Steering wobbe

[Mad Mac]

I am trying to diagnose the cause of a slight wobble in the steering of my 1929 RPU. This is not the dreaded “death wobble” but more a tendency to wander at cruising speed. There is no play at all in the 7-tooth steering box and pitman arm (checked on the bench with a dial guage) and the steering column is bolted tightly to the frame. Therefore I assume the problem lies “downstream” of the pitman arm, probably in the drag link and/or tie rod connections. I will investigate them shortly, but in the meantime I want to eliminate other possible causes that could be cheaper and easier to fix.

Just recently I did two things that seemed to worsen it: I pumped both front tyres up to 35psi and repacked the bearings in the LHS wheel. I tightened the wheel nut as per recommendations in this forum, so am hoping it is tight enough. I would be grateful for any further suggestions

 

[Charlie Stephens]

What were the recommendations of this forum to tighten the wheel nut?

Charlie Stephens

 

[nomadpsd]

What is the toe-in set at? Incorrect Toe (especially toe-out) can cause wandering.

 

[1931 flamingo]

Ck toe-in. How old are the tires??
Why only repack one side wheel bearing??
Paul in CT

 

[daren007]

Alignment.

 

[Purdy Swoft]

I also think that toe in could be the problem . check and set the toe in at 1/16 .

 

[Patrick L.]

If everything is tight and wheels are straight/true I agree with toe-in.


Worried about the wheel bearing adjustment. Easy. Tighten nut while spinning wheel/drum just enough to make sure it just snug, back nut off to next or 2nd castle making sure wheel still spins freely. Install cotter.

 

[Tacoma Bob]

In my case after changing out everything over the course of several years it was the spring perch nuts. Driver side was loose by 2.5 turns. Passenger side 3/4 of a turn. Snugged em down very tightly and and no more wobble.

 

[katy]

In my case after changing out everything over the course of several years it was the spring perch nuts. Driver side was loose by 2.5 turns. Passenger side 3/4 of a turn. Snugged em down very tightly and and no more wobble.

I hope that you verified that you have the proper nuts on there, the ones with the taper of the end that fits into the radius rod. And don't forget the cotter pins.

 

[Jim Brierley]

Often the cause of wobble is looseness in the drag link ends. Check that and I recommend 1/8" toe in. Wheel bearings should be tightened very snug, rotate wheel a few times, then back off nut and re-tighten just enough to take out all the free-play. Check both wheels. Tie rod ends should be snug too. Wandering can be caused by castor and/or camber being off a little.

 

[Mad Mac]

If everything is tight and wheels are straight/true I agree with toe-in.


Worried about the wheel bearing adjustment. Easy. Tighten nut while spinning wheel/drum just enough to make sure it just snug, back nut off to next or 2nd castle making sure wheel still spins freely. Install cotter.

Yeah, thats what I did

 

[Tacoma Bob]

Katy....you betcha! My initial fear is that the taper had wallowed but so far so good. I went through hell until I figured it out. I replaced everything imaginable. One of out club tech guys asked me if there was rust outside of the boss's. Prior to figuring things out there was indeed rust where there had not been prior.

 

[Mulletwagon]

Jack up the front end under the axle and try to rock the wheels both 3-9, 6-12, and straight up and down. Any loose joints or king pin slop will be obvious. Also rotate the wheels to check for run out or other signs of a warped/bent rim. Please share the fix when you figure it out.

 

[Mad Mac]

What were the recommendations of this forum to tighten the wheel nut?

Charlie Stephens

Hi Charlie,
To tell you the truth, the recommendations were a little confused and contradictory, but the gist of it was that the nut should be tightened until the wheel starts to bind and then back off a quarter turn or to the nearest castellation hole for the split pin. Not too tight and not too loose, just like Goldilocks.

 

[Mad Mac]

If everything is tight and wheels are straight/true I agree with toe-in.

I had the toe-in checked at the local wheel alignment shop and they say it is good. However I'm not sure how much they know about Model A Fords.

 

[Patrick L.]

I had the toe-in checked at the local wheel alignment shop and they say it is good. However I'm not sure how much they know about Model A Fords.

Your statement about wheel bearings is about right. 1/4 turn back off may be a bit much. Not to tight and not too loose is correct


Toe-in is pretty much toe-in. Its pretty much a fits all. All cars need toe-in and the amount is usually 1/32- 1/8". Those numbers also work for an 'A', I prefer 1/23-1/16".