[Striker66]

We have a 2004 Sienna and we have gone through 2 sets of new tires due to uneven wear (outer edge of tire wears out). We have taken this vehicle to have alignment done every year but same wear occurs. We even have taken this van to a mechanic who noticed the rubber boot on the steering rack was torn and told us that was the problem and wanted to charge us over $1600 for the job (I said no thanks by the way and did it myself for a fraction of the cost). Even after the replacement of the rack and pinion, the problem with the tire outer edge wear continues (yes, I had an alignment done after rack and pinion replacement). Any insight to what I need to replace/repair to have this problem fix is appreciated. Thanks so much

I have included a picture that I have downloaded from the internet to show how similar my tire looks

 

[Striker66]

did some research, it seems like the problem is pointing to worn out lower control arms and/or control joints?

 

[sharkinstx]

How many miles on it? It could be worn control arm bushings or worn ball joints, so you could have those checked by a reputable shop. It can also be caused by worn and sagging springs, and the van just settling.

McPherson strut suspensions like on the Sienna don't have the ability of camber adjustment - the tire wear you're seeing is from positive camber:

Camber angle - Wikipedia

en.wikipedia.org

You can ask a shop about installing cam bolts in place of one or both strut-to-knuckle bolts (depending on how much camber change you need), so that the camber can be adjusted. There are probably others out there, but the ones I'm familiar with are NAPA Fast-Cams. I had some installed by an alignment shop, on a Previa I once owned. They cured the tire wear problem that the first owner of the van wasn't able to get fixed.