Community Forums

ltcdljones · 05-24-2022, 11:21 AM

I have a 2019 Newmar Ventana on Freightliner chassis with 400HP Cummins (25000 miles) where power steering reservoir overflows occasionally after long drives in higher ambient temperatures (maybe 85 degrees or higher). When this happens, flow in the reservoir appears very turbulent with fluid coming out of the reservoir at the cap. The o-rings on the cap are not cut. The fluid is clear red with no evidence of contamination and no unusual noise from the pump or steering box. I first notice this a little while after mistakenly putting about a pint of water in the PSF reservoir thinking it was the engine coolant reservoir after a low coolant alarm. I run it for a couple hours on a trip home before realizing what I had done. The next day, I pumped the system down twice with the return line to a bucket keeping the reservoir replenished as the milky fluid returned to the bucket. Since that time, maybe 2 years ago and 6000 miles, the reservoir has overflowed maybe 4 times all at the end of long trips in hotter weather when I stopped and left the engine running while unhooking tow vehicle. I do not believe there is any remaining water in the fluid (Dextron 3). I have not changed the filter in the reservoir. If this caused excessive wear to the PS pump, is there any way to prove this before replacement? I have not checked the temperature of the fluid. I’m thinking the PS fluid is free of water since it’s clear and has been replaced twice or maybe 3 times with overflows. Thoughts?

bentjm · 05-24-2022, 02:59 PM

Quote:

Originally Posted by ltcdljones

I have a 2019 Newmar Ventana on Freightliner chassis with 400HP Cummins (25000 miles) where power steering reservoir overflows occasionally after long drives in higher ambient temperatures (maybe 85 degrees or higher). When this happens, flow in the reservoir appears very turbulent with fluid coming out of the reservoir at the cap. The o-rings on the cap are not cut. The fluid is clear red with no evidence of contamination and no unusual noise from the pump or steering box. I first notice this a little while after mistakenly putting about a pint of water in the PSF reservoir thinking it was the engine coolant reservoir after a low coolant alarm. I run it for a couple hours on a trip home before realizing what I had done. The next day, I pumped the system down twice with the return line to a bucket keeping the reservoir replenished as the milky fluid returned to the bucket. Since that time, maybe 2 years ago and 6000 miles, the reservoir has overflowed maybe 4 times all at the end of long trips in hotter weather when I stopped and left the engine running while unhooking tow vehicle. I do not believe there is any remaining water in the fluid (Dextron 3). I have not changed the filter in the reservoir. If this caused excessive wear to the PS pump, is there any way to prove this before replacement? I have not checked the temperature of the fluid. I’m thinking the PS fluid is free of water since it’s clear and has been replaced twice or maybe 3 times with overflows. Thoughts?

How exactly did you "pump the system down".

ltcdljones · 05-24-2022, 03:22 PM

Disconnected return line connected to the reservoir and put over bucket, filled reservoir and had buddy start the motor for a few seconds, then stop. Filled reservoir and repeated process. Once I had clear returns, I turned the steering wheel to right, then left limit to get air out of the system. Repeated this until it appeared air was out of the system while keeping the reservoir full.

Unplanned Tourist · 05-24-2022, 03:35 PM

Sounds like a very small amount of water is still in the system. When it boils, steam pushes fluid out.

Do another flush with new oil.

Dutch Star Don · 05-24-2022, 03:43 PM

I would change the filter and do one more flush. The filter is very easy to replace.

bentjm · 05-24-2022, 05:18 PM

My 2005 MADP has a remote hydraulic filter as well as the one inside the surge tank. If you have a remote filter, swap it out as well.

ltcdljones · 05-24-2022, 08:26 PM

Thanks for suggestions. I will flush again with new filter.

Dutch Star Don · 05-25-2022, 04:30 PM

Flush without the filter if you can and then install the new one when you're done.

ltcdljones · 05-26-2022, 06:59 AM

Will do. Thanks

RichardE · 05-27-2022, 01:44 PM

Keep this in mind when developing a flush strategy.

Any time the system sits, any water will precipitate out of the ATF and collect in low places. It will remain there until enough circulation and temperature causes it to go into emulsion in the ATF.

So, if your flushes are done with the system cold, and after the coach has been sitting. It will take a LONG time to get the water out of the system.

You can prove this to yourself if you are skeptical. Pour some ATF in a clear jar, add an ounce of water. Shake it up. The water will disappear and the ATF will look cloudy. Let it sit for a couple of hours, the water will collect at the bottom.

You might think about temporarily adding a hydraulic oil/water separator to the system. Don’t use a fuel separator since they are not rated for the pressure.

Do you have a way of draining the low points in the system? If so do so after the coach sits for day or two.

But before you get too far, you might want to check the theory that water is indeed the problem. Next time you have the overflow condition, collect a quart of the hot ATF. Let it sit for 24 hours. If there is water in there, it will collect at the bottom of the jar. This is the redneck way.

Or you could send it to one of the oil analysis places like Blackstone, and they can tell you if it is contaminated with water. This is the scientific way.

Whatever you do, DO NOT put something like HEET, or other fuel drying agent into the system.

ltcdljones · 05-28-2022, 08:31 AM

Richard, Thanks for suggestions. Unless I’m missing something on my problem. This is either a small amount of water still trapped in the system or I created premature wear in the ps pump which generates enough extra heat when run or operated on longer trips in hotter weather to cause the overflow condition. I have asked freightliner for a schematic of the system but have yet to get anything from them. They indicated during a telcon yesterday that I only have the one filter in the reservoir and no vents valves in the system. Once I flush the system again, I’m going to start checking and recording ps fluid temp, ambient temp and drive time in an attempt to determine if it may be the pump itself starting to fail. Any further thoughts are certainly welcome and appreciated.

bentjm · 05-29-2022, 03:19 AM

The steering box itself holds some hydraulic fluid. I have no idea how to completely drain it - maybe turning the tires lock to lock as you are flushing it would help.