What's up guys? I'm new on this forum - I've got a problem with a truck that i'm working on. It's a 01' ford PSD 7.3L diesel turbo 4x4.

The customer complaint was loss of power steering assist at idle and during parking lot manuevers. My shop does not have a power steering pressure gauge, so I was force to make an educated guess on what the problem was... The tension on the belt was good, the fluid was not aerated, and if I revved the engine - the extra rpm would raise the pressure enough that the wheel could move just fine. SOOOO... I diagnosed a defective power steering pump. I replace the pump with a dealer motorcraft pump and the problem changed to: Having powersteering assist at all times except WHEN THE BRAKE PEDAL IS APPLIED during parking lot manuevers and at idle. I then replaced the hydroboost unit, the steering gear, and all of the lines in the hydroboost system b/c they are multi-layered and in theory one of them could be collapsing internally under the extreme pressures.

This post is getting a bit lengthy so I will summarize what i'm after:

Has anyone else ever encountered having power steering assist (nice and smooth) at all times BUT when you put your foot on the brake at idle or going very slow??? The steering wheel is nice and easy to move - then you put your foot on the brake and it is damn near impossible to move the steering wheel more than an inch or two!

I have consulted every technician that I know, and have even called the ACDELCO tech helpline (~$5/minute)... all to no avail.

Any experience or ideas would be much appreciated. Thanks

 

I asked the same question when I first got my truck. Mine is an '01 4x4, also. It steers very hard when applying the brake pedal when stopped. When releasing the pedal slightly, it steers fine. Others have said they experienced the same problem. Seems to be an inherent design flaw. I have overcome the problem (sort of), by not pushing the brake so hard when going slow or stopped. Sounds like the new pump probably cured the low pressure problem, but the other is a matter of technique. Did the owner say anything about the hard steering, with the brakes applied, that had gotten worse lately?

 

I believe, I have read that the Two share pumps, Power Steering and Master cylinder.

 

Thanks for the reply mueckster. The customer complaint was simply "hard steering at times". So, what you are saying is that all of them are like this? Damn thats pretty sad... The guy I talked to on the tech help hotline told me that it was a poor design and that the ps pump pressure was barely enough to begin with.

 

I have an O1 PSD 4x4 and I too have experianced this very same problem when turning tight radius at very slow,(e.g. parking lots), or at a stop. I haven't experianced the same problem so much when applying the brake and I would tend to agree with the previous reply that this may be more of brake applying technique then an actual part failure. I would have to say if others are experiancing this that it may in fact be just a design flaw but I'm sure the guy with the truck may not appreciate that response. Good luck to you.

 

Like 02PSD4ME indicated, the power steering and power brake systems share pumps. When both are used at the same time, these systems do not work well. Call it an inherent design flaw, but if the pump is not working correctly, then the problem would be more severe.

 

I have seen where someone enlarged the hole in the fitting on the p/s pump to increase flow to the high pressure hose. I don't know if this would help any. You could shim the relief valve spring or stretch it out to increase pressure, but you would need to check the pressure first. I don't know the pressure limits for the system, so I haven't tried this.

 

Here is an SSM from Ford about steering effort on Super Duties:

17469 1999-2004 SUPER DUTY F-SERIES/EXCURSION - HIGH STEERING EFFORT
SOME 1999-2004 SUPER DUTY F-SERIES AND 2000-2004 EXCURSION VEHICLES MAY EXHIBIT INCREASED STEERING EFFORTS AT VERY LOW SPEEDS OR WHEN STOPPED WITH THE BRAKES APPLIED. CUSTOMERS MAY PERCEIVE THIS AS HIGH STEERING EFFORT. PLEASE REFER TO WORKSHOP MANUAL SECTION 211-00 FOR STEERING WHEEL TURNING RESISTANCE SPECIFICATIONS. INCREASED STEERING EFFORT AT LOW SPEED OR WHILE STOPPED IS A NORMAL CONDITION WITH HYDROBOOST OR VACUUM OPERATED BRAKES, THEREFORE NO SERVICE ACTION SHOULD BE TAKEN.