I recently bought a new to me 2005 ‘27 Ultra Shadow and I am working through some bugs. The boat has a 525 with IMCO dual hydraulic steering to the helm.

I dropped it in the water a few days ago and the hydraulic steering was stiff and difficult to operate.
I topped off the reservoir, bled the system by cycling the steering wheel lock to lock for at least 10 minutes.
This seemed to do the trick. The boat ran great and steering felt normal.

Fast forward a few days, I just noticed that the power steering fluid is now backflowing and overflowing through the reservoir cap. Essentially, the system is draining itself through the reservoir cap.

There are no signs of leakage at the rams, hoses, fittings, or PS cooler.

Any idea what would cause the system to “backflush” or push excessive fluid back into the reservoir causing it to overflow ?

Side note- I’ve done my due diligence and searched through the forums, but found no helpful info for my specific problem.

I think you still have air in the system, be more specific on how you bleed the system.....what drive is on the boat

The boat has an XR drive.
I filled reservoir and slowly worked the steering wheel from lock to lock, holding it at each lock for a second or two.
I made sure to keep the reservoir from running low, and cycled the steering wheel until no more air bubbles were present.

I ended up using one and a half bottles of fluid. And I now have about that much that has overflowed.

Are you running a ps cooler ?.. if you dont pinch off the return line the fluid will follow the least path of resistance and usually just goes in a circle instead of flowing through the rams external at the drive

After I installed ext steering on mine, I had to loosen the hose connections at the transom to bleed the last bits of air trapped in sys.

ill have to try to bleed the rams at the outside rear of the boat.
I just don’t understand why the system would burp out about 40+oz of fluid a few days after running it.

Is your reservoir lower than the pump?

I thought these systems were self bleeding? I have never had an issue. I disconnected my hoses this past summer to do some maintenance, retightened hoses, full left, full right a couple times. All good. My reservoir is at least 12" above pump and rams.

The reservoir is higher than the all other equipment, except the helm.

When air is trapped in the high press portion of system, it's displacement can be very small and go unnoticed. When the trapped air eventually passes to the low press (return) side, it expands rapidly pushing fluid into reservoir much faster than it's being drawn out (i.e overflow).