Purging hydraulic steering before refill

[SP2]

Just before we were locked back down here in Wales, the Vetus hydraulic steering packed up as a consequence of a parts failure. The new part has been sourced together with Vetus hydraulic fluid to refill the system.

On board the boat there were a selection of hydraulic oils which I assume the last owner had used at some time. Varying viscosities. I am keen to rid the system of this and start afresh.

Any suggestions for a successful outcome?

Thanks in advance, Mike

 

[rogerthebodger]

A strip down of all the components is the only real way to ensure all the old oil is removed.

The biggest danger to hydraulic systems id dirt. swarf or grit in the pipes.

I would just drain all the old oil as much as possible and replace with new. As long as the oil mixes OK the viscosity will be close to correct.

As far as hydraulic systems are concerned a steering system is not very demanding compared with high pressure (5000psi) power systems are concerned.

 

[Bilgediver]

Might want to Flush it rather than purge it and this means using the new oil from the start of the process and being careful not to waste too much. Maybe using the the makers procedure would be a good start which would get the old oil replaced by the new. Just try and catch what comes out the other end



https://www.vetus-shop.com/files/Vetus_Filling_Bleeding.pdf

 

[SP2]

Thanks so far. Something to look forward to when we are unlocked.

 

[superheat6k]

When CFC gases were phased out in the 1990's we had to purge out the old oils from fridge systems by a series of oil changes. It was reckoned by the third change the back contamination level is reduced below 5%, and as long as what comes out is clean, clear and bright, I would be less concerned about a minor background level of the old oil.

If you have a powered autohelm pump a good way to flush the system between the hand and electric helm pumps is to have the auto pilot drive the rudder one way whilst you wheel the other, this is also effective for purging air. As hydraulics are a series of dead ends then some draining close to the rams would be needed.

This Vetus manual might also help you ...

Vetus Steering Systems MT30-175.pdf

 

[SP2]

When CFC gases were phased out in the 1990's we had to purge out the old oils from fridge systems by a series of oil changes. It was reckoned by the third change the back contamination level is reduced below 5%, and as long as what comes out is clean, clear and bright, I would be less concerned about a minor background level of the old oil.

If you have a powered autohelm pump a good way to flush the system between the hand and electric helm pumps is to have the auto pilot drive the rudder one way whilst you wheel the other, this is also effective for purging air. As hydraulics are a series of dead ends then some draining close to the rams would be needed.

This Vetus manual might also help you ...

Vetus Steering Systems MT30-175.pdf

Thanks for your steer (!) on this which is helpful.