Power steering Super sensitive

Tiny
JSHIELDS369
  • MEMBER
  • 1961 FORD FAIRLANE
  • 7.0L
  • V8
  • 2WD
  • AUTOMATIC
  • 100,000 MILES
Car is a1956 ford fairlane fitted with a 429. Has the original power steering system for that year but has a pump from a 72 ford car. The problem is that the steering is VERY sensitive at highway speeds and is dangerous to drive. Someone has put an adjustable restrictor in the system (not sure wheather it is in the pressure or the return side as the car is not in front of me at the time). Was wondering what I need to check first. Thanks in advance.
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Wednesday, February 17th, 2016 AT 10:25 AM

5 Replies

Tiny
JOHNNYT73
  • EXPERT
The only advice I have is to check the gearbox (if equipped on this car). There may be an adjuster on top of it to increase the tension. It is usually about a 16mm nut with a hex head screw in it. You break the nut loose use a hex key to turn it clockwise to increase the tension.
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Wednesday, February 17th, 2016 AT 10:40 AM
Tiny
CARADIODOC
  • EXPERT
What I'd look at first is how hard it is to turn the steering wheel when the car is not moving. If that has the normal resistance, and the steering effort only gets real easy at highway speeds, the next thing is to check the alignment. In particular, see if "caster" can be increased. Up through the mid '60s cars and light trucks usually had negative caster, meaning if you looked at the suspension from the side of the car, the upper ball joint was forward of the lower ball joint. That makes it real easy to turn the steering on even heavy trucks with no power steering.

By the mid '60s it was common to be driving faster, and negative caster allowed a lot of steering wander. Caster was increased to about three degrees positive to make the cars much more stable at higher speeds but that seriously increased the required steering effort. Power steering was added to overcome that high effort.

If the car still has negative caster, or very little positive caster, it will wander and require constant steering corrections, which is very tiring, and the steering effort will be too low. Another way of looking at higher steering effort is to call it increased "road feel".

Positive caster, which can be compared to the angle of a motorcycle front fork angled rearward at the top, causes the right corner of the car to be raised up when turning to the right. That is where the high steering effort comes from. That is also what makes the steering return to center by itself. Another clue that caster is too low is you have to help the steering wheel come back to center after turning a corner.
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Wednesday, February 17th, 2016 AT 10:44 AM
Tiny
CARADIODOC
  • EXPERT
Hi JOHNNYT73. Don't mess with that adjustment. That is not meant to increase steering resistance. That affects the amount of play or looseness between the gears. If it's too loose, you'll have excessive steering wander and the steering wheel can be turned a ways before the steering linkage responds. If it's too tight, the gears will bind when the gearbox is centered. You'll have to constantly hold the steering wheel centered. It will try to bounce off to one side all the time. That makes for a real miserable car to drive. There is only one correct setting for that adjustment.

It should be pointed out however that if someone previously loosened that adjustment, the free play in the steering wheel can be mistaken for light steering. I have never found a good way to set that adjustment other than to tighten it about 1/8 turn at a time with a test drive in between attempts. Over-tightened and binding can feel the same as loose and sloppy. Instructions in service manuals never work either. They give torque specs to set the adjustment, but in the times I've tried that, it never gave good results.
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Wednesday, February 17th, 2016 AT 10:53 AM
Tiny
JSHIELDS369
  • MEMBER
Thanks for the replies. I understand that the gearbox has been replaced as original equipment. It is not an integral power steering gear and I understand that the adjustment on the gearbox is not the source of the problem. I'll have to check with the owner of the alignment has been checked. I just wondered if the pump was making more pressure than the original components were designed to operate with ( hence the restrictor).
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Wednesday, February 17th, 2016 AT 11:04 AM
Tiny
KEN
  • ADMIN
It sounds like you are in the right ball park, I have seen this problem before but never had to fix it, some of the older cars just turn easy, if the pump is delivering higher pressure than normal then you will have this problem, just not sure what to do about it. I dont like the restrictor because it will cause the pump to fail. Might want to try a new pump maybe the pressure regulator inside is stuck or not working.
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Tuesday, February 23rd, 2016 AT 12:55 PM

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