67 PS Control Valve?

[Bill Becker]

Last fall, after centering the control valve on my newly restored 67, I noticed that while turning the steering wheel to the left, the wheel would literallly take off by itself at about 1/4 turn from lockup. This was with so much force that you wouldn't want your arm in between the spokes. It turned normally to the right, but when you turned to the left, steering was normal except when you got almost to lockup the steering would turn by itself, and you could tell the pump was straining as it would lower the rpm of the motor and the belt would squeal. You couldn't physically move the steering wheel to the right until the motor was stopped and the pressure would subside. Now, all components were either rebuilt (steering sector) or new rebuilt parts (control valve and ps pump). I've had the front and rear aligned twice, (that's another story) and it drives OK, just when the wheel is turned to the left almost to lockup.

I called Muskegan brake and explained the situation to which they supplied me with another rebuilt control valve. Well, I just got around to installing the new one, and guess what, it does the same thing! I'm thinking the problem may lie elsewhere. Any suggestions?

Thanks,
Bill Becker

[Gary S.]

Re: 67 PS Control Valve?

Bill, from my reading and not from practical experience, the description you provdided sounds exactly like a control valve that needs to be readjusted for centering. When my buddy replaced his control valve and started the engine up for the first time, there was a definite surge of the steering wheel that he says would have really done some damage, had his hand been through the spokes.
Gary

[Gary S.]

Re: 67 PS Control Valve?

Bill, from my reading and not from practical experience, the description you provdided sounds exactly like a control valve that needs to be readjusted for centering. When my buddy replaced his control valve and started the engine up for the first time, there was a definite surge of the steering wheel that he says would have really done some damage, had his hand been through the spokes.
Gary

[Jack H.]

Re: 67 PS Control Valve?

Corvette control valve was DIFFERENT from equivalent passenger car and typically marked with an 'X' on the adjuster dust cap to visually ID the part. Internally, some control/return springs have unique to Corvette spring constants which is documented as a note in the applicable shop manual and/or Chassis Service Manual.

I don't know how your supplier is rebuilding the control valve, but if it's being assembled as 'one fits all Chevy', this might be part of the problem. You sure should be able to 'null' the overcenter adjustment using the proceedures called out in the applicable service manuals....

[Jack H.]

Re: 67 PS Control Valve?

Corvette control valve was DIFFERENT from equivalent passenger car and typically marked with an 'X' on the adjuster dust cap to visually ID the part. Internally, some control/return springs have unique to Corvette spring constants which is documented as a note in the applicable shop manual and/or Chassis Service Manual.

I don't know how your supplier is rebuilding the control valve, but if it's being assembled as 'one fits all Chevy', this might be part of the problem. You sure should be able to 'null' the overcenter adjustment using the proceedures called out in the applicable service manuals....

[Joe L.]

Re: 67 PS Control Valve?

Bill-----

I would say that your problem is in one of 3 areas:

1) valve not properly centered;

2) either the retract or extend hoses (the 2 that go to the hydraulic cylinder) is kinked or otherwise plugged;

3) the retract and extend hoses are reversed

[Joe L.]

Re: 67 PS Control Valve?

Bill-----

I would say that your problem is in one of 3 areas:

1) valve not properly centered;

2) either the retract or extend hoses (the 2 that go to the hydraulic cylinder) is kinked or otherwise plugged;

3) the retract and extend hoses are reversed