Power steering failure

[Sam123]

I’ve got an issue with my power steering on my 2015 Jumbo with 90k miles. Working absolutely fine, and then all of a sudden just as I was reversing onto my drive it’s failed. Symptoms are intermittent/notchy assistance - goes from no power assistance to some power assistance to full power assistance as you turn the wheel.

It’s the full hydraulic setup with engine driven pump. I’ve checked fluid level and that’s spot on, no leaks anywhere, aux belt is fine and pulley is turning fine, no funny noises from pump. Fault doesn’t disappear after driving.

Does anyone have any ideas? I’m thinking pump, but replacement pump is too expensive to just swap and pray. Has anyone seen this before? I can’t find anything relevant on search,

[Sam123]

I’ve taken a chance and just bought a replacement pump - fingers crossed. Can anyone tell what fluid to use to top up after replacing pump. The manual specifies fluid which is green in colour, but the existing fluid is red. Any ideas?

[blue estate]

I’ve taken a chance and just bought a replacement pump - fingers crossed. Can anyone tell what fluid to use to top up after replacing pump. The manual specifies fluid which is green in colour, but the existing fluid is red. Any ideas?

If red then ATF fluid

[Sam123]

To update on this, the problem was actually the crank pulley failing. This wasn’t really evident until I’d removed the aux belt in prep for doing the power steering pump. The pulley is the inner and outer joined by rubber type, and the rubber had split so the inner could rotate freely of the outer, so I guess that whilst it was still able to turn the alternator and coolant pump the load of the PS pump was too much.