Help Needed On Alignment Issues

[HawkRod]

My son's 73 Roadrunner (340, 727, A/C) has been aligned several times in the past few years, by a couple of different shops. It rides on 6 1/2" wide rally wheels with 235/60R15 radial tires.

In all cases, the ^%$#! thing eats tires. :angryfire: It seems that it has too much positive camber, since both front tires get severely worn on the outer edge. The inner part of the tread is like new.

The major suspension bushings/parts were replaced with Moog parts less than 12,000 miles ago (when it was restored), but I don't remember exactly when. I did not do this work, and I am not familiar with the 73 alignment method, although it seems there is an eccentric in the upper control arm to adjust camber?

Rather than just go get it aligned again, I want to try an fix this issue before it gets aligned again. Could the problem be the non-stock radial tires vs. stock alignment specs? Is something in the alignment cams prone to slipping?

Any help to point me in the right direction would be greatly appreciated!

Thanks in advance,

Hawk

 

[RustyRatRod]

It could be either too much positive camber, OR too much toe in. EIther will wear the outside edge excessively. Although you didn't say, I'll assume it has power steering. Power and manual steering require different caster settings. For good tire wear and nice handling on the street, line it up with the following specs.

Caster- 3-4* positive even on both sides.

Camber- -.3 - +.5* even on both sides.

Total Toe- .25*

All adjustments are in degrees. The cams in the upper control arms adjust both caster and camber.

 

[Hemi Rebel]

The eccentrics are for both caster and camber. There really isnt anything unusal about the alignment and the tires dont make a difference. I would make sure if you get one done again to have them check toe out on turns. There coud be an issue where the toe is in spec when the wheels are straight ahead, but go out of spec on turns. Its an extra step in the process and unless they are aware of an issue they probaly wont make that measurement. So be sure and tell them.

 

[440roadrunner]

What Rusty said. Camber with modern radials should be NEGATIVE, not POSITIVE. That's right, the opposite of original specs

Read this:

http://www.allpar.com/history/mopar/front-end-alignment.html

There is one "misunderstanding" in their "skosh chart"

The camber settings for "auto x" should read neg 2 to neg 3

and "max street" should be new .75 to neg 1

 

[RustyRatRod]

Alignment specs between radials and bias pliy tires ARE different and here's why. Radial tires keep the contact patch on the road longer than a bias ply through the sweep of camber change. So, in order to put that tread where it needs to be with a radial tire, the static at rest camber needs to be more negative than that of a bias ply. Nothing crazy, but I would consider .5* (1/2 a degree) about as far negative as I'd go.....unless you're road racing or heavily modified for street handling. Much more than .5* and you will run into wear on the inside edge. Of coarse we can solve that by adding more toe in, but this isn't an alignment class, so we'll save that for another time.

Power to manual steering also makes a difference. Manual steering feels better at low speed while trying to park for instance with less caster. Since you are picking the weight of the car up when you turn because caster is positive, you don't want a bunch of caster on a manual steering car. It'll be a beeotch to parallel park. With manual steering, you can have more. I usually tell people on old Mopars to try to get in as much as you can. They generally will not go as high as 4* although there are exceptions. Of course you can use offset upper control arm bushings, but I've never liked them. There's not much rubber between the bushing and the shell on the thin side.

 

[Hemi Rebel]

The point I'm trying to make here is if its in spec it shouldn't be killing the tires.Whats the factory spec? .5 positive. Not that drastic. Sure, its rolling on the outer edge a bit but it shouldnt wear out excessively fast because of it. How fast are they wearing out anyway? Did you get a print out at the last alignment?
If its killing them fast its toe. or a combination of toe and too far positive camber.Beyond factory. You should be able to see that if its too far. Does the wheel look like its sitting out too far at the top? Does it look the opposite of this?
This isn't a joke either http://www.youtube.com/watch?v=LgIrDyUEBjY&feature=fvwrel

 

[440roadrunner]

I tend to agree with you there


Sir, that van belongs to me and that is a copyrighted photo !!! NOT!!!! LOL

But I DID post that photo on occasion, the only thing stupider than low riders and DONK

 

[Hemi Rebel]

What the hell is donk?

 

[RustyRatRod]

There are so many varaibles here, that's the problem. Is the alignment machine calibrated? Does the "tech" know what he's doing? How does he make readings and adjustments? With the rack in the air? Or with the legs kicked down and the rack sitting level on the floor like it's supposed to be? Does he make his caster turn holding the tire like a dumbass, or does he do it with the steering wheel like he's supposed to? All of these things mentioned can have a DRASTIC effect on the outcome, yet, I have seen people I THOUGHT knew better make each and every mistake I outlined. This is something that will never be solved in an online forum.

 

[68 Sport Satellite]

Hey, you originally said the moog components were installed 12,000 miles ago. Check your idler arm and the pitman arm too while you're at it. Although your tires are getting eaten on the outside and a worn idler arm usually eats the inner tread. The reason I mention this is because both myself and a buddy installed Moog components and they lasted less than 2000 miles before needing replacing. It doesn't make sense, but it is what it is. This time we both installed idler arms from Firm Feel. Time will tell....

 

[440roadrunner]

What the hell is donk?

The stupidity HemiRebel posted is known as "extreme camber" or just "cambered"

http://www.youtube.com/watch?v=pt44izC49Vs

http://www.youtube.com/watch?v=_r6ltUgtFWI&feature=related

http://www.youtube.com/watch?v=LgIrDyUEBjY&feature=related



DONK:

 

[Hemi Rebel]

Im sorry i asked

 

[RustyRatRod]

I remember years ago.....back in the 80s the fad was gettin um as low to the ground as you could. Lowest profile tires possible.....they would even take coil springs completely OUT and let the car ride on the jounce bumpers. Now, it's goin the other way. Biggest wheel you can fit, highest you cen get it. I think all that stuff comes from overpaid basketball players with nothin better to do.

 

[67 coronet]

just to get back on topic,have you adjusted the ride hight in the front end after your alignments?this can change camber dramaticly.all great info above,but unless something is left loose or you have worn/bent parts a factory spec alignment will no were tires in the pattern you stated.i would do a full shake down of your front end.to check everything corectly put car on jack stands and then jack wheels to ride hight(under lower ball joints)and then check for looseness in steering and ball joints(grab tire and try to move in same direction as steering to check linkage and grab top and bottom of tire to check ball joints for movement)many shops dont do ball joint test corectly and miss loose ones.

 

[RustyRatRod]

Yup, all good points. Cause it's one of two thAngs. Either it AINT aligned when he says it is, OR something is moving after it's aligned. Either way, it's the alignment man's fault cause he's doin a piss poor alignment OR he's doin a piss poor inspection of parts.

 

[HawkRod]

Gents,

Thanks for the useful information - lots of good stuff here! :headbang: The suspension parts are all new(er), again within 12,000 miles, so I think it is less likely to be anything there.

Having said that, and since I have many times made assumptions that were bad, and those cost me time, money, curse words, etc., I'll check everything.

Here's my plan - I'd appreciate any feedback and suggested improvements:
1) I'll put the car up in the air as suggested by 67 Coronet and check suspension components for any issue that I can find. (I do know that the steering box has some slop in it, so I will check all of that extra carefully.)
2) Fix any issues that I find in step 1. Although if it is only the steering box, leave that alone for now (not sure why that would cause tire wear?). By the way, the car does have power steering.
3) Buy and install new tires
4) Take it to an alignment shop. I know one (where I have not taken it before) that has an 'ol timer who seems to know his stuff. Ask him to check the alignment and give me a printout of it BEFORE changing anything.
5) Based on the alignment results, and what was replaced in step 2 (if anything), evaluate any further issues with the front end.
6) Assuming a problem is found that is believed to have caused the issue, align again for radial tires with specs suggested by RustyRatRod

Let me know what you think!

Thanks again...

Hawk

 

[67 coronet]

Gents,

Thanks for the useful information - lots of good stuff here! :headbang: The suspension parts are all new(er), again within 12,000 miles, so I think it is less likely to be anything there.

Having said that, and since I have many times made assumptions that were bad, and those cost me time, money, curse words, etc., I'll check everything.

Here's my plan - I'd appreciate any feedback and suggested improvements:
1) I'll put the car up in the air as suggested by 67 Coronet and check suspension components for any issue that I can find. (I do know that the steering box has some slop in it, so I will check all of that extra carefully.)
2) Fix any issues that I find in step 1. Although if it is only the steering box, leave that alone for now (not sure why that would cause tire wear?). By the way, the car does have power steering.
3) Buy and install new tires
4) Take it to an alignment shop. I know one (where I have not taken it before) that has an 'ol timer who seems to know his stuff. Ask him to check the alignment and give me a printout of it BEFORE changing anything.
5) Based on the alignment results, and what was replaced in step 2 (if anything), evaluate any further issues with the front end.
6) Assuming a problem is found that is believed to have caused the issue, align again for radial tires with specs suggested by RustyRatRod

Let me know what you think!

Thanks again...

Hawk

sounds like you are on plan now.a before and after print out is a must!let us know how it comes out.

 

[HawkRod]

Update so far...and another question

Thanks for the help so far. We bought new front tires (but not yet installed) and checked all front suspension ball joints, tie rod ends, etc.

I'm no professional, but here are the results I got from checking the front end: All looks OK except for two areas where I have questions:
1) The upper control arm could be pried slightly off the center line of the axis of the shaft. This didn't "feel" or look bogus, it seemed like the rubber bushings were taking up the pressure and allowing some give. Hard to describe in words, but does this seem normal?
2) Play from front bearings was high and not right. There was a noticeable "wiggle" of the front wheels. We readjusted by tightening the bearing nut to 90 inch pounds while turning the rotor, turned back enough to line up cotter pin, and reattached the cotter pin. This took care of that problem. Could excessive play from the front bearings cause excessive wear on the outer edges of the front tires?

Any feedback on what you think would be appreciated!

Thanks,

Hawk

 

[YY1]

For the record, the brand new Moog idler arm I installed last year had a paper in the box that said "lubricate every 2000 miles".

2000!!! WTF, that's less miles than between oil changes, and it certainly explains why a previous poster had failure at that interval.

I think part of the problem is that the replacement part comes with a simple foam washer tha tis supposed to hold the grease in.
this surely can't be as good as a true grease boot.

- - - Updated - - -

loose bearings should wear inner tires eh?

In any event, that sure could cause crazy handling issues.

I always tighten them by feel- enough to get a little drag, then back off until it's 99% gone.

 

[HawkRod]

YY1, Thanks for the feedback.

No crazy handling issues, the bearings weren't all that loose. As I think about it, I seems to make sense that loose bearings would wear the inner tires - the tires would probably have a tendency to go toe out if anything.

We'll I'll soon have it at the alignment shop and perhaps the "experts" can find something...