Need Mack 5-Ton Power Steering Help!

[Memphisdoug]

Fluid of Choice?

Ok - one more question. What do you use for power steering fluid? The lubrication manual says either OE/HDO 10 or OEA. I don't know what either of those mean. What is a non-military substitute?

 

[highfavor1004]

Just plan hydraulic fluid

 

[Robo McDuff]

I am having this same steering problem on my Mack powered M51. On a right turn I get a little resistance and then the power steering kicks in. Left turn is difficult all the time now. The problem seems to have gotten worse since the weather got cold. I checked the fluid level in the reservoir and it is fine. Anyone with any ideas on what may be wrong and more importantly, how to fix it?

Reviving this thread; I am looking into the same problem. Left turn without problem, right turn in begin was difficult, now I need two persons to get the steering wheel around. This thread ends without clear answer on cause and solution (unless I missed something). Memphisdoug, did you manage to solve this problem and, if so, what what was the cause and how did you solve it?

 

[Memphisdoug]

Unfortunately, I have not had the time to work on this problem with my truck and it has been sitting for over a year without being driven. It got to the point the last time I drove it that I could hardly turn right at all. I had taken it somewhere and had to plan a route home using all left turns! I ordered rebuild kits for all portions of the steering column. I just have to bite the bullet and get it out of the truck and rebuilt now.

 

[Robo McDuff]

I was hoping to learn from your experience. I am getting busy with it now; the truck has to be drivable soon, in any case before winter starts.

 

[Memphisdoug]

Please keep this thread updated on what you do. I'd like to learn from your experience of what it took to fix the problem. Good luck in your repairs!

 

[highfavor1004]

My Problem was with that I had air in the Power steering lines. I had to lift the truck into the air and bleed the system out. I did so while the truck was running by turning the wheels left and top of the power steering tank and turned it right repeating process several times. when i put the truck back on the ground the problem was no longer there.

 

[Memphisdoug]

My Problem was with that I had air in the Power steering lines. I had to lift the truck into the air and bleed the system out. I did so while the truck was running by turning the wheels left and top of the power steering tank and turned it right repeating process several times. when i put the truck back on the ground the problem was no longer there.

What caused the air to be in the lines? Were you having problems with progressively harder steering prior to bleeding the system?

 

[Robo McDuff]

I did replace the oil and while trying had the wheels turning left and right, but the problem remained. That was in July 2012, truck has not been driving more than a few miles since then, still the same problem in summer 2013 and now.

 

[highfavor1004]

the way that is was explained to me that once the truck was sitting for a while with the combination of low oil that it can cause air to be pushed through the lines. The problem was the power-steering was only working when you turned right but not when you turned left. The issue progressively got worse to the point were it did not work at all.