Power steering keeps droping out and making me crazy

[First Pooy]

This is driving me crazy and time is against me, I picked up my new pooy last week and when i parked on my driveway witch is on a incline over night and the next morning I have no power steering, it is a new pump how new i don't know but she looks brand spanking new and I found out that the guy put it in 2 weeks ago so I thought that it must have air in it still so I gave a heavy bleed and all lines are good with no leaks the first night it was good so I thoughy that is was fixed but today it has failed again it does come back after a while like it is bleeding it's self again but why is it bleeding back over night, I have never heard of this before oh it is a 92 Gq Td42 and it is a Gu power steering pump,are the Gq and Qu pumps different some how?

[the evil twin]

Must be either bypassing or have an air lock in it somewhere.
It is a pretty basic hydraulic system after all, which in itself makes it frustrating when it plays up

[First Pooy]

I have started parking my Patrol up the drive way back wards and so far that is working so my be the the by pass valve is sticking

[Mike02Ti]

They do have a one way valve plunger type of jobbie in them and if that isnt working properly it wont control the flow for high speed/ low speed and could possibly be your issue.
I forget what line it is exactly but from memory its the one that comes out straight up near the top of the pump. When i rebuilt my pump i noticed mine was sticking a bit now and then. cleaned it down so it moved freely and all was good.
Other than that not much else to go wrong with them apart from a bearing and seals

Sent from my SM-G920I using Tapatalk