Front tire shoulder wear

[MIPS]

When I got my Eagle the *really* old Firestones had shoulder wear on the fronts. Ultimately I replaced them in 2020 because the outer shoulders were rapidly wearing down to the filaments and became a liability, especially on the drivers side. Replaced them with new Yokohama All-Season M+S that were slightly oversize and got the front end realigned.
Did a left-right tire rotation last year and a bunch more bushing, balljoint, bearing and front-end linkage replacement, plus alignments again when needed and I'm seeing the shoulders wearing down again. Verified the tires are properly inflated. Shop says the alignment is still perfect on the jig.
Started running into excessive road noise (rumbling and fluttering like a bearing was going) that I assumed was a problem in the front diff (new wheel bearings, remember?) and sent it in for inspection before I take it on the highway again. They said the front tires are feathered and to perform a 4-tire rotation, drive it for a while and see if the noise goes away.
The rotation is not a problem to do but why the weird shoulder wear only on the fronts with normal tire pressure and good alignment?

[Canoe]

> Shop says the alignment is still perfect on the jig.
What's the chance that they don't know the Eagle has adjustable caster & camber as well as toe-in?
And is there still movement somewhere in the suspension. Bearings?
Long shot: what's the torque pre-load on the half-shaft nut? Is that too low and somehow allowing movement?

It's been years since I've seen a left/right rotation. I've only done front/rear, keeping pairs on one side.

If the tires are somewhat oversize (in what way?), rather than a one-size-fits-all pressure, you may need to go to measuring temperature to determine if the tires are over/under inflated.

[AMC of Houston]

The term "good alignment" worries me.   I was a frame & alignment guy back in The Old Days.   I'm still set up at home to do alignments!   An alignment is only as good as (1) the alignment guy, and (2) the alignment rack "levelness"  and calibration.   Nowadays an alignment guy only knows what "the machine" tells him, and is clueless about theory.   Have a copy of your alignment receipt with the readings you could show us?   I'm curious where your guy left the settings.

[rmick]

http://amceaglesden.com/guide/Alignment_Specifications

[MIPS]

Checked with the shop and they agreed they must be missing something even though toe and camber is being checked. They can't blame much else because they are aware of how many new parts have gone into the front-end. They suggested I go to another shop nearby that is more specialized in alignments in case their computer is speccing the alignment to something wrong.

Shaft nut and bearings are still tight. That was all gone through a year and a half ago when the bearings were replaced. They still sound good as well.
I also did as per your suggestion and just did a front/back rotation instead and the noises absolutely went away from the front.

If the tires are somewhat oversize (in what way?), rather than a one-size-fits-all pressure, you may need to go to measuring temperature to determine if the tires are over/under inflated.

LT215/75R15.  Under normal driving and turning they are fine though in the winter when I put the mudflaps on the extra half inch on the wheel wells cause a bit of rubbing on hard turns.

[Canoe]

... toe and camber is being checked. ...

> the Eagle has adjustable caster & camber as well as toe-in

... Shaft nut and bearings are still tight. That was all gone through a year and a half ago when the bearings were replaced. They still sound good as well. ...

But was the nut torqued to spec (for the correct bearing preload), and a cotter pin put in place to secure it.

... I also did as per your suggestion and just did a front/back rotation instead and the noises absolutely went away from the front.

My understanding is that with (steel belt?) radials they should not have side-to-side nor 4-wheel rotations, only front-back. With 4x4, front-back is important for evening out tire wear so the tires' diameters remain very similar. As the front wears more due to steering, you need the front-back rotation to mix up that wear. Without that, with the front worn more to a smaller diameter, you're stressing/wearing the transfer-case more. In AWD cars and some 4x4, this will end up breaking. For reasons I haven't tried to wrap my head around, I've been told that worn/smaller-diameter front tires also stress the front diff. You get the same difference in diameter issue if you ruin one tire on a set that has some miles on them, and just replace the one tire, or one pair, instead of the whole set. Same issue having different tires that are the same nominal size of LT15/75R15 - you have to check that their actual diameter (not the nominal diameter calculated from the nominal size) is the same or nearly so. Good luck getting the actual diameter out of some manufacturers if you want/need to mix & match models.

...

If the tires are somewhat oversize (in what way?), rather than a one-size-fits-all pressure, you may need to go to measuring temperature to determine if the tires are over/under inflated.

LT215/75R15.  Under normal driving and turning they are fine though in the winter when I put the mudflaps on the extra half inch on the wheel wells cause a bit of rubbing on hard turns.

I'm talking about having a custom optimum inflation pressure for front tires and a potentially different custom optimum inflation pressure for rear tires. Measuring temperature across the width of each tire after driving while tires are hot, lets you know if you're getting even load/wear across the width of the tire. Lets you fine tune the pressure to match what your tires are actually doing. Google

My gut tells me there's more going on than alignment, rotation & pressure. I'm thinking there's gotta something that's still loose, or worn loose & only slips/pops out of correction position when driving. Bushing, ball joint, etc..

[MIPS]

The only bushing I got left is the spring perch bushings. As per another thread they are so shagged they move around and occasionally klunk on hard turns, but that shouldn't affect alignment like this, I don't think.

[MIPS]

Turns out the alignment recheck was free under warranty. Was sent to their specialty alignment shop across town where the boss man is an AMX guy, so he knows most of the AMC-ism's. Gave him your additional notes.

> the Eagle has adjustable caster & camber as well as toe-in

He's aware.

But was the nut torqued to spec (for the correct bearing preload), and a cotter pin put in place to secure it.

That I did not check but he did and found no issues. He was also the guy who rebuilt the bearings.

The SelectDrive is in 2wd most of the time as I don't trust it to stay together long with all the highway driving it does. Works great for the winter and dirt roads and the viscous coupling handles everything in between. I've just never bothered replacing just one tire unless something was really screwy. I know on newer fluff like Subaru's things can get nasty if you are running tires with different tire pressures or wear.

Anyways, here's the report card.



He did note a few issues in the passenger side but that was due to really old collision damage. At some point this got the passenger corner pulled back out enough that an alignment could still get done. It caused variance but he still had margins. The toe however did have issues.

[AMC of Houston]

If possible, shoot us a pic of the right lower control arm eccentric position.  It better be pulled all the way in - if not, someone is fudging on the alignment job.  Are the lower control arm bushings in good shape?

[MIPS]

Upper and lower bushings are no more than a year and a half old. Way back in 2019 I blew my wad on RockAuto and basically bought replacement rubber everything, so I got things like tie rod ends and factory shaped rad hoses before they went out of production. It was expensive but did the ride ever improve. 

You can see the eccentrics on both sides have been shifted recently.

[AMC of Houston]

Thanks for the pics.  Yeah; something isn't right since the eccentrics are pulled all the way in and you still have negative camber on the one side.

Have you looked up in there to see if the upper and (especially) lower bushings are (1) already worn out, and (2) make sure they were actually replaced by your shop?  I've seen a lot of work "flat-rated" over the years (work not done but charged for).

[MIPS]

Personal policy for me is that the old parts are returned with the car both to verify they were replaced and rebuild them if necessary. This paid off when my new brake drums turned out to be junk, twice. Way ahead of you. 

New control arm bushings, sway bar links and sway bar bushings are all MOOG. Strut rod bushings and upper balljoints are Mevotech and the lowers were Rareparts. I did the uppers and pretty much everything else myself but had the shop do the lowers because I didn't have spacers for pressing them out of the arm and while it was out they did the lower balljoints as well. I mean its possible I've already trashed them but I'm not that rough.

[AMC of Houston]

Good to know!   Any obvious clues that the inner fender on the right side was pushed in a bit once upon a time?

[Factory53]

Hi everyone,

I’m new to the Eagles Den forum and I’m curious if the image of the alignment specs in this thread is accurate for all Eagle Wagons?

The reason I ask is because I’ve got a 1984 Eagle Wagon, just had new tires put on it and I’ve called around to some shops in town to get an alignment done. I’ve called three shops and none of them will do it because they don’t have the “specs”.

I’m wondering if I showed them that image posted in this thread if they’d be able to do the alignment then.

Sorry to derail this topic but it sounds like there is a lot of alignment knowledge here.

Cheers.

[rmick]

The specs match my 1980 shop manual http://amceaglesden.com/guide/Alignment_Specifications