Power steering problems

[zukmeista]

Was over at Pouto (big arse sand dunes by dargaville) on boxing day truck went hard in the dunes for most of the day till power steering started making a humming noise and eventually stopped working completely. Fluid was still touching dipstick so shouldn't have been a problem. Swapped pump out with a good secondhand one and new fluid the old fluid was quite dark/dirty. Jacked it up and turned lock to lock a few times to bleed it and put it back on the ground. Still got the same problem. What do I test or replace next? Any help would be much appreciated.

[tweake]

not sure with your vehicle but check the pulley isn't slipping.
a lot of crank pulleys are dampeners and fail causing lack of drive to the belts, especially when you load it up with power steering.

[zukmeista]

Oh shit sorry Daihatsu Rocky 2.8 Turbo. Everything seems to be turning at idle, no belt noise.

[mudlva]

Check ya hoses. Posible return line is either crushed or the excess heat might of delaminated the inner walls

[zukmeista]

The hoses look ok, although one is a bit oily but no obvious leak (doesn't drip oil)

[derk]

its basic hydraulics, it can only be the pump, hoses or steering box, it just about always turns out being the pump mate

[mudlva]

Doesnt mean its getting good flow tho

[zukmeista]

its basic hydraulics, it can only be the pump, hoses or steering box, it just about always turns out being the pump mate

Well I've already changed that...

[derk]

Well I've already changed that...

so that makes it your hoses or steering box then mate but it still usually ends up being the pump

[zukmeista]

Yeah I know but don't wanna chase my tail replacing shit that ain't broke... Any ideas on diagnosing the issue please?

[diogenese]

Pull the return line off the reservoir and plug the inlet. Then run the hose to the top of the res. and run the engine to check flow from the return.
If there is nothing or a dribble then take the high pressure line off the box and run that to the filler and check the flow again. Don't run the pump with no oil, they don't like it!

[zukmeista]

Thanks, I'll give it a go.