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Power steering pressure valve
Posted 22 November 2010 - 02:52 PM
My Vanagon w/ EJ22 has always had minor problems with the power steering and I set about to fix that a month ago. The stock Vanagon pump put out 1500 PSI and the EJ22 pump only 1100 PSI or so. There is a spool valve inside the pump that controls the pressure. This valve is easily removed by unscrewing everything at the pressure port on the pump and gently pulling out the valve with some pliers. This spool valve has an internal ball and spring, and by shimming the spring I bumped up the pressure and my steering was great!
So with that experience I decided to fix the Subaru's pump. The EA82 pump is a bit different, the spool valve is in the same place but of a slightly different design. It does not have a ball and it looks like a less precise design. But in any case it has a spring that controls the pressure, it's behind the spool valve. I pulled out the valve and the spring and measured the free length. It was about 28mm long; I stretched it out to about 38mm and put it all back together. All the o-rings were hardened so I put new ones in too. The pump does not need to be removed to do this, but the pulley nut needs to be loosened to get the socket wrench over the pump outlet port.
Well now it's great too! So if you have problems with your power steering when making quick turns, like auto-x or playing around on wet roads, you should give this a try.
Posted 02 October 2012 - 05:21 PM
The spool valve is a bit different than the EJ22; instead of being threaded together it's pressed together. There is a little screen on one side held with a wire clip, and then a plug pressed in to hold the spring and ball valve.
The stock depth of this plug is 5.75mm. A couple taps with a punch and now it sits at 7.25mm deep. Easy as that, no shims needed. I noticed the added response this morning just pulling into my parking space.
Posted 03 October 2012 - 09:57 AM
My EA81 sedan the power steering is off the chain.....I mean it's too powerful, and there is no "neutral" feeling.
One finger flick will spin the wheel to full lock. It's twitchy/touchy, and it's put me in the ditch on my way home (gravel roads) because there is no centering action.
It reminds me of one of those old style racing video games where you spin the wheel continually round and round when you want to turn.
Press? what do you think?
Posted 03 October 2012 - 10:13 AM
Posted 03 October 2012 - 11:55 AM
there is no centering action. <...> Press? what do you think?
Sounds like you need more caster. The EA81 (and to some extent the EA82) seem to have alignment specs targeted for manual steering. This means little caster and positive camber. But when fitted with power steering it's too much.
The spool valve in the pump has a lot of hysteresis - it allows full pump pressure until you exceed the valve pressure, and then the pressure is reduced significantly. It keeps from squealing the belt and blowing hoses. If you were to reduce the valve's operating pressure, it would not feel very good. Basically your power "assist" would briefly cut out and be almost like manual steering. This is how my steering felt on quick turns before my valve mod.
The ideal way to reduce the actual assist is to change the stiffness of the torsion bar inside the steering rack control valve. That's obviously difficult. An easier idea is to introduce a small orifice on the outlet of the pump. There should be an orifice in there somewhere, maybe you can weld it closed and drill it smaller.
Posted 27 March 2015 - 01:54 PM
bringing this back to the top. I want to modify an EJ pump for my power assist on Subota. Did you happen to get any pics of this Presslab? And what is your guesstimation of increased PSI on the EJ unit?
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