My power steering is too powerful
We have a 1939 Plymouth with a Mopar engine and we’ve added power steering to the car from a 1997 Dodge Dakota. The steering turns easily without resistance, in fact, a bit too much so. It is now so responsive that it feels a bit dangerous. We’ve decreased the power steering pump pressure, but that didn’t help. Any suggestions?
You don’t state how much you’ve decreased pump pressure or what method you used to decrease it but decreasing pressure is the usual way to reduce the level of power steering assist. You may need to simply reduce pressure further. You have to be careful, however, not to reduce hydraulic assist fluid volume significantly because to do so may result in partial or complete loss of power assist. This is why it’s a bad idea to replace the stock pump pulley with a larger diameter pulley.
The easiest way to reduce pump pressure safely is by adjusting or changing the power steering pump valve. A qualified pump rebuilder can do this for you, or you can do it yourself. Various parts providers can sell you a new valve or the parts needed to adjust the valve you have, including Bill’s Hot Rod Co. in Covina, California (billshotrodcompany.com), which sells a power steering flow valve adjusting kit for about $18.
I am not familiar enough with the exact steering setup that’s in your car but something else worth looking at is the geometry of your linkage and suspension. You may be able to move the attachment points for the steering rack or tie rod ends to change the effort required to steer the wheels.
In a similar vein, your car’s wheel alignment will impact the feel of the steering and the effort required to turn the wheels. In particular, the wheel caster can increase or decrease steering effort required. Caster is the angle at which the steering pivot axis is tilted forward or rearward from absolute vertical, as viewed from the side. If the pivot axis is tilted rearward with the top pivot located farther rearward than the bottom pivot then the caster is positive. If the top is tilted forward relative to the bottom then the caster is negative. In general, greater caster angles improve straight line stability but also increase steering effort. Check your caster and if feasible, increase caster angle to increase steering effort.