1985-1991 Subaru XT Power Steering Pump: Fixing Whines, Leaks, and Stiff Steering

Compatibility Warning: 1.8L Turbo vs. 2.7L XT6

Symptoms of a Failing Power Steering Pump

When the power steering pump starts to fail, it usually gives clear warning signs. Ignoring them can lead to a complete loss of power assist, making the car very difficult to steer.

• Whining Noise: The most common symptom is a distinct whining or groaning sound that rises and falls with engine RPM. As you rev the engine, the whine gets higher in pitch. This is caused by the pump working harder as it wears out or struggles with low or aerated fluid.
• Groaning When Turning: A loud groan or moan, especially when turning the steering wheel to its full lock position (all the way to the left or right), points to a struggling pump.
• Stiff Steering: If turning the wheel, particularly at parking lot speeds, requires significantly more effort, the pump is likely not providing enough hydraulic pressure. In a total failure, the steering will feel extremely heavy, as if the car has no power steering at all.
• Foamy or Discolored Fluid: Pop the cap on the power steering reservoir. If the fluid looks foamy or bubbly (like a 'strawberry milkshake'), it means air is getting into the system, often through a bad seal or a loose hose connection on the suction side of the pump. The fluid should be reddish (like ATF); if it's dark brown or black, it is old, contaminated, and needs to be flushed.
• Fluid Leaks: Puddles of reddish or oily fluid under the front of your car are a clear sign of a leak. The pump itself can leak from its main shaft seal or housing, but be sure to also check the high-pressure and return hoses connected to it.

Diagnosing the Problem

Before replacing the pump, a few checks can confirm it's the true cause.

1. Check the Fluid Level and Condition: With the engine off, open the reservoir and check the level on the dipstick. If it's low, top it off with the correct fluid and check for leaks. If the fluid is foamy, you likely have an air leak. A very common culprit on older Subarus is a small, hardened O-ring on the power steering pump's suction inlet. Sometimes, just replacing this O-ring can fix aeration and whining issues.
2. Check the Drive Belt: A loose or worn-out accessory belt can slip on the pump's pulley, causing a high-pitched squeal and reducing the pump's effectiveness. Ensure the belt is tight and in good condition.
3. Isolate the Noise: If you hear a whining or grinding noise, carefully use a mechanic's stethoscope or a long screwdriver (with the handle to your ear and the tip on the pump body) to confirm the noise is loudest at the pump, and not coming from another accessory like the alternator.

Buying a Used Power Steering Pump

For a vintage vehicle like the Subaru XT, a quality used OEM pump is often a better choice than a new, unproven aftermarket part. Here’s what to look for:

• Verify Part Numbers: Match the part number from your original pump to the used one if possible. Known compatible part numbers include 31052GA160, 31052GA161, 31052GA201, and 31052GA240.
• Physical Inspection: Look for any signs of leaks, especially around the pulley shaft and where the reservoir mounts to the pump body. The unit should be relatively clean, not caked in old, oily grime.
• Pulley and Ports: Spin the pulley by hand. It should turn smoothly with slight resistance but no grinding, roughness, or wobble. Check the threaded ports for the hydraulic lines to ensure they are not stripped or damaged.
• Source Vehicle Information: While mileage is less critical than condition on a 30+ year-old part, a pump from a lower-mileage, well-maintained vehicle is always preferable. Ask the seller if they know the history of the car it came from.

Rebuild vs. Replace

For the hands-on DIYer, rebuilding the original pump is an option. Seal and rebuild kits are available and can be cost-effective. This involves completely disassembling the pump, cleaning all components, and replacing all seals and O-rings. However, for most people, replacement is the more practical route. A quality remanufactured pump offers a balance of reliability and value, and is a much faster repair.

Cost of Replacement

Prices can vary based on location and part availability. Here are typical cost estimates:

Replacement and System Bleeding Procedure

Replacing the pump is a moderately difficult job that a DIY mechanic can perform in a few hours. The most critical part of the process is properly bleeding the system after installation to remove all air.

Key Replacement Steps:

1. Drain the Fluid: Use a turkey baster or fluid pump to remove as much old fluid as possible from the reservoir. Place a drain pan under the pump to catch spills.
2. Loosen Pulley Bolt: While the drive belt is still on and providing tension, it's a good idea to break the main pulley bolt loose.
3. Remove the Belt: Loosen the alternator or tensioner to slacken the accessory drive belt and slip it off the power steering pump pulley.
4. Disconnect Hoses: Disconnect the high-pressure and low-pressure (return) lines from the pump. Be prepared for more fluid to drain out.
5. Unbolt the Pump: Remove the mounting bolts holding the pump and its bracket to the engine.
6. Swap Components: You will likely need to transfer the pulley and fluid reservoir from your old pump to the new one. Always use the new O-rings and seals that come with the replacement pump or rebuild kit.
7. Installation: Installation is the reverse of removal. Mount the new pump, reconnect the hoses (with new O-rings), and reinstall the drive belt. Do not overtighten the banjo bolt for the high-pressure line; it should be snug.

Critical: Bleeding the Power Steering System

Failure to properly bleed the system is the #1 cause of a noisy or failed replacement pump. Air trapped in the fluid will cause whining and damage the pump's internal components. Do NOT start the engine until you have completed the initial bleeding steps.

1. Raise the front wheels off the ground so they can turn freely.
2. Fill the reservoir with fresh, correct-spec fluid to the 'COLD' mark. Leave the cap off. For the 1.8L Turbo XT, this is typically a Dexron-type Automatic Transmission Fluid (ATF).
3. With the engine OFF, slowly turn the steering wheel from full lock to full lock (all the way left, then all the way right) about 10-15 times. Watch the fluid level in the reservoir; you will likely see bubbles surface. Keep the fluid topped up, never letting the level drop low enough to suck in more air.
4. Once the major bubbles stop, check the fluid level again.
5. Now, start the engine and let it run for only a few seconds, then immediately shut it off. Do not turn the wheel yet. Check the fluid level and top up if it dropped.
6. Start the engine again and let it idle. Slowly turn the wheel lock-to-lock a few more times. Listen for any whining. If you hear noise, there is still air in the system. Let the vehicle sit for a few minutes to allow the air to settle out of the fluid, then repeat.
7. Once the fluid level is stable and the pump is quiet, lower the vehicle, and check the fluid level one last time, topping off to the 'HOT' mark if necessary.