Everyone seems to be counting their pennies these days, which translates into less money available for automotive repairs. In the case of our '76 Corvette, it was the car's power-steering unit that needed attention. The system worked fine when the wheel was turned left, but really had to be muscled in the other direction.
We decided to enlist the help of Jim Phillips Automotive, whose techs walked us through the diagnostic process they would normally employ in a case like ours. In the pages that follow, we'll show you the steps behind that process and provide you with all the information you need in order to make the necessary repairs yourself.
These are all the tools you'll...
These are all the tools you'll need to complete the job. As you can see, there's nothing exotic involved.
If thoughts of a redlined bank account are flashing through your mind at this point, don't worry: We'll be keeping the project as affordable--and as straightforward--as possible.
Our first step was to make sure the power-steering-fluid level was within range. With a low fluid level, the pump can suck in air, causing noise and a loss of power assist. We kept our fingers crossed that this was the case, but when we checked our Vette's reservoir, it wasn't even a drop low.
Next on the list was to check the operation of the power-steering pump. We did this by revving the motor and then attempting to turn the steering wheel to the right. Had the elevated revs made the wheel easier to turn, it would have been a good indication that the pump was faulty. They didn't, so we crossed the pump off of our list of suspects.
All of the belts were checked and found to be at the proper tension. By now we knew the belts, the power-steering pump, and fluid level were all in fine shape. The next step was to check the steering rack to see if it had a bad valve or was over-packed with grease.
With the car lifted, we tried to adjust the steering by turning the adjusting nut with the engine running. The nut is located on the end of the power-steering control valve, under a cap. (Note: Exercise caution while doing this, since even a small adjustment can cause the steering wheel to twist violently in your hands.) Adjusting the nut had no effect on our car's steering.
At this point, it was apparent that the control valve wasn't functioning properly. We elected to go with a new valve, since it was less expensive than purchasing a rebuilt unit. The valve came with a new bolt, a new cotter key, and a castellated nut for the pitman arm.
Replacing the control valve...
Replacing the control valve may seem daunting at first, but the job is actually much easier than it looks. Besides, your new valve (bottom) should come with an instruction manual that walks you through the entire installation procedure. Money you'll save by doing the job yourself: around $500.
First, remove all of the hoses...
First, remove all of the hoses that go to the control valve. It's very important to mark which hose goes where. We used chalk marks to keep them straight.
Have a bucket at the ready,...
Have a bucket at the ready, since steering fluid will begin draining out as soon as you disconnect the hoses.
It's now time to remove the...
It's now time to remove the control valve. First, it needs to be removed from the pitman arm. Reach around to the back of the valve to find the cotter pin. Remove it, followed by the nut. If you don't have a pitman puller, you'll need to use a pickle fork and hammer to break the tapper.
Next, remove the threaded...
Next, remove the threaded bolt from the center link and unscrew the control valve.
When reinstalling, it's important...
When reinstalling, it's important to note that there's a notch on the center link where the bolt screws back in.
With the old control valve...
With the old control valve removed, it's time to install the new one. To accomplish this, simply reverse the removal process.
Now that the new valve is...
Now that the new valve is installed, you need to make sure it's set up correctly. The valve we received from Lonestar Caliper was already greased from the factory.
Once everything has been reinstalled,...
Once everything has been reinstalled, it's time to add fresh power-steering fluid. Do not reuse your old fluid, as it may contain contaminants that could cause leaks or even void the warranty on your new parts. You'll need to keep adding fluid to the reservoir after the car has been started.
If the piston rod on your...
If the piston rod on your car moved when you fired the engine, adjustment is needed. First, double-check to make sure the steering wheel is straight. If the rod retracted when the motor was started, you need to adjust the nut clockwise. If the rod extended, you need to adjust the nut counter-clockwise. Next, turn the nut in the opposite direction, counting the turns until the rod begins to move. You'll need to turn it back in the other direction half as many times to get it centered. This may take some trial and error. Just make sure the slave-cylinder piston rod is disconnected while adjusting and don't perform any more adjustments after the piston rod is reconnected. Once everything is reattached, and the car is on the ground, start the car and make sure the wheels don't move. Keep your hands away from the steering wheel, just in case your adjustments were off.
The valve should come already...
The valve should come already adjusted so that the car's wheels are straight when the engine is started. If not, the wheels can swing hard to the right or left when the motor is cranked for the first time. Because of this, it's recommended that you disconnect the slave cylinder's piston rod from the framerail bracket. That way, you can watch to see if it's centered and determine whether adjustments are necessary.
Start the motor and watch...
Start the motor and watch the piston rod. Ours was set up correctly, so no further steps were required. We reconnected the piston rod to the frame bracket, topped off our power-steering fluid level, and were ready to roll.