irratic power steering boost?

J

j rick kirby

Guest
When going thru a continuous curve like a cloverleaf the effort required to turn the wheel seems to change making it difficult to be smooth and stay on the correct line.My suspension and rack is new.My pump is origional.Any ideas?
 
power steering

I am using Bilsteins so I have no ARC and my fluid is full.
 
Variable orifice?

The subject is no reflection on you personally :D I believe that these systems are variable assist through use of a variable orifice. Is it possible that this orifice is going bad? Symptoms as you describe could also be from air in the lines (so bleed it) or a bad rack. As the rack is new I would think it is one of the other two. Good luck.

Anthony
 
I would have to agree with the variable orifice valve. I am unaware of the method used to control ps pressure, but this sounds right. Look around for a place in the power steering system that might harbor the device.. check the lines, near the pump, ect. Also, who replaced the power steering rack? Perhaps they can provide more insight about where the orifice is located. Another idea.. if these pumps are belt driven, perhaps the belt is slipping. Check it for wear, fine cracks, tension, ect. and replace as necessary.
 
Check the book...

If you have any of the shop manuals, I'm sure it's in there with a desription of how to test it if I remember correctly. If you don't have a book let me know and I'll check when I get home.

Anthony
 
diagnostics help from C to C SC

Anthony,I don't have a manual so I would greatly appreciate you checking it out.
 
Same problem

I thought they were supposed to do it. My '91 did it and my '95 does it. It would be great to figure this out. Sorry I can't be any help. Brandon
 
Just a thought...(long winded)

It just occured to me that if your RPM/speed is changing well than yes, the effort required should change. That is the nature of variable power assist. If speed and RPM are constant then the effort should be constant. For example: When I find myself on a decreasing radius turn (off ramp) I will allow the car to slow as I come through the turn. The variable assist will respond by increasing the assist and it is possible that the required effort on my part decreases. On the other hand, in an increasing radius turn (on ramp) my speed will increase throughout the turn. The reponse of the assist system is to reduce the amount of assist and the required effort on my part may increase. Each of these system would feel more linear or perhaps even reversed when compared to a linear power assist or non-assisted system. I know I'm not telling you anything new but I wanted to be sure we are alll in the same understanding of the system and how it functions. As I said, I'll get some more specifics about the system and get them to you tonight (western time zone)

Anthony
 
You have mail...

The EVO (name for this sys.) actuator (variable orif.) is mounted right behind the ps pump. There is a test port for the operation of the EVO system and I bet the Ford stealership would be more than willing to blow the dust off of the diag. manual for this thing. I have scaned the corresponding pages that I have but I warn you, the info is limited! Just let me know (as I said in the e-mail) and I will get that stuff off to you.---The system is more complex than most people (myself included) give it credit for.

Let me know,
Anthony
 
Has anyone found a concrete answer and remedy to this problem? I'm having the same symptom myself. I would really like to address it if possible.
 
Every SC I have owned has done this to some degree or another. (I've owned 7), and I have never had the problem go away. I've replaced lines, racks, pumps, and fluid to no avail. Probably the only thing I haven't replaced is the EVO valve itself. Maybe I should.

I'd really like to find the solution. I find it is most annoying on a moderate constant radius turn at any speed over maybe 30mph or so.
 
I have owned 4 different t/birds & my cougar. Plus have driven numerous birds & cougars ( having owned an auto repair shop for 10 years). All of them have done this. No one at Ford or rebuilders of steering components could offer a solution.
Derek
 
Ditto here. Although the problem is worse whenever the fluid gets low. Do any of you have stiff steering on a cold morning just after startup? I do. Wonder if its related?
 
I would be willing to be the guinea pig and replace my EVO valve it it isn't a million bucks and everything else has been attempted. I'll be calling Ford tomorrow.
 
I wonder what would happen if you eliminated the evo alltogether, I mean ford built plenty of cars without it and they steer fine, I may just try it and see what happens.
Ron
 
fubar107 said:
I wonder what would happen if you eliminated the evo alltogether, I mean ford built plenty of cars without it and they steer fine, I may just try it and see what happens.
Ron

What would be involved in doing this? I kind of like that idea myself, since it doesn't seem like the speed sensitive set up works properly on anyones car now that they're 7-14 years old. Is a rack change involved or just the pump and lines?
 
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