Simrad autopilot oil leak

[Hammer]

Autopilot oil leak.

I've observed a small amount of oil leaking from my Simrad (2019) reversible pump motor over the last few weeks. The oil seems to appear right under the fittings.

Yesterday I got a "no rudder response error" when trying to engage the autopilot. The pump motor runs and the controller shows the correct course. But with the boat moving the autopilot just cuts out with the "no rudder response" error.

Sitting at the dock, when I engage the autopilot you can hear the motor running but the rudder is not moving.

Simrad manual says motor has fittings with O-rings. Should I just try to tighten the fittings? Should I replace the o-rings?

Where would I get the o-rings?

The boat has a seastar dual helm hydraulic steering system and I can still steer the boat. I have not checked the oil levels at the helms yet.

Any guidance appreciated.

TIA

 

[twistedtree]

I'd start with the oil level. I expect you will find it low as a result of the leak, and probably too low for the pump to work.

 

[O C Diver]

I would replace the oring, while you at it, do the other 2 also. Most hydraulic shops carry a good selection of orings. Take your fitting and the oring with you. Obviously you will need to bleed your steering system again. Make sure you have extra oil and the instruction manual if you've never done it before.

Ted

 

[mvweebles]

Physically, where is the pump located? Is either the highest "pump" (meaning including helm pumps - where the steering wheel is attached)? A little more info on type of boat and configuration might help.

First and most likely is fluid loss as TwistedTree mentions. But that assumes the pump is up high, otherwise you'd feel the steering loss at the wheel first (flybridge if you have one).

Peter

 

[Hammer]

Physically, where is the pump located? Is either the highest "pump" (meaning including helm pumps - where the steering wheel is attached)? A little more info on type of boat and configuration might help.

First and most likely is fluid loss as TwistedTree mentions. But that assumes the pump is up high, otherwise you'd feel the steering loss at the wheel first (flybridge if you have one).

Peter

Thank you for the response.

The vessel is a Mainship 390 trawler 2002 with upper and lower helms. The steering system is Sea Star hydraulic for inboards with one steering system cylinder fastened directly to the steering tie-bar-rod for the dual rudders.

There is a vented fill plug on the upper helm. A second, unvented fill plug is found at the lower helm.

The simrad auto pilot pump is located right next to the sea star cylinder near the the steering tie bar to the dual rudders. The auto pilot pump is lower in the boat than both helms.

 

[Hammer]

I'd start with the oil level. I expect you will find it low as a result of the leak, and probably too low for the pump to work.

Which helm do I top off first? Logic would suggest the upper helm. Is that correct?

 

[Shrew]

Which helm do I top off first? Logic would suggest the upper helm. Is that correct?

It's all one hydraulic system, however the steering pumps won't necessarily bleed the AP pump directly.

1) Fix the leak first.

2) Fill the Fluid from the upper bleeder valve.

3) Bleed the air from the hydraulic fluid. I use a bleeder hose and quart bottle, preferably only half full. I punch a hole in the bottom of the bottle (Upside down) to release the air. Then sit there turning the wheel from lock to lock until all the air is out.

4) Repeat this process using the AP turning the rudder from lock to lock using the AP pump until all the air is out.

 

[BCRyan]

Do you not have a reservoir somewhere in the system?

I have the same AP pump and there's a ~1 gallon cylinder in the ER with an oil filter next to it. The AP pump and helm draw fluid (as needed) from this reservoir. The level in this needs to be within range and the system charged to 20 PSI in order to function correctly.

 

[Hammer]

Fixing the leak is going to be a little more challenging. Check out the attached pictures. The oil is under the pump. But the three fittings appear dry. I wiped the fittings with a clean rag and there was no oil residue.

 

[Hammer]

Phots of oil leak Simrad RPU80

Here are photos of the simrad rpu80 drive unit on the vessel. The oil is puddling below the unit. But when I wiped the fittings with a clean rag, there was no oil residue observed on the rag. Does this mean the drive unit is leaking?

 

[mvweebles]

Assuming both helms work properly when steering manually, my hunch is issue is not low fluid (though they is very common). From thr pictured, fittings do appear dry. I've had an AP pump motor fail, but not the head so I'm not sure if this is common or if it makes sense to repair it. I hate to punt, but I'd try calling Simrad tech support, but I wouldn't be surprised if they give a canned answer about bleeding and refilling (you could try this, but I really doubt that's the issue).

Hoping someone else chimes in. 3-years is a pretty early death for a pump. So maybe something else?

Octopus pumps are a lot less expensive and solid quality. https://www.hodgesmarine.com/octoctaf1212-octopus-autopilot-pump-type-2-adjustable-rever.html

 

[CharlieO.]

Here's the manual. It shows a few orings and an oil seal. Page 33-34.
Not sure if it the exactly the same pump.


https://www.defender.com/pdf/RPU80_manual.pdf

 

[Hammer]

oil seal

I just found and downloaded the service manual for the drive unit. There is an internal oil seal between pump and motor that can be replaced as part of routine service. I just ordered the seal kit from Simrad. Hopefully that will cure the leak.

There are no shutoff valves on my system so I will probably end up draining the system and putting in oil new oil and then bleeding. Sea Star recommends putting all new oil anyway.

 

[Hammer]

Repair complete.

Just to close out the thread with the update and solution to share. I removed the pump and took out the two screws attaching the pump to motor. Once apart, I could see where the oil seal had been leaking. There is also a very small weep hole, which allowed the fluid to drain slowly.

I replaced the oil seal. Cleaned the pump housing. I also took the motor housing off and cleaned the brushes and vacuumed the dust. I reassembled and installed the motor/pump back on the boat.

I drained the steering system and added four new quarts of sea star hydraulic fluid. I bled the system while adding new fluid, first at the upper helm, then the lower helm. Took about another quart of fluid for a total of five.

Tested the autopilot, and the drive unit is once again operating correctly. The autopilot steers the boat. Manual steering is firm and responsive, better than before the repair.

Thanks to all who helped with information.

 

[Sleeping Bear]

Careful with this.

Last time I changed my pump, I bled the system as insrtuctions, all good, everything working.

First trip an hour out, I was down below tending to something, when the admiral slowed right down, (our signal there is a problem), and we had no steering at the upper helm when she turned off the AP.

Seems I didn't get all the air out, and it eventually worked its way to the upper helm.

We were coming into a marina when this happened. Steered with the AP to a dock to refill steering, could have been scary in a less calm situation tho.