Short Pitman Arm Problems

B

Bruce A

New member
I purchased a new short pitman from a reputable parts vendor after installing the steering was noticably easier but I did notice a reduced turning radius. The car steered great but wandered all over the road havind little play in the steering wheel before installation I now had 3-4" of play. The box clearance was right on at center of wheel but when the wheels were straight ahead there was left to right play. It appears that a longer drag link would be required to bring the wheel back to center and eliminate play. I did reinstall the original pitman arm and all is back to normal. Does any one have further input or ideas wih this problem ( besides leave it as Henry built).
 
Perhaps it seemed tight on the steering sector, but was not really quite tight enough? Any play there would add to loose play in the steering.
 
Bruce A said:
I purchased a new short pitman from a reputable parts vendor after installing the steering was noticably easier but I did notice a reduced turning radius. The car steered great but wandered all over the road havind little play in the steering wheel before installation I now had 3-4" of play. The box clearance was right on at center of wheel but when the wheels were straight ahead there was left to right play. It appears that a longer drag link would be required to bring the wheel back to center and eliminate play. I did reinstall the original pitman arm and all is back to normal. Does any one have further input or ideas wih this problem ( besides leave it as Henry built).
Click to expand...

1) The shortened arm is 80% of the original, or looking the other way, the original is 25% longer than the new arm. So, your reported "new" play of 3-4" would correspond to and old play of 2.4-3.6" If your original play was less than this, you did not have the new arm fitted properly to the box shaft.

2) The slight change in geometry from the shorter pitman arm will move the wheel center slightly. The position of the steering arm on the left front spindle also plays a part in determining steering wheel center. Cold bending of either the forged steering arm or the new forged pitman could safely provide a minor correction. Most people lacking the skill and equipment to make those corrections, often done on large trucks, would elect to replace the fixed drag link with an adjustable one.
 
Do you have a 2 tooth or 7 tooth box?I am asking because I have heard stories of reduced turning radius,But on all the ones I have put on and have looked at the steering hit the stops before and after.I have never seen or installed one on a 7 tooth so I wonder if that makes a difference.I have not been able to find anybody that can show me their spindles no longer hit the stops after.It does seem to me that it does amplify any problems in the steering,but that could just be because after working on things we tend to look for things closer.I don't care where the wheel is positioned,every one I own is in a different spot.
 
I agree with MCHinson. Seems to me the problem has to be loose fit where the arm attaches to box shaft. There are not many other things that changed! Maybe the starting snugness is sufficiently different to trick you into thinking it's tight when it's not. The tiniest play at that connection has a BIG effect.

Maybe you could detect the problem by close observation of the connection under a bright light while someone wiggles the steering wheel back and forth. A better test I have found is to firmly grip the connection with the flat of your palm pressed against the end while the wheel is waggled; you can feel if the inner shaft is moving while the arm is not.

Don't worry about the turning radius change; that is fully expected.

However, something you might want to look into is what stops the travel at the two extremes. Notice how it works with the original; the steering box housing should not take the hit. If it does with the new arm, it might be wise to build up the stops, or, at least, remember to be really gentle at the steering wheel limits lest you bust the box.

Steve
 
Bruce A said:
I purchased a new short pitman from a reputable parts vendor after installing the steering was noticably easier but I did notice a reduced turning radius. The car steered great but wandered all over the road havind little play in the steering wheel before installation I now had 3-4" of play. The box clearance was right on at center of wheel but when the wheels were straight ahead there was left to right play. It appears that a longer drag link would be required to bring the wheel back to center and eliminate play. I did reinstall the original pitman arm and all is back to normal. Does any one have further input or ideas wih this problem ( besides leave it as Henry built).
Click to expand...
Bruce;
I had the same problem and I didn't like the handling. I reinstalled the original pitman arm...a little harder to steer but no more wandering . Old Henry had it right...Bob F
 
I've seen adjustable drag links for sale, but, can't remember where.. It seems one would be needed to re-center the steering box.. Once a 2 tooth box[ don't about a 7 tooth] is off-center the play increases quite a bit, its just the way its designed..
 
Bruce;

I think that your Pitman arm is loose. I have a short Pitman arm and really like it. However, when I installed it I tightened it up with a 1/2" ratchet as much as I could and thought that it was tight. I then noticed that I had extra play in my steering and a slight vibration or shimmy in the 43 -47 mph range. A friend indicated to me that I might still have a loose Pitman arm causing the shimmy. I told him that the Pitman arm was as tight on the sector shaft as I could get it. However I removed the cotter pin and hit it with an impact gun and got about another 1/2 turn on the nut.

Bottom line: Play is back to almost nothing in the steering and the shimmy is gone.

Check your Pitman arm to Sector shaft tightness.
 
I found it helpful to have an adjustable drag link to "fine tune" the steering. Makes it easier to keep the steering gear on tdc and the wheels going perfectly straight down the road
 
Check out How to Restore your Model A volume 8 page 14-15 by Wiley Higgins.

This would maybe solve your problem ?
 
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