My 81zx NA has a manual rack, and at low speed and in the parking lots there is a pronounced groan when I crank the wheel. I think its in the column, but I dont want to take it apart until I have a better idea of what I need to replace and where to get it.

 

Y'know, I've got a similar problem on my power steering '82... It doesn't happen all the time though, usually just when I'm cranking the wheel a fair amount quickly, such as when maneuvering in a parking lot.

 

Hear Rave, Check your PS fluid. A low reservoir can cause the pump to make the noise you're describing. jm, I'd get under the car and check all the bushings, ball joints and tie rods for wear or damage. If the sound IS coming from the column then your steering shaft may need to be greased.
You can also buy a cheapo grease gun and grease all the suspension and steering fittings. That may help your problem if they haven't been lubed in a while.

 

Most all 1981 models had full power steering systems. The other years had power assist racks. The racks use Automatic Transmission Fluid in the power steering resivour. Yours might be the same.

The grumble is usually due to low fluid.

 

My power steering pump started making noise about a year ago. I looked into replacing it or rebuilding it. Even with my hook-ups I was shocked at the cost. I changed the fluid and added a bottle of "Lucas" power steering additive and the noise completely went away. That stuff is magic. Most additives aren't worth the drive down to the auto parts store to get them, but that Lucas really is awesome. It will work equally good wether you have a gearbox or rack and pinion. Been using it at the shop for years. One thing about the Z... while some parts are plentiful and cheap, other's are rare and insanely expensive. P/S pumps, gearboxes, A/C Compressors in particular are going for outrageous prices for some reason, but you can still get an oil pan gasket for $6.75 at Kragen... go figure.

Rod.