70 Challenger, factory power steering box, Saginaw pump. Had the box out to put in new seals in the shaft end. To get there the steering valve was pulled. All went back together smoothly with a few taps on the valve so the car not self steers.
Problem is that the steering now is way over-assisted - dangerously light with literally no effort needed to turn the wheels.
Something happened during reassembly, but what?
Any idea what causes over- assisting? Seems to me that nothing restricts the flow.
I also put in new o-rings between valve and gear box.

Here is some info I found on-line.

Note I have not tried this myself.

There was a how to in Mopar Action a few years ago, basically put a relief valve from a /6 in the pump, or shim it with washers.

I did the Mopar Action shim trick and it worked like a charm.
Made a big difference.

Thanks guys. Shimming the pump valve is a thing to try, but remember that this box was ok until I took off the steering valve to change seals om the shaft end. Has the valve and/or its spring something to do with this? Shimming the pump seems to be a bandaid only.

Maybe the P/S-box wasn't working as indented for all those years (internal leakage?) and now with new parts/seals it acts as 'new' again?
Getting a proper modern wheel-alignment will takeaway some of that 'over-powered' feeling too.

I only swapped shaft seal and o-ring at the steering shaft end. I do mye own alignments and it has 2 degrees positive caster (all that is in it), 0,25 neg camber and 1/16 total toe in on 235/70-15.

Did the shim fix on our 70 RT, I think I added two washers (from McMaster Carr) and we are pleased with the improvement.
Mind you, not exactly modern feel, but better.

Joe

Go back in see what got fubared when changing the seals on the shaft end.

when that article came out, i made a few spacers. [a benefit of being a machinist] i tried that mod on a couple of my buddies cars, and it worked good ! i made a selection of them in different thicknesses for my charger, but sadly, never got a chance to try them. my car has been off the road since 2006 or so.
another thing that helps the over-assist feeling, is a smaller diameter steering wheel. however, that is not an option for some.

RR: I can not see what could go wrong by changing ONLY the outer seals. But I wonder if the steering valve that hadde to come off has something to do with this. It is a spring and a valve pin in there. 12" steering wheel, 235/70 tires and big Block and the wheel will turn with only a touch from a finger.
What exactly does the steering valve do other than letting pressurized oil in? Does it meter the amount og flow too when the input shaft is turned? If so I suspect the valve is not moving as it should.

General I do not have an ans to your Q cuz I ain't into PS but I am strickly thinking of (KISS) Keep It Simple Sam, that something was moved/bumped/altered out of whack when those seals were changed.

RR: I am with you on that something came out of wack. I just can't see what. Those outher seals was changed by only removing the top retainer and cover and it was torqued to specs afterwards.

unless someone comes up with something specific I'd probably go back into it & checkout/go thru everything (assuming the over assist is a pain & it sounds like it is) & there could be a possibility that it will worsen or leak etc.

Yupp. The valve will come out first, but maybe more info find its way here till then.

Finally got the time to dig back in. Found that I had put one reaction spring retainer on the wrong side of the spring! All good now. Thanks for your replies!