Engine: Power Steering pump

[Leroy Cook]

Well I have another problem! I installed a new GN Saginaw Power Steering pumpand after a few minites of running it got very hot.(200F-225F) I removed the pressure relief valve and added shims to reduce the pressure. I installed the valve and started the engine. T turned the wheel both right and left numerous time getting the air out. Again it ran hot!

Has anyone had this problem? What am I doing wrong? I ordered another pump and it is a few days out.

Help!!!

[JoeHall]

Where is it getting that hot? Sounds like you are using a heat sensor of some sort. At the pump body, it probably reaches temps similar to the motor it is bolted onto, given enough time.

How hot is the PS fluid getting?

Was it recently rebuilt? If so, it may be the re-builder goofed something up. If its just one that looked good, and you placed it in service, I'd run it an hour or two to see if it cools any.

About the only thing I have seen go wrong with the Saginaw pump is the vanes get sloppy & noisy, and shaft bearing lockup. Never seen one simply run hot. First time for anything though.

Good luck, and let us know how it turns out please.

[karterfred88]

Check how close your hoses are to the left exhaust pipe. The further away you can get them the cooler the fluid stays and longer it lasts. On my Avanti engine temp at 180 power steering fluid returning to the pump is almost 250 due to the radiant heat from the exhaust. It cools down when driving it, but stationary, and idling the fluid sits still since it doesn't move till the valve moves so it just sitting there getting hot!

[Leroy Cook]

I may have a cyl. problem. Thr return line is hot also. I know there has to be some 'by-pass' and as soon as I get the new pump installed I'll post the out come. Maybe I have to add a cooler in the return line.

[Leroy Cook]

Well I installed another Saginaw power steering pump. I ran a hose from the outlet back into the tank. It ran for twenty minites and did not get hot. I conected it to the steering box and it ran hot! (Over 200F) There was no problem until I installed the Saginaw pump. Maybe the pressure is to great?
This pump has two internal valves. One is a pressure relief valve. The other is a spool. This spool is a "pressure comensated flow control". When the wheel is not moved the total flow is returned to the inlet of the pump. When the wheel is moved thisvalve shifts and the required flow is ported to the steering box.

I am going to atempt to reduce the pressure relief setting. Is there any specs on what the original pumps pressure was?
I did this when I installed the Chevy 350. I had no idea I was going to get in trouble! I have seen where guys up this pressure by removing shims in the relief valve. Hopefully by adding shims I can lower it!

Any ideas on this? Has been done before?

[karterfred88]

Well the pump isn't heating the fluid-is it. You circulated the fluid through it bypassing the gear and it didn't get hot. So run it that way again, and take the temperature of the gear with no fluid going through it. How hot does it get! Fluid flowing through a hot steering gear is going to get hot. I doubt changing pressure will do anything. Find the true source of the heat. Exhaust pipe, manifold but it's probably not in the system itself. To build heat in a hydraulic circuit, you have to work the fluid hard, like turning lock to lock while stationary for an half hour or so with no rest or motion of the vehicle getting cool air under it. If you can't find the source, drive it, let it get hot, forget about it till the fluid starts discoloring. If it does, put a cooler on the pressure side, mounted in front of the radiator. Many manufacturers have P/S coolers.

[Leroy Cook]

I am still checking the heat problem. WhatI need to do is to install a pressure gauge in the discharge line. I feelthe steering box is permitting flow to be ported in and out when the wheels arenot being turned right or left.

The pump is a vane pump and a positive displacement this means the outputvolume remains the same except when the engine speed is changed. The pressurecompensated spool regulates the flow and the relief valve sets the maximumdischarge pressure.

Iam looking at fittings to install a pressure gauge in a Tee. This way I can seethe pressure when the wheels are turned and when not turning.

This pump is getting hot because it is pumping under pressure. Volume XPressure divided by 1714 equals horsepower.

(Example) 3.5 GPM X1000 PSI = 3500
3500 divided by 1714 = 2.04 HP

Now when the wheel is not being turned the pressure is reduced by the spool andthe flow is routed to the reservoir

[Leroy Cook]

Again the font is out of control! I may have to go to font school!

[JoeHall]

Are you sure there is a problem with the heat?

Click on font size, in the text box, and select the font you prefer.

[Leroy Cook]

Again the font is out of control! I may have to go to font school

I am still checking the heat problem. WhatI need to do is to install a pressure gauge in the discharge line. I feelthe steering box is permitting flow to be ported in and out when the wheels arenot being turned right or left.

The pump is a vane pump and a positive displacement this means the outputvolume remains the same except when the engine speed is changed. The pressurecompensated spool regulates the flow and the relief valve sets the maximumdischarge pressure.

Iam looking at fittings to install a pressure gauge in a Tee. This way I can seethe pressure when the wheels are turned and when not turning.

This pump is getting hot because it is pumping under pressure. Volume XPressure divided by 1714 equals horsepower.

(Example) 3.5 GPM X1000 PSI = 3500
3500 divided by 1714 = 2.04 HP

Now when the wheel is not being turned the pressure is reduced by the spool andthe flow is routed to the reservoir

[karterfred88]

Leroy,
What steering gear is this going through? Delphi recirculating ball style gears show an operating temperature of 275 degrees as normal. I think you're over thinking this. How does the steering respond? If it is way too light then you have too much pressure. If it feels normal then you should be OK. If you're running it through a Bendix style control valve and ram at those pressures the power steering fluid would be pouring out the control valve. Help us here. Fill us in on the exact combination of power steering pump and steering gear/ type of power steering you are working with.

[Leroy Cook]

After three power steering pumps I found my problem. I put together a 'test stand'. This was a 110 volt electric motor driving the power steering pump. I used two different sized V pulleys to get the pump to spin at 1200 RPM. I install a pressure gauge, a shut off valve and a Headland Flow meter. With the shut off valve I could check the maximum pressure. (975-1025 PSI)

The pump checked out fine and just running for a couple of hours the fluid only reached 118F. Now when I installed it on the car it ran hot! I removed it and put it on the 'Test Stand'. This time I kept the discharge hose attached to the pump. Now I quickly found out the problem is the hose! I cleaned out the hose and tried to put a length of stainless steel lock wire in the hose. It has some sort of blockage. I put an air nozzle and tried to blow though the hose and found it almost completely blocked.

I am having a new hose made! I sure am glad I stuck with this. I almost was going to remove the power steering system!

Thanks for all of the replies and messages in this matter!

[rkapteyn]

New hoses are available at:

http://www.studebakerstore.com/Studebakerstore.com/Welcome.html

Robert Kapteyn