This is probably most applicable to diesel 7.3 guys.

I've gone through a few P/S pumps in the last year. The one on the truck when I got it didn't seem to exhibit any of the symptoms of stepping on the brake and losing steering, it was noisy when cold. The next two I had would not work the steering well at all with even a foot on the brake. Both were quite noisy, and the last one you could feel through the brake pedal.

So I got another one. These are all Cardone rebuilds. However, this time I want to modify something since i have one that works but is noisy in case I mess something up.

I drilled out the hole for the pressure hose fitting in the case from approximately 1/8". I think I went up to 7/32'nds of an inch but don't quote me on it. I'll have to go back and look.

From what I can tell, the Hydroboost is the limiting factory with the steering, since all the pressure had to go through the hydroboost first. So I think the hydroboost is effectively cutting off flow to the steering box. There are companies that modify hydroboost for higher flow. I don't know why the GM hydroboost setups don't cut off the steering with brake pressure.

However, that said, steering is MUCH better than any of the other replacmend pumps. It's almost a little "loose" feeling, but parking and slow speed manuvers are much better. I think a steering stabilizer will help with the loose feeling. This is all assuming that the output of the other pumps was adequate. I didn't try this pump before drilling the fitting.

I'll double check the drill size, but it seems that it's an easy way to make the steering work better.

 

So, you enlarged the hole on the outlet of the pump from 1/8 (4/32) to 7/32?

I think GM doesn't have a problem with hydroboost setup because they have a pump that provides enough pressure to operate both devices, even with a degraded pump, the pump has extra capacity designed into it. The Super Duty pump is just enough when new. Add oversized tires and the pump has to work harder to turn the tires. Add hydroboost onto that, pretty soon you are exceeding the pump capacity.

 

That's right, I bumped it up just over a 1/16th of an inch.

I thought so too, that the pump is just border line. Most of the limited information I've found seems to indicate that the hydroboost needs to be ported out to really solve this problem, not neccesarily throw more pump pressure at it.

Yet, solutions like the AGR pumps, which are modified saginaw style pumps seem to fix the problem as well. If this pump goes downhill on me again, I'm going to look into adapting a saginaw pump to the ford setup. I don't feel like paying the $200 something a place like AGR wants for it when the stock saginaw seems to work fine on GM trucks.

One thing I've noticed is I don't hear the pump go into bypass when the steering stops working while braking, like when you are at the stops on the steering. I'm pretty sure that is a function of the pump and not the gear box. If it did go into bypass then it would indicate the pressure requirements of the system have exceeded pump capacity.