hard hydraulic steering

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vista268

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Joined
Dec 13, 2007
RO Number
29113
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5
I am having a problem with my power steering and hope someone has a solution. I have full hydraulic to the helm with external Imco rams (twin bravo drives). At docking speed, the system becomes very hard to turn. A common suggested solution I have heard is to drill out the orifice in the power steering pump to improve flow. We did that, but no improvement. Any thoughts on a possible fix?
 
Why is your Power steering pump not assisting or Powering like it should?
I'd start there.
 
It does assist, but as you turn the wheel a couple of times, kicking in and out of gear as you dock, the steering gets progressively harder. I think it is loosing pressure at low idle, making the steering hard. Fluid level is good, pump filter has been changed. Someone suggested a smaller pulley to bump pressure at low speed, but I would think this could lead to too much pressure at higher speeds.
 
Has this problem always been there, or has it developed recently?

I'm having trouble picturing your setup. On our simple single MerC Alpha One Gen Two setup, a mechanical rack and pinion drives a push/pull cable. This cable attaches to the MerC "transom assembly" which includes the Power Steering Ram. The Ram is powered by an ordinary GM power steering pump on the 5.7 SBC engine.

Am I correct in thinking that you have a Hydraulic Helm, with Hoses to the Transom Assemblies? Sounds complicated, but let me mention two issues that can make the steering miserable on our little Sea Ray:

1. Our steering cable has to be slick free effortless. If a cable is failing (getting sticky) the helm will spin easily with the cable disconnected from the transom assembly BUT STEERING GETS STICKY. With the old cable removed and laid out next to a new cable, it becomes apparent how difficult to push it's actually become.

2. The cable attachment to the transom assembly is not simply a threaded protrusion. It is actually the Shuttle Valve that directs hydraulic fluid to apply power to the power steering! Hard to see, but there are Wrench Flats on the inboard end of that threaded attachment. The flats MUST BE VERTICAL once I finish tightening the steering cable nut.

Does any of this apply? Have you checked and it's all OK? Then I'd ask: Are your power steering Hoses (pump to transom, probably through a cooler) collapsing internally? Blockage in the Cooler? Fault in the Pump?

I wonder if something is heating up as you maneuver that doesn't get the same workout at cruise speed.
 
Has it always been hard at docking speed? Are you sure you have a hydraulic helm not an add on that uses a mechanical helm station and external rams? An add system is harder to operate at idle and more so when attempting to turn the wheel rapidly.

Lastly, contact Imco they are a good outfit.
 
Thanks for the input. Yes, the problem has always been there. And yes, I have full hydraulic to the helm, no cables at all. It is an offshore style set up (38 Powerquest Avenger). We did talk with Imco and they were the ones who recommended drilling out the orifice. One other suggestion was to install a cross over which connects both power steering pumps. On my current set up, the starboard pump runs the system and the port just circulates into itself-this is typical for this system. Merc makes a system to connect them so both pumps feed the system, leaving you with power steering, regardless of which engine is running. Has anyone tried this approach? I hear some fishing boats do this so they can troll on either engine and shut the other off, thus balancing the hours.
 
Are the engine idle RPM's at spec?
Belt glazed and slipping.
 
Is the steering easy when the engine is off?

Can you disconnect the steering ram from the steering linkage of the drives? Then go thru the same procedure that causes hard steering. This will eliminate the drive and linkage. Also test steering with engine off. If it's easy I would tentatively eliminate the hydraulic steering and power steering pump and look at the steering ram...like leaking seal in the ram or shuttle valve not lined up right...like jd said.
 
Yes, the RPMs are in spec. Again, I appreciate all the thoughts. Drives turn easy when rams are disconnected and system works fine at above idle speed. We are going to check the flow of the pump this weekend and see what it is. We finally were able to get a spec today, so we know what to compare it to. I will report back.
 
My friend has a 24' searay like mine but he doesn't have power steering. You really gotta be in shape to steer that boat at any speed. Your power steering has to be working some or you couldn't steer at all.
 
yes, works excellent until you are into a final docking maneuver, bumping in and out of gear. That is when it looses pressure and becomes very difficult to steer!
 
Could it be something really off the wall?
The Hydraulic pressure is "stacking" during the "final docking maneuver, bumping in and out of gear"?
Maybe there is a problem with the pressure release adjustment.
Something that allows pressure to (one way) come off so the Hyd shift to the (other way) can take place.
 
Hmmmmm! That's a possibility. Good guess TM.

I would really check into the alignment of the power steering ram...but that slipping belt is a sneaky possibility.
 
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