Power assist booster

[Bob & Tracey]

We have been slowly improving the steering on our GMC 4101 (tie rod ends and a steering gear adjustment) and now it appears the the assist booster might need attention. With the engine not running there seems to be a lot of movement (1") at the booster cylinder control valve. I cannot find any information other than the valve spool`adjustment in the manual. How can I check this? Is it repairable? Is it time for a booster replacement? OR Is it time to upgrade to integral power steering???

Thanks,
Bob

[Slow Rider]

Bump

[JohnEd]

I only have the timerity to offer any info cause you don't seem to be getting ANY help.  And, I am not being critical of any of the experts.

In a manual system you can get almost all the slop out of the steering by closely adjusting the steering box's two main adjustments and making sure the mech links in the steering column have no play.  If that doesn't work you need a rebuilt box and or new units or sleeves or splines in the steering shaft.  You seem to have done all this.  In a conventional integrated PS system the sensing valve in integral to the PS box.  Still, while gently rocking the steering wheel you can verify that there is no p[lay but if you twist a little on the wheel you will feel some "give".  Looking at the box output shaft you will note that while the wheel moves some the op shaft doesn't seem to.  That is because the "valve" inside is flexing to open the hydraulic path to allow pressure to assist in the turning force.  You system is only slightly different in that that pressure assist is provided by an external "hyd assist" unit.  It still needs to move against a spring to "sense" the need and amt of assist.   Hense (great word), with the engine off you will just see what looks like "slop".  Start the engine and see if the wheels track the steering shaft input forces and the wheels start to turn immediately with the wheel.  Yours is and old time system and if the wheels are not turning there may not be any wheel movement. Drive it and determin that a small input of steer at the wheel does, in fact, give you a change in direction.

With the engine running look at all the components under the front end and verify that nothing that shouldn't be moving isn't when you rock the wheel back and forth strongly.  Caution....AIRBAGS.  Be on ramps of in a pit.  The only things left after that are king pins, bearing adjustment and bushings...any of which will destroy the steering if worn.   Wandering.....toe out.
HTH,

John

[bevans6]

Actually I seem to recall that Luke from US Coach offered some good advice that was lost when we lost three days of posts.  Maybe give him a call and have a chat?