I have an 81 z/28 that has been giving me fits with power steering noise and aerating the fluid. I noticed the gear box is hot to the touch after running it a short time . This is the second set of lines and the second pump I have tryed, any Ideas?

It sure sounds as if you have a restriction somewhere in your system or you are somehow starving the pump for oil. You mentioned that you replaced lines and pumps. Is this problem the reason you replaced the pumps and lines or did the problem only occur after replacing them?

Does your system have a cooler in the return line. Is it possible that the cooler is damaged or a line kinked in that area?

Does your system have a remote reservoir leading to the pump? Is it possible that the rubber line from the remote reservoir to the pump housing is kinked.

When you originally replaced the pump and hoses, was the old fluid black and full of particles and gunk?

JIML82

Jim I bought the car after it had been sitting for several years, the gearbox had rags plugging the holes that the lines went into, the car was a project that someone abanded and I finished it. The first pump came with the car, I dont think it was the original pump though, I installed new lines,and drove the car for the first time. If it is driven easy it is fine but if you run the rpms up on the high side it pukes out the cap.So I swapped everything off my old 85 chevy truck , including lines, no kinks, and the problem is still there. I am useing a.t.f. in it and was wondering if that is too thin? I have used a.t.f. for years in powersteering though. Also I guess I cant answere your question about the fluid being burnt as the car was appart when I got it. Thanks Tom

Puking out the cap usually means air in the system that gets whipped to foam and expands to run out of the reservoir. Does the fluid look foamy when it pukes out? If your problem is just excessive air that needs to bleed out, it will take a little time but it will eventually make its way up into the reservoir and out. Once the air and oil turn to foam, you have to let the system set overnight and let the air combine into large enough bubbles for them to rise up into the reservoir.

I always recommend genuine GM power steering fluid, but ATF shouldn't be the cause of all of your problems.

I wonder if the gear may have gotten water down inside and possibly things like the rotary valve are rusted up.

BTW, just a small amount of water mixed in the power steering fluid will cause all kinds of noise and eratic power assist.

Jim

Are you running headers? Make sure that there is enough clearance between the header and the gear box. It sounds like the gear box is getting so hot and that it is causing the PS fluid to boil. This eventually is what is leading to the failure of the pump.

I dont think the heat off the headers or manifold does this. I have had both headers and rams horns that actually used to touch the box, with no ill effect.
Airation will becaused by a leak somewhere (air getting in) low fuild levels, or a restriction causing cavitation in the pump...maybe faulty pressure regulator (?)

I fixed the problem with a gear box replacement, it had to have gotten dirt or water in it from sitting all the years [inside] with only a rag over the holes. thanks for all your help. Tom