I just installed PS in a 1949 Packard. The modified system uses a 1953 Chrysler 6V Generator that has a PS Pump attached to the back of it and the other end of the hoses is a Monroe external hydraulic actuator that is installed in lieu of the center link and this is the unit that the 1955 Packard used for PS. The Chrysler manual specified SAE-10W however the Packard manual specifies "Ultramatic" fluid (also called Type A fluid however some say Type F can be used as a replacement). I used regular old PS Fluid from Autozone and the system makes a humming sound when the power assist is in action. Does anyone know what kind of fluid I should use???
ATF. In a P/S unit, anything clean will work so long as it is compatible with whatever is in there now.
>ATF. In a P/S unit, anything clean will work so long as it is compatible with whatever is in there now. There was nothing in it before yesterday. I used regular old PS Fluid from Autozone. The system hums a bit when the system is under load so a suggestion I got on HAMB was to run thicker fluid. Can I drain the PS Fluid and replace with Type F? Naturally not all of the fluid will drain out so the PS Fluid and Type F will be mixed so are the two compatible? THANKS!!!
If you are talking about humming when you are doing a maneuver like parking then the humming is about normal, when going down the road you shouldn't be able to hear any humming..Type A, F, or 10w don't think there is much viscosity difference..Some one will chime in ..
A bit of humming may be normal. There may be a mis-match in the volume or pressure requirements with the matching of the parts you used to make the setup work. You may have a restriction in a line due to adapters ect. Is the system working correctly? Is the "feel" right going down the road?
I'd go with whatever the pump originally called for over what the manufacturer of the cylinder specifies. Any hydraulic pump using SAE 10 oil would be a non-detergent oil. For years, a lot of heavy equipment manufacturers like Caterpillar and Grove Crane called for ISO 32 hydraulic oil, or non detergent SAE 10 as a suitable replacement, so the use of motor oil in a hydraulic system isn't unusual at all.
I would NOT use automatic transmission fluid in any power steering unit on anything except in a dire emergency. I've repaired too many of them that had trans fluid in them and were noisy because of it. With that pump I'd follow what metimunchr suggested in post 6.
I might try draining the system and going with SAE 30W to see if I can get a bit more low RPM pressure. The Chrysler and the Monroe (Packard used this actuator) use both 650 max pressure systems. Ill let you know!!!
It seems Packard used two different PS systems in 1955 and 56. They used a Bendix system (that is the one I have the manual for) and they also used a Monroe system and that is the one I actually installed in the car. It seems the Monroe unit needs 900 PSI to operate correctly.
Only the dealers had power steering fluid for many years. I sent samples of power steering fluid and automatic transmission fluid to the company that tests our hydraulic and engine oils and the only difference was the dye color. I suggest that the reason that pumps seem to fail after ATF is added is because the system has been leaking and the pump has run dry. Power steering systems don't use up the fluid, they leak it. Most people don't check it unless the steering starts acting up or the pump starts making noise. Why would somebody need to be adding fluid unless it's leaking somewhere? The exception would be Ford pumps that just start making noise because they use bad pumps. Automatic transmission fluid and power steering fluid are formulated not to foam but most oils today don't foam too much either. 30 weight oil will work well if you don't use it in very cold weather. At 15 below zero, its almost a solid.
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