Front end alignment questions

[67carry-all]

Hi all - just had the front end of my '67 Suburban rebuilt - ball joints, tie rod ends, pitman and idler arms, by a local shop. The mechanic has aligned the front end twice, but there's still a significant pull to the right when driving. The (original) steering box is a little loose and he thinks this might be contributing. I'm thinking it shouldn't matter regarding the pulling - if the alignment is on target, the truck shouldn't pull. Thoughts and feedback? Thanks!

[Bigdav160]

Tires? Do they have a balancer that can measure radial force variation?

If not just moving tires around in different positions can tell if the pull is tire related.

What are the alignment measurements?

[67carry-all]

Thanks for the reply. The tires are near the end of their life and look pretty even, but I did swap front to back and it did seem to help some. There is still some bit of pull. I'll drive some more and take a look at some of the other suspension parts, too. I didn't get the measurements the shop used; in hindsight, should have asked. Not familiar with radial force variation - is this measured with a spin balancer or ??

[INSIDIOUS '86]

Did they check rear thrust? Making sure the rear is 90* to the frame?
Also are your roads crowned in the middle with the yellow line the highest part and the sides lower?

Have any specs on hand what your front alignment numbers are?
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[Special-Ed]

rotate the tires... tires can cause a pull.

[67carry-all]

Unfortunately, no specs on hand - didn't get a printout or similar and at the time didn't think to ask. Until a month or so ago, the truck's alignment seemed basically fine (as in no pulling, no obvious uneven tire wear) until the suspension parts went south. I was assuming (never assume!) that replacing the parts, along with the alignment, would put the truck driving in a straight line. The front/rear tire rotation helped some, but there is still a definite pull, even on roads with no road crown. I'm thinking I should be looking for a change in something else with the suspension. I was surprised to find the lower rear shock bolts were loose, one very much so. Tightening these was obviously a good thing to do but made no change in the pull.

Other things to consider - I've noted the truck bounces a little unevenly (diagonally?) when going over bumps on the freeway. The shocks seem to pass a bounce test if I individually bounce each corner. Is this a shock problem or something else? At maybe 20-30 mph there is a barely perceptible side to side "wiggle" of the truck - I don't feel this in the steering; something in the rear suspension? How does one test or check for worn control arm and panhard rod bushings?

In summary, I plan on taking the truck back to the shop to check the alignment once more and would like to have as much info to help solve the alignment problem (and others, if the above are not contributing). So far I know to ask for the the specs he's using, asking if he did a 2 or 4 wheel alignment, check rear thrust/alignment. Any further thoughts/input with the additional symptoms above greatly appreciated - thanks for all the help.

[Lee H]

Brake dragging?
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[67carry-all]

Wish it were that simple and easy, but nope, no brake dragging.

[poorboy]

Was the wiggle felt from the rear prior to the tires being rotated from the front? You could have a separated tire that could cause the wiggle and also the harder pull while they where on the front. I would ask for the printout to see what your specs are. If you have a camber or caster lead to one side it can cause a pull. I generally set camber even and have a .5 degree split in caster with the lead going to the left to comp for the road crown. Caster lead will be the smaller number and a camber lead would be to the larger number. Also I'd make sure you get a printout with before and after specs so you know where it was to start with.

[dragginmetal]

I replaced ball-joints on a '96 s10 i used to own and didn't get one of coil springs seated in the LCA right. It caused a similar problem to what you have.

[67carry-all]

Thanks for the feedback and tips, especially regarding the caster/camber. I'll take it back to the shop next week and also have a look at the spring mountings. I think the wiggle was there prior to the rotation; subtle enough that it's one of things you become aware mostly after you're paying extra attention to the suspension.

[kornfed]

Did they replace the control arm bushings? Sometimes if they aren't tightened properly, it'll have a different preload from left to right. If this is the case though, it should have shown up on the camber reading

[67carry-all]

Control arm bushing were not replaced - didn't think about it at the time, now I'm wondering if I should have had it done. How do you know when they need replacing?

I looked at the spring seating. As far as I can tell, they seem to be seated ok, BUT, the angle of how they are sitting seems very different comparing driver and passenger sides (driver's side, second photo, spring seems more at an angle); truck seems to sit level, though - see pics. Driving at highway speeds, going over a small bump in the road, seems like the pass side is softer (or driver side harder) and the truck bounces a little unevenly, almost diagonally. Not super dramatic but a little hard to tell. Any thoughts on how the springs look in the pics?

[67carry-all]

Ok, truck pull, uneven bounce, and wiggle finally diagnosed and fixed. With mutual scheduling and time issues, didn't get back to the original shop and I took the truck to another shop that's more familiar with older vehicles. Shop owner was checking under the truck and then came to the......... tires! Bigdav was on it from the beginning. The two left tires had "bubbles" or, to me, bulges in the tread section. These were causing the wobble at low speeds, the pull at all speeds, or as the mechanic described, the left front tires was pushing the truck to the left. The tires were basically failing and also causing the uneven bounce at hwy speeds. The two bad tires being on the same side of the truck helped explain why rotating the tires front to back made only a minimal difference. I checked the date code on the tires - they were 12+ years old. I bought them new maybe 10-12 years ago and by tread depth had maybe a few more thousand miles to go. It was an interesting learning experience - I've had tires wear out but this was the first time I'd had a set fail - glad they didn't totally give out on the road.

New tires are now on and rides like a new truck - tracks straight, takes the hwy bumps as if they're not even there, and no wobble. As a bonus, the manual streering now feels like power steering in comparison.

Hope this info helps others - I know I'll be paying closer attention to tire date codes in addition to tread depth and will change out tires that are approaching the 10 year mark (if they make it that far). Thanks again to all who chimed in with ideas.

[ncoonen]

Originally Posted by 67carry-all

New tires are now on and rides like a new truck - tracks straight, takes the hwy bumps as if they're not even there, and no wobble. As a bonus, the manual streering now feels like power steering in comparison.

Hope this info helps others - I know I'll be paying closer attention to tire date codes in addition to tread depth and will change out tires that are approaching the 10 year mark (if they make it that far). Thanks again to all who chimed in with ideas.

I have no tech to add but want to reinforce the moral to this story - old tires suck. I have had the "old tire conversation" several times with guys who are vaguely unhappy with their old cars/trucks but don't want to replace old tires that aren't worn out. Once you put properly balanced fresh tires on *any* vehicle with old tires, you'll notice the difference. A couple years ago I drove a new-to-me 1961 Corvair Lakewood from Oakland, CA to Chicago. We stopped in Winnemucca, NV after the first leg. The following morning, my buddy and I stopped at Les Schwab Tire and get a new set of King Star (chinese) 13" radials to replace some really sketchy old tires. The car rode like new - smooth, quiet, no vibrations!

Retire your old tires!...ned.

[INSIDIOUS '86]

In addition. Some companies will not re mount tires more than six years old. For these reasons
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[wraprail]

^^discount tire cries about mounting "old" tires. Bunch of chicken ****s. I no longer deal with them cuz of that.
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[cory d]

some people only look at tread depth. ever drive on some old, hard plasticy tired in the rain? its fun but i dont want to do it every day

[JointTech]

mine was acting weird as well. While I was in the process of buying new tires and wheels I came out one day to find this. Glad it happened in the parking lot. A few days later the other side did the same thing. weird.