R27 steering issue

[Toki]

I searched the forum and found what may be the answer to a steering problem on my 2016 R27, but just wanted to run this by the Tugnuts brain trust before making yet another trip out to the boat. Here's the issue:

A charter customer claimed to lose all manual steering. Upon return, hydraulic reservoir at helm took MUCH fluid (more than half a quart I'm told). No signs of leaking fluid anywhere. After extensive bleeding, we're pretty sure any air is purged.

A sea trial had the boat needing constant correction to port to hold a straight line. Upon further inspection at the dock, we found the following:

- Very little resistance turning the wheel beyond the stops to both sides

- Able to move the tiller by hand (with maybe ~20 lb force), moving ram back and forth, without wheel turning

- All seems fine when under autopilot

In searching the forum, I found this from a factory rep:

If you are experiencing issues where the boat will require constant steering to starboard to keep a straight heading even though you have no problems turning to port, you may have issues with the GHP 10 pump. This is easily diagnosed. The pump has three brass screws that will need to be turned in to their closed position for the test. They are easy to find on the head of the pump where the hydraulic lines enter (should be facing aft). Just turn them in until they bottom out and stop moving. Do not turn them hard. Once this is done, it will effectively remove the pump from the steering system. Then if all goes back to normal on the steering, the pump is the issue.

Sounds logical, although I sure hope I don't need to spring for a new pump!

So, a couple questions:

Are you all in basic agreement with this diagnosis process for this particular issue?

If the problem is the valve block on the AP pump, is it possible to buy and swap out just that valve block rather than the whole pump?

Thanks all!

 

[BB marine]

From your description of your issue it may be a pump issue. If you have all lines bleed of air and you still have a " mushy" helm which is not locking in the normal 4 turns lock to lock I would suspect the pump. First is to test the steering with the 3 brass shutoff screws closed located in the shutoff valve manifold. The shut off valve manifold is used for 2 purposes. (1) to troubleshoot the pump with issues you are describing and (2) to make it possible to remove the pump for repair without the need to re-bleed the system. Think of the shutoff manifold as block valves to isolate the GHP 10 pump from the helm and cylinder. If you find that after testing the helm with the shutoff screws closed all helm steering is functioning properly then the pump proves failed. Leave the shutoff valve in place (screws tightened) and remove the pump from the shutoff valve block for repair.

The one item in your description that I question is where did the oil go? Was the helm known to be full of oil? The hydraulic oil is in a closed loop. If it is full it should stay full. It can't use oil. If the level drops (1) the system has air in it and some air has vented out of the cap and the air was replaced with oil dropping the level or (2) the system has a leak some where.

If the problem is the valve block on the AP pump, is it possible to buy and swap out just that valve block rather than the whole pump?

The problem would not be the valve block it would be the pump.

 

[Toki]

Thanks Brian. Yes, where did the fluid go, that's a mystery. This boat is new to me, as part of the survey we didn't bleed the system so it's possible fluid was low previously, although steering was fine then. I checked ALL the places along the circuit, no signs of leakage.

Regarding that shutoff valve manifold, is that simply a pass-through for the fluid, or are there check valves or some such thing embedded in there? Not knowing how this thing works, I assumed check valve(s) go bad allowing fluid to bypass the pump. But it sounds like that's not the case, and the fluid bypass is happening within the pump itself?

Also, all GHP 10 pumps I see for sale include the shutoff valve manifold mounted on them. Are you saying I'd remove that new manifold and attach the old one to the new pump?

 

[BB marine]

Also, all GHP 10 pumps I see for sale include the shutoff valve manifold mounted on them. Are you saying I'd remove that new manifold and attach the old one to the new pump?

I would call a Garmin repair center or Garmin technical. It may be an issue with the valves in the pump leaking by and a repair center could repair the issue. This may be less expensive than replacing the complete assembly and there will be a verification of the issue found and repaired. When the pump is removed the steering from helm is still usable if the shutoff valves are seated closed. If I purchased a pump and I knew my Hydraulic system was properly bleed I would install the pump to the existing shutoff manifold. I believe it is a o-ring seal between the manifold and pump assembly.

Operating the Shutoff Valve
The 2.0 L and the 1.2 L pumps feature a shutoff valve for troubleshooting and repairing the system. To engage the shutoff valve and isolate the pump from the hydraulic system, fully tighten the three brass screws near the lower hydraulic connectors. To disengage the shutoff valve, loosen the three brass screws until they stop.

To remove the pump from the shutoff-valve manifold:
1. Tighten the three brass screws near the lower hydraulic connectors.
2. Remove the four socket-head cap screws that connect the manifold to the pump.
3. The manifold is no longer connected to the pump, and the pump can be disconnected from the ECU and removed from its mounting location. The hydraulic steering system will operate normally.

To reconnect the pump to the shutoff-valve manifold:
1. Remount the pump and reconnect the pump to the ECU.
2. Connect the manifold to the pump using the four socket-head cap screws.
3. Loosen the three brass screws near the lower hydraulic connectors until they stop. Do not loosen the screws past the stopping point.

I hope this helps. The Garmin help line in my opinion is great. You call Garmin, give them your phone # for a call back (its automated). Normally I have received a call back with in 2 hours.

 

[Toki]

Thanks Brian.

Today I.tried shutting off those 3 manifold screws, and like magic manual steering is completely fixed, all the bad symptoms resolved. So it looks like it's the pump. But before I sink a boat buck into a new pump, I'll take your advice and chat with with Garmin tech support and see what my options are.

Thanks again.

 

[Toki]

Garmin tech support confirmed that it's definitely the pump at fault. Rather than $1100 for a new pump, they offer a repair/exchange for $400, so the bad pump is out of the boat and on it's way. Should have the replacement next week.

Thanks again for the advice.

 

[BB marine]

Good to hear Garmin came through with a less expensive solution. The best part of the solution is they will be able to confirm what component failed and when you reinstall the pump you will have confidence that you didn't just parts change. You troubleshot and repaired per procedure. Removal of the pump from the manifold makes the repair much simpler too.

 

[stwendl]

On a related note. On my r27 the pump is installed forward of the transducer. Due to small leaks on the manifold, steering fluid was making it into the cavity where the transducer is installed. The oil attacked the binding of the 5200/4200 and thus caused leakage of the liquid in the cup

 

[Toki]

Good to know stwendl! There's oily water in that transducer cavity in my boat too. I'll make a point to clean that up and keep an eye on that area.