Doral / Volvo D4 / DPH Leg - Haunted Steering???

[Nick_Pam]

Most estemed fellow Forumites,

Again I seek your support on a technical matter that is perplexing me somewhat...

We have a 2006 Doral Boca Grande fitted with Volvo D-4's and DPH legs....on starting the engines and leaving to idle, I have discovered that over a period of about couple of minutes or so, my outdrive legs "wander" from the centre position across to full right-hand lock and if I apply full left-hand-down, the same thing happens (but over a longer period of time of course).

Whilst out on the water, the boat will track straight providing that I continually apply some "left-hand down a bit", needing to correct by one full revolution of the wheel every couple of minutes or so.

I have checked the rams whilst the boat was out for a wash and brush up a month or so ago and there does not appear to be any leakage of steering fluid - the reservoir is topped up to the full mark, and the Volvo steering ram gaiter (mentioned in many posts here previously) is in place as fitted by the dealer.

Am I haunted????

Or is there some sort of adjustment in the system which is badly set, allowing one of the control valves to open slightly and cause the symptoms I have described?

Or is it worse???????? :-(

As I recognise that the steering oil is used in a recirculatory way, I can absolutely see (theoretically) how this could happen, but I've spent ages in the engine room and can't see anything obvious that might allow some sort of adjustment.

I've searched the D4 / DPH manuals, the internet and this estemed site but can't track any obvious clues or conclusions....you help would be most gratefully received.

Regards and fingers crossed

Nick

 

[spannerman]

Sounds like it could be the shuttle valve at the back of the engine on the transom, this directs the high pressure fluid to the rams and is controlled by the low pressure side from the steering wheel pump.
It sounds like its not centering and allowing fluid to creep to one side and push the drive over.

 

[Whitelighter]

Do you have an autopilot

 

[Nick_Pam]

Do you have an autopilot

Nope - no autopilot........

 

[Nick_Pam]

Sounds like it could be the shuttle valve at the back of the engine on the transom, this directs the high pressure fluid to the rams and is controlled by the low pressure side from the steering wheel pump.
It sounds like its not centering and allowing fluid to creep to one side and push the drive over.

Ermmm.........looks like I'll need a very small mechanic then, because I'm not sure I could even get close to it........

You certainly seem to be describing what I am seeing though........thanks.

Now......just need to work out how to fix it????

 

[aquatom]

Yes the valve on the transom causes this. Usually when the rams have leaked in the past and water has entered the hydraulic system. You need to change the valve and flush the system with clean fluid.

 

[Nick_Pam]

Yes the valve on the transom causes this. Usually when the rams have leaked in the past and water has entered the hydraulic system. You need to change the valve and flush the system with clean fluid.

Tom,

Cheers for this.....not sure we've ever had a leaky ram, but evenso....am I right in thinking that there is only one of these (on the starboard leg I guess as power-steering etc is driven from this engine) driving the other leg through the tie-bar and are the gods being kind by fitting all this stuff inside the engine-room, or is is external (necessitating a lift-out)?

Appreciate your help as boat is in Spain and I am currently in the UK, so can't look !!

Cheers

Nick

 

[spannerman]

Sounds about right, the valve block will be at the back of the engine with the servo pump. You may be able to get at it by removing the water hose which runs across the back of the engine to the turbo exhaust bend and maybe even the rubber 90 degree air hose which goes from the air filter to the turbo, its fiddly I know as I have had to change several rudder indicator morse cables which come through the transom behind the engine.