Below Excerpts From -Power Steering Won't Return To Center Thread-
Originally Posted by HUH? 04-28-2006, 09:34 PM
For years modified 605 steering boxes were the only option for 55-57 Chevies. Everyone had the same complaints; no road feel (overpowered) and uncomfortable at speed because the box would not return to straight ahead.
No one ever found a cure for the problems. Tri five owners are converting to CPP's power unit based on 670 internal components and one that is 600 Saginaw based as well as power rack and pinion setups.
Originally Posted by Wrenches4hands 07-13-2006, 04:53 PM
...what about the power steering pump pressure? do you think it might just be providing to much pressure all the time.
You said you put the manual box back on and tried it with no problems. Well what about disconnecting the pump and drain most of the fluid from the pump, and then try it with the power box.
FORD used the Saginaw box a great deal in addition to the FORD box in the seventies. The suggestion of pump pressure makes sense as most current conversions (box and rack) call for the use of a Saginaw pump or a pressure reduction valve
which in turns seems to create the same problems, I would imagine due to decreased fluid flow resulting from trying to reduce the operating pressure of the FORD pump (whether EATON, THOMPSON or C-II).
FORD used this pump on the seventies intermediates and had to use the Saginaw pump for Hydro-Boost applications. This had to have something to do with pressure/volume.
The suggestion above calling for removing the assist feature (I would simply remove the drive belt) and seeing how the box performs while driving it without assist makes sense (make sure you have a double ration of Cheerios).
A problem such as this requires a diagnostic pressure gauge to isolate one system from another and to analize any problem within the system, whether assist or mechanical. The procedure is described in any seventies shop manual. You would have to research the required operating pressure of the origional box installation and then try to shim the relief valve in the pump to meet those specs it seems to me.
The above is just conjecture but it might be an option as it seems the vendor has no idea of what is going on (or does and won't own up to it) (one expensive recall).
Am Looking For Factory/Aftermarket Speed Parts For The MEL (MERC-EDSEL-LINC-TBIRD) Engine Family (383-410-430-462) Produced From 1958 To 1968
Also Early FORD Special Service Tools
-Mercury-Edsel-Lincoln Engine Forum