New Volvo SX steering ram works at idle but not high speed.

TwoWheels

Cadet
Joined
Jun 3, 2009
Messages
18
I had a steering leak in my 2006 SX-M that I couldn't find, but I was getting air buildup in the fluid reservoir and fluid loss. The slider on the steering ram looked wet, so I ebayed a new one over the winter. Clearly new or rebuild - no evidence it was ever installed.

Took the part to the dealer and asked them to diagnose the problem, and oh by the way I have a ram if that turns out to be the issue.

When I pick up the boat, they tell me that its fixed. I ask what was wrong and they say the ram was bad and they put mine on. OK.

Only problem is, on my 1st sea trial tonight there is no power steering, and there is still pressure buildup in the tank. I stop the boat to look, and the slider part of the ram is not sliding at all (or maybe 1/16 of an inch). The ram is also deflecting when I try to steer, which I don't remember from before. This is my 1st Volvo, but the old ram slider probably slid 1/2" or more as I steered. I assume it is a valve that when I move the wheel opens a hydraulic port to add pressure in the direction I want to go, with a feedback mechanism kind of like surge brakes in both directions - pressure is reduced as the ram reaches the place where the cable says it should be. Guessing here.

Anyway, I try some antics of throwing the wheel hard, revving in neutral while I steer, etc. Nothing works, although I do discover that at true idle there seems to be a little power assist but not much, but as soon as revs increase the wheel really resists turning. With engine off the slider still does not slide too much but it does a little. At idle it probably slides 1/4".

So here's my theory: The "Mechanic" reversed the lines, so I am fighting the pump instead of being helped by it? Would that create negative instead of positive feedback that would work to cancel out my actions instead of assisting them?

I'm wondering if I have the wrong ram. Are there any cable adjustments that would prevent the slider from moving on the cylinder, or is there a break-in period in which the slider loosens on the ram? All seem exceedingly unlikely. maybe the ram is just bad and I've been ebayed? The fact that I still am getting pressure in the tank makes me thing the ram was a red herring and I should just have them put the old one back on (in the unlikely case that it is still around).

Thoughts? Suggestions?
 

TwoWheels

Cadet
Joined
Jun 3, 2009
Messages
18
Re: New Volvo SX steering ram works at idle but not high speed.

Well, after looking again it is obvious that the lines can't be reversed. Oh well - I was hoping for something easy.

I'm down to the following possibilities, after reviewing an older engine manual (I couldn't find a downloadable engine manual for the 4.3GXi-F, which has a slightly different steering pump than the older models:

1) Still getting pressure buildup in the reservoir, which I understand means I have a leak in the return/low pressure side of the ram. Could the cap on the unused inlet to the pump be the source?
2) The ram seems a little more "wobbly" on the transom shield pivot than before (although I never really though to check it before) - how much play should there be? I'm wondering if the dealer installed without bushings? Do new rams come with bushings already installed?
3) I suppose the pump might be shot. It was run near dry in the past before I realized I had a large leak somewhere.
4) What else? Leak in cooler, but not sure that would explain air in system (seems like it would suck water and not air? That would explain why I seem to lose more fluid than I find in the boat.
 
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