Parts for your 1991 Mitsubishi Pajero-Power steering pump

1991 Mitsubishi Pajero power-steering pump — what it does and how to look after it

Yes, the 1991 Mitsubishi Pajero uses a hydraulic power-steering pump. Technical sources that document this include: Mitsubishi Pajero/Montero Factory Service Manual (1991), Group 37A – Power Steering, which details the belt-driven hydraulic pump and steering gear, the Mitsubishi ASA electronic parts catalogue for the V20-series Pajero, which lists the “power steering oil pump” and related hoses/brackets, and general repair manuals such as the Haynes Mitsubishi Montero/Pajero 1983–1997 and Gregory’s Pajero 1983–1996, both of which cover pump removal, fluid specifications, bleeding and belt adjustment.

On a 1991 Pajero, the power-steering pump’s job is to take the grunt out of low-speed manoeuvres and off-road crawling. Driven by the accessory belt, the pump sends pressurised fluid to the steering box so the wheel turns feel light and predictable, even with chunky tyres and a bull bar up front. The system runs automatic transmission fluid (ATF), not generic power-steering fluid, and relies on clean fluid, a healthy belt and tight, leak‑free hoses to keep things quiet and smooth.

As part of regular servicing, it pays to check the reservoir level and fluid condition every oil change. If it’s dark, smells burnt or looks glittery, plan a flush. Use ATF that meets Dexron II/III, mixing fluids can swell seals. Inspect the pump body, shaft seal, clamps and banjo fittings for weeps. A cold-start squeal or chirp often points to a slack or glazed belt, so set the belt tension correctly and replace it if cracked.

Classic warning signs of a tired pump include a whine that rises with engine revs, heavier steering at idle, choppy assist when parking, foamy fluid or metal sparkle in the reservoir. Left alone, contamination can chew out the steering box, so don’t ignore it.

When replacing the pump, swap over the pulley, fit new O-rings/copper washers on the pressure and return lines, and keep everything spotless to avoid grit damage. After refilling, bleed it properly: front wheels off the ground, engine off, turn lock-to-lock slowly, top up, then engine on and repeat until bubbles disappear and the level stabilises. Recheck for leaks after a short drive.

If the shaft is tight and the body isn’t scored, a quality seal kit can be a cost‑effective rebuild. Otherwise, a reman or new unit saves time. For hard off-road or towing, consider a cooler to keep ATF temps in check on hot Aussie and Kiwi days.

• Use ATF meeting Dexron II/III
• Flush fluid every 40–60,000 km or if contaminated
• Check belt condition and tension during each service
• Always bleed the system after hose or pump work

Popular questions about 1991 Mitsubishi Pajero power-steering pumps

What fluid does the 1991 Mitsubishi Pajero power-steering use?
Mitsubishi specifies ATF to Dexron II or Dexron III standards for the Pajero’s power-steering system. Avoid generic “power-steering fluid” unless it explicitly states Dexron compatibility. Mixing fluids can upset seals and cause noise.

How do you bleed the power-steering after replacing the pump?
Raise the front wheels, fill the reservoir with the correct ATF, and with the engine off, turn the steering slowly from lock to lock several times. Top up, then start the engine and repeat until no bubbles appear and the fluid level stabilises. Keep the reservoir topped up throughout to avoid pulling in air.

Does a whining noise mean the pump is done?
Not always. A loose or glazed belt, low fluid level or aerated fluid can all make the system whine. Start by correcting the belt tension and fluid level, and bleed the system. If the noise remains and the steering feels heavy or the fluid shows metallic flecks, the pump may need a rebuild or replacement.