optimum performance and to avoid potential damage to the pump seals.
• Be sure to properly install the power steering belt after installing the new pump.

We hope this guide is of value to you. As always, if the problem persists after your repair attempt, it might be best to consult with a professional mechanic.