So my truck has been pulling to the left since before I got new tires. Both of my front tires were cupped on the inboard side - the right more severe than the left. I was told this could be caused by lack of rotating the tires (guilty). So last week I got four new Firestone Destination LE's and the truck pulls even harder to the left. When going down the interstate, if I am in the right lane and let go of the wheel I am in the left lane in 7 seconds.

According to my understand of toe (see photo of my handwriting below), they made the alignment come into spec by changing the toe to the left, which would make it drift left even more than before. Does this mean something else on my truck is messed up? Here is a list of the suspension work that was done before I bought the truck at 120,000 miles.

85,000 right front upper ball joint replaced
92,000 front stabilizer links replaced
93,000 right front wheel bearing replaced
102,000 both front lower ball joints replaced
145,000 current mileage - new tires & alignment

 

ya i would bring it back for another alignment and tell them its not close to going straight

 

yeah like said above, take it back to the place that aligned it and have them realign it, same thing happened to me and the place fixed it for me the next day

 

I brought the truck back to Firestone and they put it on the alignment rack again - same results. They took it for a test drive and said it was pulling to the left especially under braking. They told me the left front caliper was probably stuck and suggested a $650 brake job (front rotors, pads, calipers). I said no thanks and changed out the left front caliper myself for $38. It didn't make a difference.

So I jacked the truck up again after the caliper swap and spun the front two wheels and noticed that the right wheel spins freely while the left wheel does not. It is spinning the axle and therefore the opposite axle. Is the wheel supposed to disengage from the axle when the 4x4 is not engaged? It seems like this might explain why it pulls, brakes, and bump-steers to the left. I'm not familiar with 4x4 systems so any insight is appreciated.

 

It could also be the left rear brake dragging.

 

We have live axles, so everything moves even if the 4x4 is not engaged.

I agree with the poster above me. Check the rear brakes as well.

 

Would a dragging rear drum explain left bump-steer? I have drums in the rear so I wouldn't think this would affect the bump-steer as much.

I don't understand this. Why does the right wheel spin freely as if it isn't attached to the axle at all?

Firestone also told me that there was a deep groove in the front left rotor and that the rotor was probably warped. I checked and there are zero grooves and the rotor runout is 0.0025" - under the 0.003" spec. So I don't know if they were just trying to get $600+ out of me or what...

 

Pulling and bump steer are two different things.
Make up your mind which problem you're trying to fix first.

 

I know they are two different things. I'm just assuming the cause of each condition may be related (if not the same cause) since they both affect the vehicle dynamics in the same direction (left).

I'm still not sure that the left wheel should be rigidly attached to the axle when 4x4 is not engaged. Is it? If it is not, then bump steer left and drifting left would make sense, since in bump-steer once the wheel is airborn the drag from the driveline will immediately slow down the rotational velocity of the left wheel. Once that left wheel hits the ground again, the slower velocity would make the vehicle bump left. Wouldn't the same thing hold true for drift? If the friction of the driveline is slowing down the left wheel, that would make the truck drift left. Or no?

 

HANG ON A MIN.
Your truck is a 99 ranger right?
the 98-99-and some 2000 are like this
if so your axle should not turn unless engaged in 4x4 there is 2 lines going to each front wheel 1 line is the wires for your abs and the other is the vacuum line that engages the 4x4 vacuum hub. if your turning the left front tire and the axle turns your 4x4 vacuum hub on that side is sticking. Its on the outside of the wheel bearing when u take the tire off. It can just be pulled off there is only plastic clips that hold it on, very easy to get off. This is the peace that need to be replaced. The peace at the top of this piture is what it looks like.

Also you have your aliment. paper pic up and I see that the caster from left to right is 1 degree that not good they should be the same measurement on both sides also your camber is off from side to side these also should be the same these are the specs for 99 ranger
Front
Camber Range
-1.2° _ 0.2°
Tolerance
-0.7° _ 0.7°

Caster Range
3.2° _ 5.2°
Tolerance
-1.4° _ 0.0°

Toe Range
-0.07° _ 0.19°
Tolerance
-0.13° _ 0.37°
If you go back to that shop and tell them to do there job an aliment is more than just toe they need to do caster and camber before toe these angle reflect on your toe and need to be done first
If you fix the 4x4 vacuum hub and get the aliment the way it should be
I would almost guaranty it will not pull any more

 

Awesome! Thanks for the info, Oranger! I'm gonna be outta the country for a few weeks but I'll do some research and attempt the repair when I return and post my results. Thanks again.