Hydro assist help

tsconver

Well-Known Member
Joined
Nov 3, 2007
Location
Durham, NC
I recently ported my steering box and added a 1.5" psc ram. It works great locked and in the rocks. However on the street it is very squirrely. Just a small.inpit and it wants to turn hard.

Is this normal? Is there anything I can do to make it more stable at highway speed? It is not safe right now on the road.
 
You could put a larger diameter ram on it to slow it down...or just get used to the steering.
 
How much caster is in it? I'm not sure what box comes in the WJ's but being an 03 I'd assume a Mercedes box? If so they're known for being twitchy compared to the older Saginaw boxes. The Mercedes boxes have some large pressure cavities which means more flow. As @Croatan_Kid pointed out a larger ram will slow it down some.

Thicker torsion bar in the box for less power assist

Huh? Can you elaborate for knowledge sake?
 
You can try to orificed fittings to slow the oil down.

Mine was twitchy like that until I adjusted the caster as mentioned.
 
Definitely easiest is to use a larger diameter ram to slow it down some.

At some point, the limit in hydro assist is the return flow path thru the box. Many of these are around 1/8 diameter hole at several inches long.

This will “feel” like the steering won’t respond to quick back to back inputs. Just a heads up on that. That flow path acts like an orfice tune to the whole system. Until that occurs you change things around to how you like them.

Krc also offers a pump with an outlet fitting that is easily changed with different orfice sizes for different flow values.

As far as the torsion bar and servo inside the box:

Some boxes are built in a way that you can change the torsion bar inside the servo. Changing this dictates the feel of the steering.

A smaller diameter bar will feel easier to turn,

While a thicker bar will feel heavier to turn.

The thicker bar feels less twitchy than a thinner one.

The torsion bar changes the power input to the system based on difference between the box position and steering wheel position.

The more the bar is twisted inside the servo, the more power(quicker) is applied to the assist.

Yes definitely make sure all the basics (caster, throw, Pittman/knuckle ratio) are in order first.
 
Did you modify the relief or drill the valve out on the pump?
 
Pump is modified. Pump and gear are for redneck ram.

You can slow the oil down with a smaller hole in the pump valve if you have another to play with
 
I would agree with the ram diameter slowing it down. I just put a 2.5 ram on my CJ and modded the pump and it steers great.
 
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