The Stovebolt Site Forums The Shop Area Engine Shop Unconventional power steering question

I have posed this question on the tractor forums without much reaction, so I though I would come to the one place where more readers have good answers.
I have a Phord tractor (1956 850) with factory power steering. The factory PS pump had died and been replaced with a small Escort pump (I think) before I bought it. Even though the pump works, the steering response is slow. The owners manual stipulates that the PS system uses the same universal fluid as the transmission. Since that is so much thicker than Type II Dexron ATF, the system must warm up before it works at all, but even when it's hot, the response is slow. I have been tempted to just change the fluid to ATF, but don't want to risk damage to the steering box, which has been rebuilt, and don't know how the steering pistons will perform with the lighter oil. A rebuilt PS pump is almost $700, so you can understand why I am looking for alternatives. Would a pump from a full-size truck or car improve the performance, and how do I reconcile the different oils?

It sounds to me like your problem is volume. You need a bigger pump. As in more GPM. If it where low on power it could pressuer. If it will overcome the the resistance that it should but is slow to do it that is volume.

Russell,

Chevron used to sell a product called Tractor Hydraulic Fluid. It was used in rigs that had a common sump for final drive, hydraulics and transmission. The viscosity of this product is about a 10 weight. ATF is slightly thinner...sort of a 9+ weight. If you are using a product like the Tractor Hydraulic fluid, you can see that the viscosity is almost the same as ATF.

This would mean it isn't the viscosity of the fluid in your PS pump that is causing the slow response, but lack of volume (GPM). You said it was a small pump from a Ford Escort. I think you have pegged the problem.

Stuart

There are a wide range of steering systems in the automotive/truck world and probably in the tractor business also. In many cases components are not totally compatable with another make/brand/system. For instance if you install a mustang II front end on an older truck and use a late GM PS pump you have to reduce the pressure from about 1400 PSI to about 900 PSI for it to operate correctly. However, the older GM systems used substantially lower pressure.
Try to find out what pressure the system needs to operate on and install a pump that meets these requirements. You can change the pump pressure on a GM pump by adding/subtracting washers in the control valve. Other makes may have a similar set up. Fred

I am with Fred ,the problem is the pressure control valve. The pressure is too low and on most pumps this valve can be adjusted.. some times as simple as turning a screw and in some cases they require shimming by, as mentioned, removal or addition of Washers.I don't know what pump you have but there should be a shop in your area that rebuilds PS pumps and they should be able to help you.

On some of the GM boxes (the Grand Ams come to mind) there's an orifice that can be drilled out to incease flow. Don't know how the Escort pump is regulated,
Scott

Also, there's quite a few aftermarket tractor parts places out there. Have you ever priced the correct pump?

Have you tried Dennis Carpenter? They do carry Ford tractor parts, although I dont remember which models. Tractor Supply would be a good place to check also.

A lot of factory systems run ATF for power steering fluid. My BMW calls for Dextron III. My RX8 calls for electrons- the power steering is electric.

What fluid are you using in it? Hydraulic fluid or transmission grease? 80/90 gear lube is much too thick for it. I believe I would use regular power steering fluid or Dexron III.

Thanks, guys. You have given me the leads I need. The system uses universal tractor fluid, not 80/90 gear oil. Lack of volume certainly seems to be the most logical cause of the problem, and I had no idea that PS pumps could be adjusted--I never needed to know. I have a GM pump that I'll take to rebuilder to examine and tweak for proper flow. Thanks again.

The volume of the pump can't be ajusted only the pressure. And it sounds to me like your problem is the volume. The lighter oil may make some diffeance if the pump is cavitating on the heavy stuff.