Road Crown Alignment Problem

dodge
dakota

#1

My truck is a 2001 2 wheel drive Dodge Dakota with 67,000 miles. I have now had three closely spaced wheel alignments which always yield the same answer: if I am on the right side of the road crown, the truck pulls to the right. If I am on the left side of the road crown the truck pulls to the left. This is not subtle, the steering wheel is over about 45 degrees with some real force in it. On a flat road the truck’s wheel is dead straight with no sensation of pulling. The truck did not behave like this when new (I thought it was one the nicest alignments I have known).

The truck has had new tires, new gas shocks, numerous tire rotations, careful tire pressure measurement and always EXACTLY the same result. The ball joints have been checked repeatedly by shops and myself. The steering gear appears to have no slop in it. The vehicle height is only about 0.1 inches lower than specification. There is no shimmy or vibration. The only thing that seems to make any difference at all is the level of the fuel tank, but that might just be my imagination.

The problem is driving me crazy.


#2

There must remain a problem with the suspension system of some kind or the other. Broken or loose springs, bad tie rod ends, etc. I can’t imagine an alignment shop can’t figure this out. Are you using a speciality shop that only does alignments? Have you really loaded this truck to approaching it’s load limit? Drive over rough roads a lot? That would be a clue.


#3

Did you change the tire size? Also have you had an accident in this car requiring a body straightening? It is possible that you need a body shim for the subframe mounts. Your steering angles are off and the one thing a alignment cannot do is change the value of the subframe to frame distance. This happened to my brother inlaw on an infinity years ago. It took the dealer and the manufacturer 6 months to agree that the frame was out of spec and shim the subframe.


#4

George, the tie rod ends seem perfect, springs seem good as height is correct. It runs dead quiet so nothing is loose. And no, the truck has not been overloaded, but it has pulled a trailer, though the trailer was well within limits. I have not gone to a specialty shop. At least one other Dakota on the web with the same problem.

Euryale1, The replacement tires are just like the originals, the exact OEM Goodyears, and this problem existed with the original factory tires anyhow. I don’t think that the Dakota uses a subframe, it has a traditional full length chassis. No accidents.

Thanks to both of you for the comments.


#5

When you figure this out, please do post about it! I have the identical issue–though my truck is much older (1992).


#6

What was the caster spec? How “seasoned” have the mechanics been who worked on the truck?


#7

I never had this problem with my 95 Dakota, but my 1993 Caprice had a bad pull to the right on crowned roads. After two alignments and a front to back tire rotation had no effect, I switched the front tires from side to side and it tracked straight after that.

Ed


#8

I would guess that the caster is set more to the high side of spec. Caster tends to make the “self centering” force higher as more angle is dialed in. Check to see that the toe-in is set to a bit more on the high side, too. Crown naturally causes the car to lead left in the left lane and right in the right lane. More caster and less toe in would tend to make the truck more sensitive to crown. I hope this helps but this truck may be really sensitive to tire and alignment combinations.


#9

If you have the printouts for the alignments you might consider posting the specs. Some special attention might be paid to caster and possibly camber.


#10

Are you carrying any weight in the truck? If so, is the weight behind the rear wheels?


#11

No, the truck runs quite light most of the time. Below are some numbers from the first alignment at shop “A”, I had a some tire wear, after that job the tires have been wearing perfectly. I got a second alignment at shop “A” with a more thorough discussion, then I changed to a very careful shop “B”. I made it very clear to shop “B” that they should be looking for a problem (shop “B” does excellent work).

On the first alignment the mechanic said it was off spec. In the following two alignments both shops said it was close,

Front
Camber -0.3 0.3 -0.5
Caster 3.1 0.3 2.8
0.7 0.7


#12

How much road crown do you have, a lot or a little?


#13

I’m not sure if the above printout is the before or after data. One theory of mine is that the shops are not using data for my factory “wide” tire option. And thanks for the hints, Mustangman.


#14

I had the same problem when I first started driving. We took a trip through NC and my mother insisted that I drive. I kept veering to the right; the road crown was quite high. I got frustrated and she said to suck it up and learn how to deal with it.

As for both cars (yours and mine) veering off the road, I suspect that it is gravity. If you don’t have the problem any other time, that adds to the likelihood that you’ve just shown that stuff falls ‘down’.


#15

Did this start after the first alignment or did you get that first alignment because of this problem? Is the caster and camber set using concentric bolts like Chrysler products of the 60’s and 70’s used?


#16

Keith: I had the first alignment done due to both a tire wear problem and the road crown problem. The caster and camber seem to be set by slots in the control arms(?).


#17

OK, then it isn’t what I was thinking. Two things come to mind, some of the trucks of this era had issues for the upper ball joints, I don’t remember if there was a recall or just a TSB. The other issue is the drag link bushings. There are other names for this bar but it goes from the lower control arm just inboard of the ball joint to the frame at the front of the vehicle. I don’t know why the bushings would go out but they would be worth looking at.

What you are describing sounds like a severe change in the camber, which would be caused by either the ball joints or the control arm bushings. If it were the control arm bushings, I would really be surprised as they usually are good for 20 to 30 years, although they do check around the edges and that leads people to believe they are bad when they are not.

Here is something you can do, with the engine idling in park and the brake set, have someone turn the steering wheel about 1/8th turn back and forth, not real fast but not real slow either while you observe all the different components under there. Sometimes you can see a joint or component that is not moving smoothly or in sync with the rest of the components. For example, the idler arm may be moving up and down instead of just side to side, I’ve seen this in a lot of trucks. This would be missed in a regular static inspection.


#18

Hi Keith,
Good idea. I will try your experiment when Sandy is safely past us!


#19

There is indeed a ball joint recall out for this truck and I might add something about the inspection of ball joints and tie rod ends, both of which use ball studs in a socket.

Most inspections are done to determine if the ball stud is loose in the socket. However, it is quite possible and quite common for a ball joint or tie rod end to be worn and still remain tight. They can develop a flat spot on the ball end of the stud and this can cause a vehicle to move one way or the other depending on the slightest movement of the steering wheel.

Sometimes the only way of really knowing is to separate the tie rod end from the steering knuckle and manipulate the tie rod end ball stud by hand to determine if it has a flat spot. The steering knuckle (with tie rod disconnected) can be more easily turned by hand and often an oddly worn ball joint can be detected this way although not with 100% certainty. In some cases it might involve separation of the joint from the knuckle but that brings up the Catch 22 of replacing it since it’s apart.


#20

2 thoughts:

First both the cross caster and the cross camber are a little outside what I think is needed to assure good alignment - about half what the published values are.

Second, there must be something moving to get the pull to change directions. It might be something loose from the previous alignment (It doesn’t have to be loose much), or it could be something worn that is shifting. I like the ball joint idea - it would explain everything