I just replaced the power steering slave unit on my 79 - the PO cut the old one out and threw it away. When I started it up, the wheels pulled to the left about 15 degrees and stayed there - no way to even muscle them back to straight. Had to pull off the belt to get it back in the garage. Question: Is this a normal occurance before bleading the system of air? According to the assembly manual I put the hoses in the correct locations, just really surprised at the result - not to mention how much I panicked when the wheels turned left while still on the ramps. Keep getting surprises like that and I may have to taking up drinking beer. Thanks.

 

vavle may is not balanced. be glad you didnt have your arm in the steering wheel when you started the car. you would have a nice cast on your arm we could sign.

 

Lucky for me - never had a cast before and don't want to start at my age. I haven't seen anything on balancing in the shop manual, any idea on how it is done? thanks.

 

I think from my knowledge of hydraulics you must first determine where the problem is by isolating parts of the system. I think the slave cylinder piston seal is blown, or you have 2 hose in the wrong ports. I suggest disconecting the end of the cylinder connected to the steering linkage, and check to see what reaction you get. While you watch have someone turn the steering wheel to see if you get movement, and go from there. Double check every thing you have done already. Also when you installed the new valve did you center the steering wheel? Did center the valve, by turning it from stop to stop. If not I would start here.

Good Luck!!!

 

I had a simular problem with a--oh my god--Mustang. The hoses were switched. Also check that the valve center adjustment is correct. Alot of rebuilt parts are junk. Buy a new one if you can. Good luck.

 

This is a paper by Jim Shea. He is the steering gear guru here on the forums. It can be found on this page.

http://www.corvettefaq.com/listing.asp?group=7

Last Revised 18AP2005

REPLACING AND BALANCING THE POWER STEERING CONTROL VALVE

The purpose of this paper is to provide some helpful hints when replacing and/or balancing the Corvette power steering control valve. There are two pages from the Chevrolet Chassis Service Manual that should be included with this paper. They are pages 9-34 and 9-35. They have been scanned and are provided as word documents; <http://www.corvettefaq.com/c3/ValveReplace&BalancePic1.doc>
<http://www.corvettefaq.com/c3/ValveReplace&BalancePic2.doc>

A Word Of Caution: It has come to my attention that some new replacement control valves have been very poorly balanced. Starting the engine with a very out of balanced valve can result in the steering system self steering without any steering wheel inputs. Some steering systems have been known to “whip” the steering wheel all the way to full lock. The assist cylinder (or ram) can develop up to 1700 pounds of force. So an out of control power steering system is nothing to mess with! Therefore, as part of this procedure, I strongly recommend that you disconnect the assist cylinder from the frame before ever starting the engine.

Removal
Follow the instructions as outlined on page 9-34. One note of clarification: The relay rod to control valve clamp bolt is the bolt that goes in the tapped hole on the extreme left end of the valve as shown in the picture labeled fig. 69. It is NOT the bolt with the arrow in that picture.

A hint: Count the number of revolutions it takes to remove your original valve from the relay rod. Screw the new valve on the same number of revolutions. This should result in your steering wheel being fairly closely centered when the car is going straight down the road.

Since you are already under the vehicle, now is a good time to disconnect the assist cylinder from the frame attachment.

Installation
As described in 9-34, with the new valve installed and the system filled with power steering fluid, the system now needs to have air eliminated from within the fluid circuit. I have a slightly different procedure than described for bleeding this air.

My procedure for air bleed and control valve balance check.
After you have reattached the valve and all the hoses, fill the power steering pump reservoir to the proper level and let the oil remain undisturbed for a least two minutes. DO NOT start the engine! With the both front wheels off the ground, turn the steering wheel lock to lock at least a dozen times. If the car is on jack stands be sure that your wheels don't hit the stands at full lock! Now check the fluid level, add fluid if necessary. Again, turn the steering wheel lock to lock several times.

Valve Balancing
With the assist cylinder disconnected from the frame, you can now start the engine and check the valve balance as described on both pages 9-34 and 9-35 under Valve Balancing (2.a., b., 3., and 4.)

If you determine that you need to tweak the valve balance, remember that the nut that you are going to adjust is a torque prevailing type. You will note that the instructions say that you are not to turn the nut more than absolutely necessary in order to balance the valve. It has been reported that some rebuilt or remanufactured valves have had this nut loosen and the valve goes out of balance when the nut backs off. If the nut seems to rotate fairly freely, you should consider either a new torque prevailing nut or loctite it in place.

One Last Check
After you have completed the valve balance procedure and the vehicle is now on the ground, check the power steering fluid level one last time and refill if necessary.
If the power steering oil appears milky or foamy, allow the vehicle to stand for a few minutes and then start the engine. (If there is entrapped air in the power steering system, you can experience the following short term problems: loud steering pump noise when steering; lack of power assist; poor returnability.)

Turn the steering wheel back and forth to full lock a few times. Only bump the wheel stops lightly and very briefly. Sometimes it may take a short drive of about 10 miles and/or the vehicle sitting overnight to finally get the remaining entrapped air out of the fluid.



JIML82@aol.com
ValveReplace&Balance18AP05.doc

BigBlockk

Later.....

 

Thanks very much for the help. The slave cylinder is brand new and as far as I can tell the valve is probably the original. Luckily it is supposed to be in the 60s tomorrow - good work day.

 

From you description of the problem, it sures seems to me that you have the two valve to assist cylinder hoses reversed. They should criss-cross where they attach to the valve.

The following is a scan from a C3 AIM:

http://www.corvettefaq.com/c3/StrgHoseValvetoCylPic.doc

Pay particular attention to VIEW A.

Jim Shea

 

Jim, thanks. I did cross the hoses (used the picture in the assembly manual) so I ruled out that problem. I just pulled down the info on balancing the valve and will try that this afternoon. I'll let you know how I make out. Thanks for all the help.

Chuck

 

By the way Jim, I hope you don't mind me copying your page but I knew you did one on balancing the valves and I didn't want to have to retype the whole thing.

BigBlockk

Later.....

 

Thanks to all - paper and pages on balancing made it a walk in the park. Turned over the engine and the piston shaft pushed all the way out. Must have been really out of adjustment because I was turning and turning and just about ready to give up and replace the valve when, lo and behold, the shaft started going back in. A little of fiddling and was able to move it in and out by hand. Test drive was uneventful and everything seems to work. Once again, thanks for all the help.

Chuck

 

Glad you got it worked out. Supposedly these things are balanced when they are shipped to you.

 

The valve was already in the car. PO cut out (with a sawsall) the cylinder. He didn't want power steering so this was his solution.