Faulty power steering

Mine is a low mileage 1987 XJ40. The power steering doesnt operate from cold start (left lock only, the right lock works fine). After 2 or 3 minutes driving the power assist starts working. Before i consider buying a new pump has anyone any suggestions?

Check belt tension and fluid level

Isn’t the early PS driven from a jack shaft?

Who knows? Not I! I have a 94

Very common problem on the early XJ40s. The rack head is aluminum. It took a few years for Jaguar and others to find that the Nylon rings in the head of the rack eat into the aluminum. This causes excessive clearance and no sealing. Once a bit of warmth comes along, the rings soften up and work fine until cold again. This gets worse over time, not better. Along about 1990, Jaguar came out with a revised Adwest rack with harder aluminum. They also came out with “Energized” rings that had a metal expander on the inside instead of plain nylon rings. The cure is a replacement rack. There were companies out there that would steel sleeve the older style racks. Certain ZF racks will also fit, just not sure of the number.

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Hello George and welcome to the forum …

Did the power steering just suddenly start doing this ?

After working on a power steering component and refilling the fluid it’s critical that you properly bleed the system. This is accomplished by going lock to lock with the steering wheel around 25 times. It’s best to raise the front wheels to do this but not absolutely necessary.

The power steering pump is a shaft driven (no belt) impeller design. It either works or doesn’t unless it cavitates because of air in the fluid. That’s why it’s critical to properly bleed the system.

So if the steering was working normally prior to this problem and the fluid was never seriously low (when this happens you can hear the pump cavitate “groan” when you move the steering wheel) then it’s almost certainly a fault within the rack.

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Thanks all for your ideas. I only recently bought her (retirement project) so don’t know how long the problem existed. You have given me lots to ponder. I will start with bleeding the fluid and go from there. Its good to know the PS is shaft driven. I hope it won’t mean a replacement rack.

The power steering systems are self bleeding. Just make sure the reservoir is full to spec. The pump is direct drive (no belt). You mentioned it has assist in one direction so the pump is good. There are 4 rings nylon rings in the rack head that relax over time and they eat a groove into the early XJ40 racks. Replacement of the rack is the answer. Another option is to start the car 5 minutes before you are going to drive it and let it warm up.


George …

Most replacement racks that are available for this car are manufactured by “Adwest”. I have probably gone through half a dozen of them in the 32 years I’ve owned my car. A few years back I purchased a “ZF” rack (a bit more expensive) and so far so good.

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Thanks for further updates everyone.