Hydraulic steering system capacity?

[JonC]

I’m going to attempt to fit a new autopilot pump this weekend, I want to purge the system of the d fluid, maybe refill  it then flush it again with hydraulic fluid. Does anyone have an idea how much fluid I should expect to drain out? It’s more so I know that I’ve got it all out. 
The boats a little Arvor, the old pump is a 1 litre pump I believe. 

[GPSguru]

23 minutes ago, JonC said:

I’m going to attempt to fit a new autopilot pump this weekend, I want to purge the system of the d fluid, maybe refill  it then flush it again with hydraulic fluid. Does anyone have an idea how much fluid I should expect to drain out? It’s more so I know that I’ve got it all out. 
The boats a little Arvor, the old pump is a 1 litre pump I believe. 

IIRC, about 1L, and 2L if you are flushing through.

Edited September 15, 2022 by GPSguru

[JonC]

2 minutes ago, GPSguru said:

IIRC, about 1L, and 2L if you are flushing through.

Thanks, what would be the best way to purge the ram? Could I suck it out with a fluid extractor or is it likely to just piss out on its own? Ideally I’d like to avoid disturbing as many fittings as I can, hopefully just replace the tails with the ones supplied in the kit .

[GPSguru]

2 hours ago, JonC said:

Thanks, what would be the best way to purge the ram? Could I suck it out with a fluid extractor or is it likely to just piss out on its own? Ideally I’d like to avoid disturbing as many fittings as I can, hopefully just replace the tails with the ones supplied in the kit .

It should just bleed out on its own, like continual bleeding of the system until you think you have changed the fluid.

[Odyssey]

You’ll need about 2l of fluid. 
 

To purge the system you keep turning the wheel backwards and forwards while forcing more in the top. Ideally need 2 people for the bleeding part. Lots of videos on YouTube that explain it well. It’s pretty easy… main issues is not going through enough cycles to fully purge it… some stop as soon as fluid comes out the bleed nipple… but I would suggest you keep going until you are use you’ve got all the air out. Just make sure you catch the excess fluid back into a suitable container. 

[JonC]

2 hours ago, Odyssey said:

You’ll need about 2l of fluid. 
 

To purge the system you keep turning the wheel backwards and forwards while forcing more in the top. Ideally need 2 people for the bleeding part. Lots of videos on YouTube that explain it well. It’s pretty easy… main issues is not going through enough cycles to fully purge it… some stop as soon as fluid comes out the bleed nipple… but I would suggest you keep going until you are use you’ve got all the air out. Just make sure you catch the excess fluid back into a suitable container. 

Thanks, my existing system has bottle jack oil, which is basically the same viscosity as stated in the hand book but I fear it may be different to the specified hydraulic fluid for my new pump so thoroughly flushing the system would probably be b st

[suzook12]

16 minutes ago, JonC said:

Thanks, my existing system has bottle jack oil, which is basically the same viscosity as stated in the hand book but I fear it may be different to the specified hydraulic fluid for my new pump so thoroughly flushing the system would probably be b st

There may well be a bit less lubricity in the bottle jack oil so yeah, stick with the grade for the pump

[JonC]

38 minutes ago, suzook12 said:

There may well be a bit less lubricity in the bottle jack oil so yeah, stick with the grade for the pump

Thanks, I’ll do so.