JD 2020 noisy power steering

[LowerPark]

When I start my 1970 2020, all is good, but as soon as you touch the power steering there is a nasty noise I can barely describe and the pipes on the right of the tractor vibrate. this seems to happen at the start of a turn of the wheel, not all the way through. once the tractor is warm, it goes away. no noises from the other hydraulics. Any ideas?

 

[Ed of all trades]

Just a guess but could it be that the oil drains out and it is getting small bursts of oil until it picks up and pumps a full line of oil? Ed

 

[Tx Jim]

Are line spacers(parts keys 9,22 & 23) in place with clamps? I've seen spacers removed when splitting tractor to repair clutch but not replaced(lazy technician). How long since hyd filter was changed & sump screen(parts key 15) checked?