Ok, I'm thinking to put a little extra caster in the frontend to make it less touchy at freeway speeds (toyota p/s box, ford pump). What does the stock axle have from the factory, Mid fifty says 2 deg and that you can go 4 deg. They make 2 and 4 deg shims...So anyone know the stock spec min/max and what they come with?.

 

I don't know what the stock specification for caster is on a straight axle but if it were my truck and I were going to increase the caster I'd go with the 4 degree shims. I once had a 32 Ford that had a full 12 degrees of caster built in. It went down the road straight as an arrow...but a bear to park! So, you really can't have too much caster.

Some of the twitchiness may be the pressure differential in the Toyota and Ford pumps. Have you checked into that?

 

The shop manual says min. 3 Max. 4.

 

Can you add as much as possible and add a flow reducer to the pressure line? You have to on a MII with PS and a GM pump

 

Rabbit trail - search "Borgeson 899001 to find the kit.

 

I haven't measured the pressure from the pump yet, but I would think that a '65ish ford pump would put out less pressure then a '85ish toyota 4x4 pump. That was the other thought was to put on a adjustable pressure reducer, I wanted to try the caster set-up first. But after reading the post about the aerostar, maybe I make a gauge to check the pressure first.