Steering Box Bench Racing

Since we've gone so far with the front suspension I decided to do the last piece and replace the steering box with a quick-ratio unit. This upgrade is pretty popular with anyone with a GM 60-70's era muscle car and our 1973 Nova was ready for a steering box upgrade. Quite a few folks have said this was the best upgrade they did to their suspension.

The replacement steering box of choice is the XH code from the 85-93 IROC Z-28. But you can see from this chart there are quite a few fast ratio "junk yard" options. The differ in their T-Bar size which changes the steering effort. High effort is a preferred setup as it gives you more feel for the road.

Instead of a 30 year-old junk yard unit or a $400 AGR unit, I opted for a Cardone 27-6550 remanufactured unit. These can be had for about $150 at your local auto parts store. I got my from O'reillys. This box is 2.5 turns lock to lock vs the 4 turns in my stock box. The argument against using one of these is you never know if you are getting the "high effort" internals or a low effort unit. Since we are not Auto Crossing this car I wasn't real concerned. The steering on the Nova is already pretty heavy with the addition of the tubular A-arms and 4 degrees of caster.

 

Since I knew I had to grind off a chunk of the box to clear the header and the paint on the Cardone unit is pretty bad, I decided to strip and repaint the steering box with caliper paint. The 4 bolt top cover is actually aluminum so I left that natural.

In addition to the box, I needed a set of Lee inserts. The inserts with an installation tool were $25 shipped. These little aluminum pieces allow you to run this o-ring style box with the old flare style fittings on the 1973 Nova power steering hoses. Of note is the fact that the steering box has metric threads and the hoses are SAE but they are an almost exact match so they thread right up.

I put the Lee inserts in the freezer overnight and they tapped right into the steering box. You can see in the photo below I left in the pressure check ball in the box. Some of the Auto-X guys will remove the check ball to allow more flow.

You can also see the "chunk" I took out of the steering box to clear the headers. This had already been done to my old box so I just followed its pattern.

The last piece of the puzzle is the Lares #200 rag joint. This was ordered from Rock Auto for $25 shipped and it allows me to mate the (more) modern steering box to my column. All in all this project is just over $200 in parts.

Parts List 
Coupler (Rag Joint) (GM  7818568, Dorman 31011, Lares #200); Quick Ratio Steering Box (Cardone 27-6550, Duralast 6561); Lee Inserts; GM Power  Steering Fluid.

Removal of the old Box
The first step was to pull out the old box. I've read that guys have done this swap in 3 hours. After all there are just 3 bolts holding the box in place... right? I decided to go with the slow but steady method.

First I loosened the lug nuts on the passenger front wheel and jacked the car up and put it on jack stands. Then I removed the wheel and un-bolted and removed the inner fender well. Next I removed the header and then I removed the castle nut that attaches the Pitman Arm to the center link. I didn't have a pickle fork and was planning to reuse my Pitnam Arm, so in order to get a gear puller on the Pitnam Arm, I needed to remove the disc brake and unbolt the steering arm from the spindle. This allowed me to swing the tie rod out of the way and get my gear puller on the Pitnam Arm ball joint. Finally I unbolted the two nuts on the rag joint and unbolted the 3 bolts on the steering box.

This removal took a lot longer but if I had left the fender well in place this would have been back breaking and knuckle busting. Instead it was a nice Sunday project. Here's the greasy old parts.

I am reusing the power steering pump so I stripped it as well and repainted it and the bracket with Chasis Black. Here's the finished product after some clean-up and a new coat of paint. All ready to go back together.