Rear Alignment toe, fixing thrust angle, what can you do?

Here is a problem I don't know how to solve.... Comments welcome.

Rear axle alignment. ​

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No factory adjustments are available....

Loosen u-bolts and adjust axle while on rack?

 

@thefatkid
@Evenflow
@stairgod

Any comments? ideas?

 

Not much you can do. Honestly it is a Tacoma thing. Pull up other people's sheets that have been posted, you will see the same thing with differing numbers but relatively close.

Toe is only going to affect tire wear, no driveability issues.

 

Also, note your thrust angle. That is a result of it. If you are familiar with the term dog tracking that is what would cause the issue.

 

Seems like that would be the only way to recenter the rear axle.

 

@14 Tacoma Thanks for commenting. Yes, it was tire wear I was concerned with

Based on the above, I assumed a linear relationship and did the following math

1/16" = 0.0625
0.32 / 0.0625 = 5.12

5.12 x 7 feet = 35 feet.

So does that mean my rear tires are scrubbing almost 35 feet sideways for every mile?!


I'm getting an education over here now: http://www.knowyourparts.com/technical-articles/understanding-thrust-angle/

I never realized how important thrust angle was until now.

 

Yep, notice your total toe is good, that means your axle is shifted slightly. The right needs to move forward slightly and left back.

 

axle is straight but at a slight angle with the frame as measured by the machine.... likely its not at an angle.

 

Okay. Sounds good.

I could do this easily in my driveway. But since we're talking about such a slim margin I have no way to be precise.

I wonder if the guys at the alignment shop could do on an alignment rack?

Loosen u-bolts, unload suspension somehow while on the rack, reposition axle, load suspension.

Does that sound feasible?

 

I've had luck using a large rubber mallet with the u-bolts loose, vehicle still loaded.

 

Thanks a ton. I'll give that a shot!

 

I should say that I use a 7lb dead blow rubber mallet. Not a standard wooden handle guy. If you don't use a dead blow that hammer might bounce back and hit you.

 

I seem to recall my numbers showing the same and my truck always pulls to the right, sometimes worse than others. The spring centering pins won't allow for much movement but maybe all you need is a 1/16th of an inch.

 

I shimmed the rear leaf pack a couple weeks ago. I had a technician realign it after since my thrust angle had changed and the steering wheel was now off-center. I couldn't believe how off the passenger rear tire was/is so I need to put it back on the rack and attempt to reduce some of the positive toe that I have, we didn't have the time we needed when doing the alignment the other day.

I'll see how much, if any, improvement is had when I attempt to adjust the rear. It really bothers me knowing something isn't +/- perfect.

 

Always good to see a problem that can be solved with a BFH.

 

Truthfully, you'll be chasing this forever probably


First, you are not scrubbing your tires. Both tires point the same direction \ \

Your front tires properly aligned also point the same direction | |


So your rear tires want to steer you to the left, to keep that in check you slightly steer to the right. Both front and rear tires now track together. | |

The only thing you might notice is a slight off center to the steering wheel. Your truck body may appear to be slightly angled going down the road(dog tracking) \ , but your tires are tracking true.

To get tire wear you have to have a push of opposing direction tires / \ or \ / That is scrubbing the tires, or camber would have to be off which is nearly impossible on a solid axle rear end.

 

You have Dakars correct? I also have the exact same toe problem. Mine is positive 17 on the left and negative 16 on the right. I also have dakars....My truck wants to pull to the right I think due to a thrust angle of 16 or so. I tried loosing the bolts and using a ratchet strap to pull the axle back on the left and forward on the right but it only changed it a couple degrees.

 

Thanks a ton Clinton!

You crystalized it for me. I understand now. I really only care about tire wear. If an opportunity comes to loosen u bolts, I'll try, but not gonna make it the focus of one of my tasks.

Yes, Dakar. Yes slight right angle to steering wheel.

I pulled and reconfigured my leaf pack back in October. I've compared alignment sheets before and after, and my truck has always been possitive toe on left rear, and negative on right rear by equal amounts. However the values were slightly different, old sheet was quarter degree vs third now.

 

yup, you already guessed it buddy, loosen up those u-bolts and re tighten while on the rack but ultimately with leaf springs your ability to adjust is very limited. @nfs257 mentioned a shop in Temecula that would do true 4 wheel alignments on trucks but again your axle is going to sit on that pin no matter what. Even with heim'd links like I have you can only adjust in half turn increments of the heim.

 

Issue with this normally is that the center pin snaps and the axle shifts