Exactly. There is no residual hydraulic pressure in system once the engine is shut off so the free play is normal.
Power Steering Control Valve Play
Thread Starter
Drifting
Joined: May 2003
Posts: 1,979
Likes: 48
From: Lakeport CA
Power Steering Control Valve Play
Have a 77 in my shop, things appear tight in the steering box, and idler arm. New ball joints, probably could use some tie rod ends but I'm not really seeing any play there. I notice fairly quick movement of the pitman arm from the steering box when I rock the steering box input shaft. However. the power steering control valve input where the other end of the pitman arm connects moves what I feel is quite a bit to either side before the drag link begins to move.
With engine off, how much movement should be in that control box input area? Should it be able to swivel an inch to each side? Power steering appears to function without issue but I am concerned about what is "normal" amount of play in this area.
Thanks!
With engine off, how much movement should be in that control box input area? Should it be able to swivel an inch to each side? Power steering appears to function without issue but I am concerned about what is "normal" amount of play in this area.
Thanks!
Le Mans Master
Joined: Aug 2006
Posts: 7,426
Likes: 1,559
From: mount holly NC
2025 c3 ('74-'82) of the Year Finalist - Unmodified
2019 C3 of Year Finalist (appearance mods)
Are you talking about where the pitman arm connects to the power steering control valve?
Thread Starter
Drifting
Joined: May 2003
Posts: 1,979
Likes: 48
From: Lakeport CA
Yes. Car is up on a lift (4 post drive on), I reach up & turn the rag joint, pitman arm moves and the control valve arm (other end of pitman arm) moves quite a bit before drag link begins to move.
Le Mans Master
Joined: Aug 2006
Posts: 7,426
Likes: 1,559
From: mount holly NC
2025 c3 ('74-'82) of the Year Finalist - Unmodified
2019 C3 of Year Finalist (appearance mods)
Did the same test on my 74 and the ball connection in the valve moves about 1/4 inch total. 1/8inch left or right of center. That's normal.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
The 'play' in the ball stud on the P/S Control Valve is designed to be that way and must be so in order to work. That stud has a coiled spring next to it and the spring is connected to the shuttle valve in the control head. Movement of the valve signals the pressure to 'feed' the slave cylinder which results in powered movement.
In essence, applying force to the steering wheel puts pressure on that spring. When you quit turning the wheel, the spring relaxes and the control valve goes to 'center' position which removes any turning pressure from the cylinder.
That's the best I can do to describe how it works, but that 'play' in the control valve ball stud must be there if the system is to work as designed.
In essence, applying force to the steering wheel puts pressure on that spring. When you quit turning the wheel, the spring relaxes and the control valve goes to 'center' position which removes any turning pressure from the cylinder.
That's the best I can do to describe how it works, but that 'play' in the control valve ball stud must be there if the system is to work as designed.
Race Director
Joined: Jul 2001
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Thread Starter
Drifting
Joined: May 2003
Posts: 1,979
Likes: 48
From: Lakeport CA
I understand that some play is required & that is how the valve works (control is engaged). My real question is how much is normal & how much is excessive?
I did just check it again (as I am on site again)... Engine off the amount is 3/16 right & almost 1/8 left.
TIA.
I did just check it again (as I am on site again)... Engine off the amount is 3/16 right & almost 1/8 left.
TIA.
Le Mans Master
Joined: Jan 2000
Posts: 8,918
Likes: 27
From: New Hill NC
Forget it, its right.
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