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Power Steering Control Valve (1974)
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Joined: Jul 2005
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From: Newfoundland
Power Steering Control Valve (1974)
Hi Gents
Looking four some clarification.... I've rebuilt the PSCV on my 74 Vette but am experiencing a very loose steering sensation.
With the unit reinstalled and balanced as per the manual, I noticed that when my son turns the wheel (with engine off) one way and then the other, from under the car I can see that the ball stud is moving about 1/4 inch either way in the PSCV. Is this normal? should the ball stud be stationary or is it supposed to move some?
Thanks in advance for your help!!
Looking four some clarification.... I've rebuilt the PSCV on my 74 Vette but am experiencing a very loose steering sensation.
With the unit reinstalled and balanced as per the manual, I noticed that when my son turns the wheel (with engine off) one way and then the other, from under the car I can see that the ball stud is moving about 1/4 inch either way in the PSCV. Is this normal? should the ball stud be stationary or is it supposed to move some?
Thanks in advance for your help!!
Racer
Joined: Jul 2013
Posts: 385
Likes: 3
From: Leesburg VA
I bought a new unit as mine was not rebuildable. I have it installed, but have not been able to run the car yet to run through the balancing routine. The ball stud on my unti is solid as far as any lateral movement is concerned. Being a ball stud, it will rotate around the ball, but any movement in the pitman arm translates directly to motion of the relay arm. There is no lateral play that needs to be taken up before the wheels turn.
So basically, what you are saying is that if the car was jacked up and the steering wheel was held stationary, you would be able to turn the wheels a little in each direction because of the play in the PSCV ball stud? I don't believe that is good, but I am no expert on PSCV. We need Jim to weigh in on this one.
I would send Jim a PM to get his take on it.
John
So basically, what you are saying is that if the car was jacked up and the steering wheel was held stationary, you would be able to turn the wheels a little in each direction because of the play in the PSCV ball stud? I don't believe that is good, but I am no expert on PSCV. We need Jim to weigh in on this one.
I would send Jim a PM to get his take on it.
John
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From: Newfoundland
Team Owner
Joined: Jan 2006
Posts: 37,637
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From: Crossville TN
In the P/S control valve the ball stud is spring-loaded so that it will have some motion when you are attempting to turn the wheel. That small motion is immediately translated in the control valve to direct high pressure oil into the appropriate side of the steering cylinder. Result: turning in that direction.
There needs to be some 'planned' movement in the system when you turn the wheel, so that the P/S system can sense what you want to do and then respond accordingly.
With no pressure in the system, it seems like there is a lot of 'slack' in the ball stud. As Mike Ward indicated, when the system is operating and there is significant hydraulic pressure in the control valve, the stud tightens up so there is little (if any) lost-motion in the system.
There needs to be some 'planned' movement in the system when you turn the wheel, so that the P/S system can sense what you want to do and then respond accordingly.
With no pressure in the system, it seems like there is a lot of 'slack' in the ball stud. As Mike Ward indicated, when the system is operating and there is significant hydraulic pressure in the control valve, the stud tightens up so there is little (if any) lost-motion in the system.
Racer
Joined: Jul 2013
Posts: 385
Likes: 3
From: Leesburg VA
Learn something new every day...god, I love this forum!
Now I need to go look closer at mine...
John
BTW...Jim is Jim Shea...he is a Corvette steering expert and hangs out here often. Look in any thread that talks about the steering column or box and he has probably chimed in. The dude know his stuff.
Now I need to go look closer at mine...
John
BTW...Jim is Jim Shea...he is a Corvette steering expert and hangs out here often. Look in any thread that talks about the steering column or box and he has probably chimed in. The dude know his stuff.
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Thread Starter
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Joined: Jul 2005
Posts: 58
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From: Newfoundland
OK, so i jacked the car up onto stands and gave this a test....
With the engine off, the ball stud moves about 1/4" each way in the PSCV.
With the engine running the ball stud is quite solid in the PSCV as you guys said it would be.
I was close to replacing the PSCV as I had the car in for an alignment and the mechanic pointed out the 'slop' in the PSCV and said that was a problem and until I had that fixed, the steering would continue to be loose.
Guess I need to find a new alignment shop now!! Problem is, I live in a small town and that was supposed to be the best shop in the area.
Thanks guys. I can always rely on the REAL experts here in the forums.
With the engine off, the ball stud moves about 1/4" each way in the PSCV.
With the engine running the ball stud is quite solid in the PSCV as you guys said it would be.
I was close to replacing the PSCV as I had the car in for an alignment and the mechanic pointed out the 'slop' in the PSCV and said that was a problem and until I had that fixed, the steering would continue to be loose.
Guess I need to find a new alignment shop now!! Problem is, I live in a small town and that was supposed to be the best shop in the area.
Thanks guys. I can always rely on the REAL experts here in the forums.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
The C3 power steering system is probably something that shop has never worked on....or, at least, has no 'operational' knowledge of. But, they might do a great job on alignments.
Next time you stop by that shop, go explain this system to them over a cup of their FREE coffee.
They will have a better understanding of how it works and, if they care at all, will appreciate you taking the time to bring them up to speed.
Next time you stop by that shop, go explain this system to them over a cup of their FREE coffee.
They will have a better understanding of how it works and, if they care at all, will appreciate you taking the time to bring them up to speed.