Power steering 'conversion'

Apologies in advance - this post will be heavy on details to help out people in the future that want to upgrade power steering on a 1960-66 Chevy/GMC truck.  I couldn't find anyone that did it the way we did, and it cost us a few extra parts and trips to O'Reilly's.

Our GMC came with factory power assist steering that we really wanted to save to keep the originality.  We had already purchased 2" drop spindles and disc brakes from CPP, so we needed to use parts that worked with this kit.  If you use the original steering arm or a kit that attaches to factory tie rod ends at the spindle, you'll run into the same problems. 

Factory power assist uses the manual box with an added hydraulic ram. The pitman is different from the manual steering. On the GMC, there are no corners cut off the ram like you see in Nova's and Corvette's of the period.  Otherwise the setup looks to be the same.  There was a little play in the box, a lot of slop in the valve, and everything else was just worn.  The control valve and hydraulic ram parts are hard to find and expensive to rebuild.  We took it all out as one piece to note how everything fits.  The drag link looked to be in good shape until it was unscrewed from the control valve.  It's held in by a clamp that threads on to the drag link, ours had about 4 threads that weren't wiped off.  Not sure how this happened, but since this isn't replaceable or repairable, it pretty much sealed the deal that we would have to find a different option.

Everyone seems to be using the 68-87 power steering setup from GMC or Chevy trucks.  There are several key differences from 1966, including placement of the steering box, idler arm, and sizes of the tie rod ends.  We chose to use the adapter from CPP that fit well on our GMC.  You have to drill a couple holes, but that was cake.  We purchased a steering box, pump, and the drag link and associated parts out to each wheel for a 1987 GMC - as new as we could go since it's still 27 years old.  Or at least that was what the junkyard told us - the idler from a '75 model fit, '87 did not, according to what O'Reilly's book said.  But, they also had the inner tie rod marked as outer and vice versa.

First step is to cut off the end of the steering linkage including the coupler to the box.  The CPP kit comes with a double D end that has to be cut off to use the round bar.  I saw someone had ground the sides of the stock steering shaft to be able to use the double D section.  Clever idea I wish I though of first.  Next the steering box bolts to the frame, and attaches with a new rag joint, Dorman 31015.  Parts stores list 31011, which is for the manual box and too small.  The internet says this will work for the Jeep Grand Cherokee box in my Chevelle.

We set everything to point straight ahead, and welded the adapter to the steering column linkage.  You can also bolt or pin, but this would require drilling a hole and a tight fit on the bolt.  I trust my weld to be strong enough to keep everything solid.

The drag link and idler arm bracket need to match the upgraded steering parts.  The tie rod ends went to a larger size in '68, so make sure you get these parts for the swap.  I needed to drill new holes to mount the idler arm. Here's what I needed to connect everything up:

Moog K6143 Pitman Arm (73-87)

MasterPro K6096 Idler Arm (these changed over 73-87, so match it up)

66 Chevy/GMC tie rod end (right thread, inner I think)

Moog ES409LT tie rod end (left thread, factory 73-87 inner)

Custom adjustable sleeve - this has been the hardest part.

For the tie rod adjuster, call DCA Racing in LaCrosse.  Great guys, they were very helpful, knew exactly what we needed, and cheap.  Would have saved us tons of trips to the parts store.  Ask for:

Outer 5/8-18 right thread to Inner 11/16-16 left thread 

We asked for 5.25" long, 4.5" would have been better.

I powder coated them - but after tightening everything down I'm not quite sure why.  Probably have to hit with a rattle can after an alignment.  We set the steering wheel square, but noticed the drag link is shifted to the drivers side.  At some point we'll need to pull the wheel, square the front end, and put the wheel back on straight. Details for another day.

The picture above shows the new style idler arm in place, and below you can see where I drilled the holes. We used the updated idler arm, because the original uses a different size tapered joint.  To get the linkage straight, we lined up the drag link parallel to the crossmember, and set it level using my iPhone. The upper bolt is roughly even with the bottom of the large oval factory hole, and ~2" forward.  The bolt to the idler arm in the forward position is roughly in the same place as the forward joint in the factory set-up, so you could eye-ball off the factory idler bolts to get this close.  Obviously we haven't driven it yet to make sure it works, but nothing binds or hits as it sits.

And the final piece, sway bar from ~1985 Suburban.  Easiest part of the whole upgrade, just drill four holes in the frame and bolt it in.  The a-arms are already drilled for the factory brackets.

 

Cheap, no, but there is now zero play in the wheel and everything moves easy.  When we started it didn't even feel like the wheel was connected to the tires!

Oh, and don't forget to grease all the new fittings.