Good morning! I posted this thread yesterday but got no response so I thought I would try again. The other day the my truck (78 f150) 4X4 wouldnt start, so I had some help pushing it around the corner. After I got it started the power steeing stopped working. No power steering, just intermitenly. I thought something might have happened to the pump so I replaced it but still not power steering. Did I do something to the gear box? The lines appear to be clear and not blocked, but need some help

 

If you figure it out-let me know- I have the same issue. I have a 79 4X4 that I am doing a restoration on. I replaced the steering gear box and lines and refilled the pump. It seems I only have power steering intermittently- better to one side than the other. If I take the weight off the front end it seems to work normally. I have heard that you need to turn the wheels all the way to one side and then to the other after replacing the pump to kind of get the air out of it, but this did not help.
Let me know what you find out.

 

The only fluid I have noticed is that it seems to be bubbling out of the top of the pump. Although the low pressure seems to have a small leak, but nothing that would cause no power.

 

This has to be part of Ford's grand design. Yep...we had the SAME problem when I replaced the gear box LOL.

Ours is now working normally. Here's what we wound up doing. It might help? But we had to replace a week later the pressure hose for the correct one. The fluid was extremely foamy after replacing the gear box and several attempts at purging the system of the extra air. So we tried a different tact at refill and purging air. We put the hoses back on (the new one) and I disabled the ignition. I refilled the pump and had my wife crank the engine over for several seconds. I then refilled the pump again and did the same thing a couple more times. After the fluid level appeared to be normal? I gave it a final topping off, and turned the ignition back 'on' and we started the truck and ran the steering L/R several dozen times. I wound up using a suction pump on the p/s pump due to overfilling LOL... But it seems that the pump running at an extreme slow speed can purge the air out much better then having the engine running. It does not spin the pump fast enough to really foam up the fluid, but it does allow the air to bleed out.

It would appear that a slow spin on the pump allows for better air purging out of the system. If the fluid in the system is all foamed up? The system reacts with major 'valve control' issues. Spotty power steering...works in one direction and not the other..etc.. Any dirt or crud can also bung up the works. (in other words...a good flushing out with a line disconnected and just letting the engine spin on the starter for a few seconds at a pop wouldn't hurt)

S-

 

Well I will try this. So do you think its more of any air in the system than a gear box issue.

 

Either air or something is bunging up the control valve action in the gear box. In any event? It's always a good idea from time to time to flush out the power steering fluid and replace it with new. It won't hurt anything by doing basic maintenance on it.

S-

 

Thanks for the help. I will do some checking on it tonight. Being a brand new pump and fluid, i figured i was good. I also flushed the lines when I put the new one on. I have noticed that the high pressure line is a little loose, but not leaking. I will replace this also and go from there.

 

I just replaced my pump on my 78 & used the method Tedybear mentioned. It seemed to work without any problems. I actually read the instructions that came with the pump and it says right in there to do it this way. I always thought that paper they stuff in the boxes was for wiping you hands on or helping to set your truck on fire when thinngs didn't work out right.