1960's P/S control valve

[Harry S.]

Last fall the P/S control valve in my 63 started leaking. The P/S functions of the car were fine, not too easy and not too hard to steer. This spring I came across an NOS period correct valve for the 63, same numbers, etc. The leaking has certainly stopped but the steering is too quick. The car can be stopped and with my pinky I can turn the steering wheel from stop to stop. At high speed it is equally as quick and probably dangerous if I move the steering wheel too quickly.

As far as I know there is no adjustment on the valve for this situation. I did change the hoses at the same time. Any thoughts?

Think I will rebuild the old valve and swap it out next spring.

[Joe L.]

Re: 1960's P/S control valve

Last fall the P/S control valve in my 63 started leaking. The P/S functions of the car were fine, not too easy and not too hard to steer. This spring I came across an NOS period correct valve for the 63, same numbers, etc. The leaking has certainly stopped but the steering is too quick. The car can be stopped and with my pinky I can turn the steering wheel from stop to stop. At high speed it is equally as quick and probably dangerous if I move the steering wheel too quickly.

As far as I know there is no adjustment on the valve for this situation. I did change the hoses at the same time. Any thoughts?

Think I will rebuild the old valve and swap it out next spring.

Harry-------

When you say "same numbers" do you mean casting numbers on the valve or adapter or do you mean an assembly part number found only on a GM box or parts tag? A control valve very similar to the Corvette valve was used on some pre-1963 passenger cars. The primary difference was one of the two internal springs. That spring affects exactly what you described.

[Harry S.]

Re: 1960's P/S control valve

Harry-------

When you say "same numbers" do you mean casting numbers on the valve or adapter or do you mean an assembly part number found only on a GM box or parts tag? A control valve very similar to the Corvette valve was used on some pre-1963 passenger cars. The primary difference was one of the two internal springs. That spring affects exactly what you described.

Thanks Joe, that is probably the problem. I'll swap the spring if I can find one. Have and spring PN's up you sleeve?

Cheers

[Edward J.]

Re: 1960's P/S control valve

Harry, Joe has hit the nail on the head later control valves used a different spring, to slow down the response due to radial tires, older control valves work on different pressure.

[Joe L.]

Re: 1960's P/S control valve

Thanks Joe, that is probably the problem. I'll swap the spring if I can find one. Have and spring PN's up you sleeve?

Cheers

Harry-------


GM #5687990. VERY difficult to find NOS.

This spring has 6 coils. The earlier passenger car springs have 3 to 5 coils.

[Timothy B.]

Re: 1960's P/S control valve

I could be wrong here but I think Edward is referring to something different in Corvette P/S valves than what Joe's post alludes too regarding the passenger car valve.

[Joe L.]

Re: 1960's P/S control valve

I could be wrong here but I think Edward is referring to something different in Corvette P/S valves than what Joe's post alludes too regarding the passenger car valve.

Timothy-------

Yes, I think he is referring to differences between the 1963-73 Corvette valve versus the 1974-82 Corvette valve. I don't know what the difference is relative to springs for these valves. I have several NOS examples of the 1963-73 GM #5687990 springs [none for sale]. However, the 1974-82 spring was never available in SERVICE. It was available only as part of the GM #7817308 valve assembly. This is the valve assembly less the adapter section. I have that, too, [not for sale] but I don't want to disassemble it to see what spring it includes. It might even be the same spring as the earlier valve.

In any event, the 1974-82 complete valve assembly (with adapter) replaced the 1963-73 for SERVICE. So, apparently, GM considers that the latter valve is perfectly acceptable for the earlier applications. GM NEVER specified the passenger car valves for a Corvette application.

[Joe R.]

Re: 1960's P/S control valve

Harry,

Do you have the original valve?

If you do why don't you just rebuilt it. Got a kit and it's yours if you need it.

JR

[Timothy B.]

Re: 1960's P/S control valve

If the earlier passenger car valve bolts up and works I would be curious what the difference is. Harry, I installed a complete P/S set up on my 67 from I believe a 77 corvette and I don't notice any difference from the unit on my 63. I will try to turn the wheels on the floor next time it's run but my thinking is the pressure to the slave cylinder is a function of the relief valve in the pump.

[Joe L.]

Re: 1960's P/S control valve

Harry,

Do you have the original valve?

If you do why don't you just rebuilt it. Got a kit and it's yours if you need it.

JR

JR-------


No kit I know of, NOS GM or aftermarket, includes the GM #5691581 or equivalent thereof annulus gasket. This gasket is the "Achille's Heel" of the control valves.

[Joe R.]

Re: 1960's P/S control valve

JR-------


No kit I know of, NOS GM or aftermarket, includes the GM #5691581 or equivalent thereof annulus gasket. This gasket is the "Achille's Heel" of the control valves.

Well Joe L., you better think again. If you have the old stuff from Saginaw you have the kits and also the GM 5691581.

JR

[Joe L.]

Re: 1960's P/S control valve

Well Joe L., you better think again. If you have the old stuff from Saginaw you have the kits and also the GM 5691581.

JR

JR-------


I don't think so. I have those kits but not where I can easily access them. In any event, the GM #5691207 is a ball stud kit. It does not contain the GM #5691581 gasket. The GM #5691150 is an adapter kit. It does not contain the GM #5691581 gasket, either. While you show a 5691581 gasket, it's not part of a kit. It's just as I said-----a separate part not sold as part of a kit.

[Joe R.]

Re: 1960's P/S control valve

Joe L.

I have everything here to rebuild a PS control Valve. And many more boxes of parts including the o-rings. Just send me a PS control valve and it will come back like new. I even have one body and piston assembly in the GM box.

Try it, you'll like it.

JR

[Joe L.]

Re: 1960's P/S control valve

Joe L.

I have everything here to rebuild a PS control Valve. And many more boxes of parts including the o-rings. Just send me a PS control valve and it will come back like new. I even have one body and piston assembly in the GM box.

Try it, you'll like it.

JR

JR-------


I didn't say that the valves could not be rebuilt. Most of the necessary parts are available in the aftermarket. I did say that I do not know of a replacement for the GM #5691581 gasket. This is a compression-type, metal gasket. If it's re-used, a leak will result.

[Timothy B.]

Re: 1960's P/S control valve

Joe,

Could it be that GM did not include the 581 gasket in the overhaul kit because they thought it was reusable.