Full Power Steering Is Getting Air In It. Why?

[Carl C]

I started a similar thread last year but I still have this problem. Even the guys at OSO seem to be stumped. I have Zeiger full dual ram, helm back power steering. It was fine for 2 seasons but at the end of last season I got play in the cylinders and had to bleed it. I was able to get all but about 1/8" of play out of it; It used to be rock solid. Now this spring, the same thing. I bled it repeatedly and was able to get it to about 1/8" of play. Boat ran great several times out. The steering still had about 1/8" play so I figured I'd re-bleed it and be good to go. Now after just sitting out of the water for a couple of weeks I am back to about 1/2" of play in the cylinders. The fluid level has not dropped and does not appear to be overheating or foaming. I have tightened all fittings and inspected all hoses and components. Any ideas?

[VetteLT193]

I can't find pictures of your setup anywhere because I can't figure out how to get back to other users albums...

Where is your extra reservoir mounted?

[VetteLT193]

I did some searching and I don't think you have an external reservoir?

Here is a theory:

you are pounding through the waves and the fluid is sloshing around in the PS tank. If you hit on just right while steering you could suck up a bit of air. I'm wondering if you notice it getting introduced into the system after rough rides?

If so... I'd add the external reservoir.

[Carl C]

There is just the reservoir on the pump. The sloshing theory makes sense but I don't think it is my problem. It was fine for 2 years of running on the big water.

[silverghost]

It sounds like an air leak in the system's or pump's intake suction side.
The system could be sucking -in small amounts of air at a time..

Check all intake suction side lines, hoses, & fittings and also the pump's shaft seal itself.

Pressure side leaks ~~~leak hydraulic steering fluid.
Suction side usually leaks suck-in air.

[justleft]

Have you changed the steering fluid ? The fluid itself may be aerated and while sitting some of the air comes out of suspension.
The fluid may contain some absorbed moisture and when the system is running the moisture is boiled to steam.

Contaminated (or cheap) fluid will expand and contract greater then pure fluid. Maybe sucking air in as the system cools.
Could be sucking air past the shaft seals on the steering rams but they seal under positive pressure. (seen that on heavy equipment)

I would fire it on the hose, after warm run it back and forth many times, shut it down (for safety).
Then wipe every fitting, hose, pump/helm/ram shaft with a white rag or paper towel.
It may not be pushing much fluid out but that doesn't mean it's not sucking air on cool down.

If fresh fluid helps then changing it periodically until the leak shows itself may be the best option.

[Fishermanjm]

i know this has nothing to do with why you are getting air in your system carl, butt,,, i am wondering, does that system still use the power steering pump and ram that would be found on a factory steering system,,, like i have on mine?

[Roadrunner]

I have the same steering system and the same problem, 1/8-1/4 inch play unless the engine is running then it is solid. After spending hours trying to bleed the air out I called Paul Everett about this a few years back. He acted as if it was no big as long as there was no play with engine running.

[Carl C]

I will try changing the fluid. I like that theory.

Fishermanjm, the only components that didn't come with the Zeiger kit are the pump and cooler. Those are the stock 525 parts.

Roadrunner, are you talking about play felt in the steering wheel or at the drive? My drive used to be rock solid with engine off. Now I can physically move it back and forth a good 1/2 inch. I'm pretty certain that play is still there with the engine running. The play in the steering wheel with engine off is normal.

[Roadrunner]

I'm talking at the drive. See it you can move it with the engine running.

[Carl C]

"I'm talking at the drive. See it you can move it with the engine running."

OK, will do but I'm still going to change the fluid. I've got a mixture of different kinds of ATF in there now and some of it is cheap stuff. The drive used to be rock solid no matter how hard I tried to manually move it back & forth with the engine off.

[joseph m. hahnl]

It's using the stock power steering pump to drive the fluid? If so the pump might be shot.

[Carl C]

Yes, the stock 525 pump. I will change the fluid first and then look into the pump. I have also thought about that possibility. It doesn't have a lot of hours on it though.

[joseph m. hahnl]

Does it howl like it's low on fluid?

[pipnit]

I've been taught / learned to never mix two different types of oils for any purposes.