A few of you may remember my post back in late May or early June wanting advice on changing my '69 GMC 1 ton from manual to power steering. Here are a few notes if you ever consider this yourself.
1. The power steering gear has both a larger input shaft and a larger pitman shaft. So you need a 13/16 splined coupling for the input and a pitman arm made for a power steering gearbox. Nobody's parts books tell you that.
2. The splined coupling came off Ebay and Napa had the power steering pitman arm. According to the parts books, the pitman arm had to be for a '67 through 72. I only had to use the lower part of the splined coupling, I left the upper flange on the steering shaft and bolted the coupling to it.
3. I used a steering gear for a 1978 truck (The parts books say 1/2, 3/4 and 1 ton use the same steering gear) because I wanted to use a power steering pump and mounting brackets from a 1978 Monte Carlo. (All the other pulleys from the Monte Carlo were already installed on the 350 in the GMC. It was still sitting around from when the car was totaled in '86.) And I wanted to be sure the ends of the pressure hose would fit the pump and the steering gear.
4. Your power steering pump and steering gear have to be from pretty much the same year vehicle, GM changed to a metric size power steering hose fittings sometime after '78. (And from other experience, the metric return and pressure lines are different sizes on the steering gear.)
5. Napa had no problems coming up with the pressure hose for a '78 truck, but the Partsman claimed he could find no listing for a return hose for a 78 truck. I came home, got on my computer, searched NAPA online and they listed a return hose for the '78 truck. I called them with that part number and picked it up a day later. (So don't give up.)
6. I did have to modify two of the mount brackets to go around the exhaust manifold. (If you are familiar with GMC or Chevy, some of the early manifolds had the alternator mounted to the exhaust manifold and I had to cut the brackets to fit around the generator mount lugs on the manifold. I also had to make a spacer about 3/8" thick for one of the pump mount bolts in order not to have to install the Monte Carlo air conditioner bracket on the engine. I also had to notch the left bumper brace to clear the steering gear because it was larger than the manual.
When I finally had the right parts and brackets modified everything else bolted right up. I did have to come up with a fourth mount bolt for the steering gear, but the hole was already in the frame. The only snafu was I mounted the pump belt in the air conditioner groove on the engine pulley, and it should have been put in the rear groove where it normally goes. Working from the top you can't see that the back of the belt drags on the water pump pulley. So one more belt later I was good to go.
Its a dream to use in tight spaces now. And it doesn't wander back and forth going down the road like it did. That is why I changed it. Most times you could kinda steer the manual box toward the crown in the road but every so often it would dart to the left when the pressure got off the pitman shaft and it moved side to side in the gearbox.
So now just a million dollars worth of body work and some new paint and it will be good to go.
1. The power steering gear has both a larger input shaft and a larger pitman shaft. So you need a 13/16 splined coupling for the input and a pitman arm made for a power steering gearbox. Nobody's parts books tell you that.
2. The splined coupling came off Ebay and Napa had the power steering pitman arm. According to the parts books, the pitman arm had to be for a '67 through 72. I only had to use the lower part of the splined coupling, I left the upper flange on the steering shaft and bolted the coupling to it.
3. I used a steering gear for a 1978 truck (The parts books say 1/2, 3/4 and 1 ton use the same steering gear) because I wanted to use a power steering pump and mounting brackets from a 1978 Monte Carlo. (All the other pulleys from the Monte Carlo were already installed on the 350 in the GMC. It was still sitting around from when the car was totaled in '86.) And I wanted to be sure the ends of the pressure hose would fit the pump and the steering gear.
4. Your power steering pump and steering gear have to be from pretty much the same year vehicle, GM changed to a metric size power steering hose fittings sometime after '78. (And from other experience, the metric return and pressure lines are different sizes on the steering gear.)
5. Napa had no problems coming up with the pressure hose for a '78 truck, but the Partsman claimed he could find no listing for a return hose for a 78 truck. I came home, got on my computer, searched NAPA online and they listed a return hose for the '78 truck. I called them with that part number and picked it up a day later. (So don't give up.)
6. I did have to modify two of the mount brackets to go around the exhaust manifold. (If you are familiar with GMC or Chevy, some of the early manifolds had the alternator mounted to the exhaust manifold and I had to cut the brackets to fit around the generator mount lugs on the manifold. I also had to make a spacer about 3/8" thick for one of the pump mount bolts in order not to have to install the Monte Carlo air conditioner bracket on the engine. I also had to notch the left bumper brace to clear the steering gear because it was larger than the manual.
When I finally had the right parts and brackets modified everything else bolted right up. I did have to come up with a fourth mount bolt for the steering gear, but the hole was already in the frame. The only snafu was I mounted the pump belt in the air conditioner groove on the engine pulley, and it should have been put in the rear groove where it normally goes. Working from the top you can't see that the back of the belt drags on the water pump pulley. So one more belt later I was good to go.
Its a dream to use in tight spaces now. And it doesn't wander back and forth going down the road like it did. That is why I changed it. Most times you could kinda steer the manual box toward the crown in the road but every so often it would dart to the left when the pressure got off the pitman shaft and it moved side to side in the gearbox.
So now just a million dollars worth of body work and some new paint and it will be good to go.
