I have a 79 F250

Recently I noticed the steering seams to be skipping or not providing constant resistance during turning

Is this a sign power steering pump is going out?

It has generated a high pitch whine over time, but has always worked fine until recently.

I have anouther spare gearbox I was planning to use as a core for redhead but have no idea how to test a pump.

thanks

 

As an update; it has a lot of resistance when the wheel is straight but once you turn it the resistance goes away and it becomes very easy to turn.

 

2wd or 4wd ?

 

4 wheel drive

 

I don't know 2wd steering. If it's 4wd, I'd try bleeding it. If there's air in the pump, lines, or gear box it can have stiff spots. If there's a leak and the fluid level has gotten low, you could have air in the system. Obviously, fixing the leak first would be best. I've changed out three gear boxes and had trouble with air on the first one until I actually followed instructions:


Lift front end so that tires make no contact with the ground. With the engine NOT running, take the cap off the pump, place a large drip container underneath, have several bottles of fluid on hand. This is best done with two men. One man at the steering wheel, one at the pump with fluid. Fill the pump with fluid. Turn the wheel slowly from stop - stop, 20 times. Fluid will most likely come out of the pump. If there's air in the system, you'll get a lot of fluid coming out as the air bubbles come up. Keep pouring fluid in the pump. Never let it get low or the pump will suck air in again. Fill the pump, put the cap back on, then let the truck sit for at least 2 hours. Overnight is better. Repeat the process. Let it sit 2 hours. Do it again, except this time crank the engine, or run the pump with a drill if your engine isn't running. Be ready to pour fluid because as soon as pump starts turning, it could pull a lot of fluid down. The man at the pump should watch for air bubbles, and be very fast about keeping the pump full of fluid.

 

Have you checked the axle U joints ? Make sure they are not froze up, that can cause stiff spots. Unlock the hub. Turn the wheels either way, all the way.Then reach into the C's and try to turn the axle. If it doesn't turn free then you need a new one. If they are ok then jack it up and sit the axle on stands. Try turning the wheels all the way in both directions and see if there is a bind. If there is then you'll know it's a linkage or box problem.