My wild guess is your strainer is blocked.
Subaru Power Steering Issues
Before replacing or rebuilding the pump, there’s a few things that are easy to do depending on the symptoms.
Including, in no particular order:
Check both accessory belts for wear and or cracked ribs and replace them.
A snapped accessory belt can lunch your engine, when the loose end potentially wraps around the crank pulley suddenly locking it, jumping the timing belt.
Rule of thumb accessory belt tightness is being just able to turn the belt 90’ on its axis at the longest run between pulleys. If you have a tension gauge, the spec is in your FSM workshop manual.
Use the correct procedure to undo and tighten the tensioners: eg undo the lock nut on the pulley *before* adjusting tension and retighten after.
You may need to re-tension the belts a few weeks later.
Replace the low pressure return o-ring, a few bucks from the Subaru parts counter or online, or:
The OEM spring clamps loose tension with time and use.
Use quality Oetiker or Norma screw clamps on the low pressure hose, both ends.
These clamp types have pressed teeth for the worm, making for secure tension under higher clamping loads.
If the low pressure hose is bulging, replace it with OEM or appropriate aftermarket hose.
Check and clean the strainer in the power steering fluid tank, many miss this step and look for faults elsewhere.
This issue causes air bubbles aka aeration in the power steering fluid and is a must to check especially when replacing the power steering fluid.
Quote from CorgiWerks, SME: “A blocked or restricted strainer in the fluid reservior can aso cause "drop-outs" in the power steering, especially in the Gen4 Turbos.
Some models have the strainer in the pump assy. Backflush it with a garden hose then flush/absorb the water with a quart of methylated spirits, reinstall, re-bleed, lock to lock on stands then figure 8’s in parking lot. Source: CorgiWerx SME.
The fluid reservoir in the Gen4 Libertys is at or below power steering pump entry level and the inlet hose needs to go "up-and-over" to get to the PS Pump inlet.
It’s important to ensure that all air is removed from the inlet hose during bleeding the system.
An old suction fitting o-ring or an old, hard and brittle suction home will not seal at the pump properly and air will be sucked in.”
If the power steering fluid is dark and cloudy, not clear cherry red, drop the fluid and bleed the system properly, lock to lock gently on stands, figure 8’s in car park.
To track down hard to find power steering fluid leaks, clean the area thoroughly and use a UV dye and torch kit via eg eBay, to trace the leak source before the affected area becomes inundated with fluid.
If you’re still experiencing power steering issues, or the actual pump itself is leaking, contact @CorgiWerx on FB (Sydney, NSW) for affordable rebuilds.
Otherwise, consult your local power steering specialist.
Here’s a link to your cars FSM workshop manual and parts translation and sourcing FAQ.
All Subaru models and markets are available in the various links:
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