Wandering
 

I have a "wandering" problem with my 29 RPU. When cruising along it tends to wander slightly to one side and after correcting, it wanders off to the other side, so I am more or less permanently correcting it. The problem is not serious, just annoying especially on longer trips. I have established that there is no play at all in the 7-tooth steering box (checked in the vice with a dial guage) so the play must be either in the king pins, drag link balls or tie rod.

My question: What is the easiest way to diagnose the cause of the problem without dismantling the whole front end? I have had the wheel alignment checked by a professional who says the alignment and toe-in is OK. So what do I check next? Hope someone can help with this.
Mac

Re: Wandering
 

Inflate your tires to 50 psi and try it.
The other thing you can try is to put a friends tires and wheels on the rear and try it. Easy to do.

Re: Wandering
 

Mac-
Check your toe-in. Shoot for 1/16" +/-1/32" (Service Bulletins page 282).

Check also for king pin bushing wear. With tire/wheel off the ground (jack under axle) push in and out on the top and bottom of the wheel from the side to see how much wear there is.

Hope this helps.

:cool:

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Re: Wandering
 

If alignment and toe in is OK, then wandering from side to side would almost certainly be a sign of play in the steering linkages somewhere. (Note: Most alignment shops don't have a clue how to check the alignment on a model A, and modern computerized laser equipment doesn't have the settings entered to be able to align)

First, follow the guidance of Jim (Posting 3 above) to check toe-in and to look for play in the king pins and linkages.

The 7-tooth box does not have an adjustment for sector and worm mesh, and the bushings are subject to wear. With the front wheels raised off the ground, pull up and push down on the steering wheel to see if there is ANY up and down play in the steering shaft. Any up and down movement would allow your vehicle to wander, and is an indication of the bearings not being shimmed correctly.

I know you said you checked steering with a dial indicator.. not sure what you checked or under what conditions, as the only adjustment on the 7 tooth box is sector end play. You indicated that you checked in a vise... did you recently rebuild your steering box ?

Re: Wandering
 

While the answers above are all valid, the first place I generally go is to look at the front spring hangers (shackles) to see their position. When the spring has the correct arc, the hangers are more horizontal. The more the spring is worn, the more vertical the hangers will be between the perch and the spring eyes.

Next is to look at the front radius rod ball and socket to see how loose they are. If you can move it in any direction, it is too loose. Items like incorrect toe-in adjustment is what causes the axle to move laterally when the front spring or the radius rod is worn out of specs. This is why the vehicle wanders.

Re: Wandering
 

If something is stopping the self centering, I'd guess something is stiff.

It's sticking in one direction, then the other.

Assuming the caster is correct.
Easy enough to check if everything is moving freely.

Re: Wandering
 

Drop the front end and check everything out. Not that big a job.

To me everything mentioned above is good advice but their all saying the same thing when you put the posts together. “It could be any of a number of things”.

Front end and brakes. They need to be right.

Enjoy.

Re: Wandering
 

I wrote a pdf format in the search above on my wandering issues. I chased this for several years. After replacing a lot of front end stuff and out of luck I figured out what it was. For me it was the spring perch nuts. The drivers side took two and a half turns to tighten and the passenger side took 3/4 of a turn. Once I "snugged em up"the car steers quite well.

Re: Wandering
 

Ck tire pressures also.
Paul in CT

Re: Wandering
 

Thanks Guys,
Some really useful tips there. I will explore your ideas over the next few weeks and report on progress. I checked the play in the steering box by clamping the steering column in the vice, then clamping the steering wheel so it could not move, then measuring the movement in the pitman arm. The dial guage found only about 0.5 mm movement in the arm.
Mac

Re: Wandering
 

Besides tire pressure as I mentioned above, how OLD are the tires themselves??
Paul in CT

Re: Wandering
 

If the steering box is adjusted too tight it will want to go off centre.

Re: Wandering
 

Thanks again everyone for your helpful answers.
Thinking that tyres might be the problem, I swapped the front two tyres with two spares and pumped up all the tyres to 35psi. Result? Wandering problem gone!

Previously, when I checked the tyre pressures I found that three were only at 20psi and one was 33 psi, so that seems the most likely cause. However as I also swapped the two front tyres, I guess that could also have been a possible cause. Anyway, I am very pleased to have solved the problem without big expense.

Re: Wandering
 

Thank you for posting what you found as the solution.

:)

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Re: Wandering
 

The caster on the model A vehicles was fixed from the factory but is can change with heavy use and lots of bumpy roads over the years. Accidents can bend the axle and as was mentioned, the radius rod ball and socket can be worn to a frazzle. Caster and proper toe in are what keep cars from wandering around too much. Axles can get bent bad enough that caster and camber will both be off. The radius rod or axle can be adjusted to affect the caster.