Hi there. Yes it is total loss of steering for 3-5 seconds not loss of power steering and the truck goes where it wants. It finally happened to the mechanic today and scared the crap out of him. He said the ABS sensor and the speed sensor etc. are the problem..so we will see.
Thanks

 

Just popped back on here to give you guys an update on my suburban that had the same problem. I have driven it every day now since changing the PS pump and put just a little over 700 miles on it so far and have not had one issue. I am 99% sure this solved the problem...it would usually do it to me 2 or 3 times a week and I would be all over the road like some kind of drunk!

 

I hate to say it but I don't think its ABS at all, at least in my case. When I first removed the wheel bearing from my wife's truck I accidently yanked the ABS sensor wire out of its connector. It was a week or so before I got the new bearing installed and the truck still had the problem while the ABS was disabled. The new bearing came with a new ABS sensor and the ABS is working again. Unfortunately the problem occurred in both cases. I think the 4wd. is intermittently engaging on one front wheel (drivers side in my case) due to something between the u-joint and the 4x4 locking hub. IMHO we have eliminated the 4x4 locking hub, wheel hub and ABS from the equation. I do want to add that I’m not convinced that the PS system should be eliminated as a culprit but based on EXv10’s experience I am leaning that direction. Fortunately between the wheel bearing and the locking hub replacement my wife’s truck only tries to crash itself every couple of weeks. Unfortunately the duration between occurrences makes the problem hard to catch. I am going to mount a small video camera pointed at the u-joint and try to confirm my theory. I have one of those cheapo X10 cameras that will do the trick. I may have to wait until the problem starts to occur more often to get a realistic shot at it.

 

Well,
I was going to put a new ps pump on today but decided to talk to the retired Ford tech again. As you all remember from a past post he told me to replace the vacuum pump. When I went over today, he told me that I was to replace the vacuum relay not the pump. I guess that I don't hear as well as I did.
This relay is suppose to turn on and off the auto 4 wheel drive hubs. He took my truck and did a vacuum test on the relay. The relay leaked a small amount of vacuum on the side that goes to the hubs. There should only be vacuum when the switch is in the 4wd position. He thought the hubs where turning on and off sometimes on the driver side sometimes the other. He replaced the relay for me ( it only cost $70.00 which was cheaper then the ps pump) I picked up my Excursion and it had no hint of pull or jerking. I will keep you all posted.

 

Thanks for getting back! I think the spool valve in the PS box actually does it but the pump causes it. It needs the full pressure for everything to work

 

I hope the vac relay does the trick. I pulled a fuse from the fuse box in the engine compartment to disable the 4x4 system early on with no success. The fuse is still sitting in the center console. I don't know much about the vacuum system but I would guess that my vac relay is disabled without the fuse. I suppose there could be some mechanical problem causing the vac relay to partially engage but my truck experienced the problem without the locking hub installed. Assuming that the vac relay does not solve anything I propose that we start a list of what the problem is not. Based on our multiple experiences we may be able to focus in on a culprit and avoid repeating what didn’t work for others. Please feel free to copy and modify the following list.



Did not help.
1. Disabled 4x4 system by removing fuse in the engine compartment.
2. Removed locking hub.
3. Replaced wheel bearing. (This + #5 helped some)
4. Replaced ABS sensor.
5. Replaced locking hub. (This + #3 helped some)


Possible solutions.
1. Vacuum relay.
2. PS Pump.

 

First, My truck usually was the worst when it was cold. This morning it was 40 degrees and no hint of problems. I was thinking about this last night. Would someone manually lock the front hubs and then drive your truck and see if the wheel stops jerking back and forth. With the hubs manually locked vacuum should not have any issue, right? If the problem comes back for me, I'm changing the ps pump.

 

I would do that test but the right binds when the wheel is turned to lock so I want to grease the hub assembly first. I doubt if the joint is bad because it only undergoes a third of the load (3 joints) and this is when you rarely use 4WD. Let us know about the PS pump if you change it.

 

Hi there. Wanted to check in. It was the right wheel sensor. There is a bulletin talking about the sensor but it stated that the brakes would be the only thing affected. Well surprise..when there are faulty signals in the system steering can be affected as well and in my opinion possibly other things. Also good to note is that just because the ABS light is on does not mean the system is disengaged it can mean the system has a faulty signal. See the bulletin on this and add our steering problem to it. It has not happened in a week of serious driving.

 

This only make sense if the the steering wheel jerking happens when brakes are applied.

 

A quick way to rule out a PS pump would be to do a pressure test.

 

My ex won't turn the wheels back and forth at all when it is stopped and there is a sshhh noise (not really a whine) when I turn either way on the road. (It's not bad on the road.) Do I still need to test the pump pressure?

 

I know other people have said the same thing about not being able to turn the wheel when on the brakes, I can without a problem. The sshhh sound sounds like the pressure is maybe being bypassed in the pump or steering box, so a pressure test would tell you if the pump is producing pressure or not ( I'm not sure what the pressure should be but can't be that hard to find out)

 

No, It;s with the brakes off. I realize it is harder to turn when the brakes are on because the wheels have to move a bit due to the geometry of the front end. It won't turn at all.

 

Well then I would say that you are losing pressure somewhere either a pump or a stuck open relief valve in PS pump or maybe a worn rotary valve in steering box. I think the best thing to do is find a shop with a Power Steering Analyzer and have them check your system this would save you from throwing parts at it and maybe worth the $75-$100 bucks. It's what I would have to do because I don't have the equipment and from reading the service information on page 6 in this post the pressure (750psi) and flow(1gal/min) need to be checked.