Alignment needed after replacing struts?

c good

Active Member
Original poster
Dec 8, 2011
386
I'm finally going to upgrade my struts to the adjustable 5100 Bilsteins. Since I'm going to use the 2 inch or 2.5 inch lift on them, I'm assuming I'll need to have new Alignment done?
 

TollKeeper

Platinum Donor
Dec 3, 2011
6,401
Brighton, CO
Correct, anytime you change the geometry of how a truck usually rides, an alignment is needed.
 
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Chickenhawk

Hobbyist
Dec 6, 2011
716
Only toe adjustment after changing the tie rod ends. It takes two tape measures, two pieces of stiff aluminum tubing and lots of fine adjustments under the truck.
 

Mektek

Hobbyist
May 2, 2017
580
FL
I tape a piece of string between each of the front and back tires. A piece of sheet metal under the tire makes turning the adjustment nut easy.
Caster and camber can be adjusted with the control arm bracket but hopefully you won't need to change those. Possibly a lift would change the camber too......
Local shops are charging $100 for an alignment. Wasn't that long ago that it was $29.99 with a coupon.
 

Mooseman

Master Blaster
Moderator
Dec 4, 2011
21,859
Ottawa, ON
I used to be able to get lifetime alignment contracts with Sears until they got out of the automotive biz in the early 2000's. Can't find those anymore.

The problem is also finding a shop that can do it right. I was going to one here that charged only $80 but botched it every time. Despite being new equipment and different techs, it was always off. Finally found one that does good work but charges more. I have to get the TB aligned again.
 

aaserv

Platinum Donor
Dec 1, 2019
332
baton rouge,la.
I tried the do-it -yourself online stuff you find on you tube. strings, etc.....didnt go well for me. In fact I made it all but undriveable.
Id be careful about the chain shops also, these trucks are 18 years old or so and thats about the age of the avg mechanic in these places. They've never seen the way these cars have to be adjusted....1st shop I brought it to said there was no adj. on the camber...lol And even when they do figure it out the bolts underneath have to be torqued down at very high level. Its hard to find shops with torque wrenches at all much less trust them to get it done right...

The difference between having it done right and safely is huge.....Take my word on that. Id pay $150+ w no problem to drive away knowing its done right and safe....
 
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TJBaker57

Guru
Aug 16, 2015
2,000
Colorado
Was just wondering if others had tried thier hand at alignments. In the late 70s / early 80s I did a few alignments using Bear equipment so am familiar with the procedure. Just needed to find the equation(s) online.

I find setting the Toe-in to be simple. Been doing this since 1982. I have yet to try setting caster and camber as a home DIY thing using methods such as described by websites like Longacre Racings page. But I have checked my current settings for the Yukon using these methods. The torque on the Trailblazers lower control arm bolts will likely keep me from trying to set anything but I think just for the experience I will check where I am at. I don't have any complaints and I get the full expected tire wear from the Michelins I run.
 

azswiss

Active Member
May 23, 2021
276
Tempe, AZ
I have had excellent results with the string method to measure/adjust toe-in on the Suburban. Working on a smooth, level surface and using a framing square camber measurement is also straightforward. I measure off the rim edge using a caliper depth gauge, and with care & multiple passes I can achieve +/-.01 inches repeatably. I created a spreadsheet that takes the initial measurements, calculates the initial angles, and then calculates the required corrections. To date, I have only adjusted toe-in; I have not had to mess with the combined caster/camber adjustments.
 

Mektek

Hobbyist
May 2, 2017
580
FL
My HFT torque wrench only goes to 170 ft lbs so I added a quarter turn with a breaker bar for the front bolt. I've got my fingers crossed that I got it right.
 
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TJBaker57

Guru
Aug 16, 2015
2,000
Colorado
Working on a smooth, level surface and using a framing square camber measurement is also straightforward. I measure off the rim edge using a caliper depth gauge,


Very similar operation here...

20211030_175929.jpg

The magnets hold the flat rule to the steel framing square with enough force to allow me to slowly bring the business to level and then retain the position for reading. The Bosch level is a magnetic base high precision laser level though I don't need the laser for this operation. The leveling vials are also adjustable for calibration purposes.

I don't have turntables so the wheels sit on two pieces of sheet metal, greased between them like an Oreo and so are free to rotate for caster measurements.

Caster is obtained by taking two camber readings with the wheel turned 20° inwards and 20° outwards then applying a computation and finally adjusting for frame angle.
 

gmcman

Guru
Dec 12, 2011
4,526
@TJBaker57 I did try that exact same technique when I replaced my lower control arm brackets. I personally had no luck as my camber was way off in terms of actual spec and tolerance.
I tightened the bolts enough to move them with a 3lb sledge and a piece of wood.
That doesn't mean you couldn't get it to work and be within spec, I personally couldn't get it within spec.



For a different project much later, I purchased a Starrett model 98 machinists level and used it on my turntable...it's wicked sensitive.

This is the movement from a single piece of laser printer paper, definitely worth it if you are after accuracy.

Screenshot_20211031-154426_Gallery.jpg

Screenshot_20211031-154444_Gallery.jpg
 

azswiss

Active Member
May 23, 2021
276
Tempe, AZ
For toe-in measurements I setup a parallel string arrangement. I place two bars, one in the front and one in the rear. Each bar has two slots cut, one at either end (note: the slots were cut into the bars simultaneously to ensure that they are exactly the same distance apart).

They are set on jack stands raised to set the string at wheel center height. Knowing the front and rear track widths, the strings can be set to parallel by measuring off the wheel centers. For the Suburban the front track width is 1" narrower than the rear so I adjust the strings until I have a 1/2" difference in "depth". Since the string slot distances are identical on the two bars getting one side parallel ensures the other side is also parallel.

From there it is a series of measurements from the fore & aft edges of the rim at the wheel center height.

20211031_114413.jpg


20211031_114537.jpg


20211031_114545.jpg

Camber is checked using the framing square and measuring from the top & bottom edges.

20211031_120704.jpg

Screenshot of the calcs:


Capture.JPG

Since the rear wheels are fixed (i.e. no toe adjustment possible) I use them as the reference for calculating a "Reference Misalign" measurement. This delta (rows 20 thru 27) is then used to calculate the corrected measurements for the front.

Not shown in the pictures are a set of greased linoleum plate pairs for use as turntables.
 
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gmcman

Guru
Dec 12, 2011
4,526
My HFT torque wrench only goes to 170 ft lbs so I added a quarter turn with a breaker bar for the front bold.
Yikes!

I may be way off on my assessment, but 1/4 turn at 170 ft lbs is alot, that's bolt stretch/strip territory.

Not trying to scare you, but I would probably leave well enough alone.

Those nuts are welded in place, a bit of a pita to fix.


I think what @TJBaker57 was demonstrating would work on a flat surface like a garage floor, I tried mine on asphalt and I know it wasn't level. Would definitely be enough to get you to a shop without prematurely wearing your tires.


I tried the DIY toe adjustment when I replaced my steering rack. Drove straight until I went around a turn. Sounded like I was doing a high speed drift...lol, tires howling.
 

TJBaker57

Guru
Aug 16, 2015
2,000
Colorado
This is the movement from a single piece of laser printer paper, definitely worth it if you are after accuracy.

Nice piece! By the specs my Bosch is claimed to be accurate plus or minus 0.25 inches at 75 feet. That would be about 0.0159°. close enough for me!
 
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gmcman

Guru
Dec 12, 2011
4,526
plus or minus 0.25 inches at 75 feet. That would be about 0.0159°. close enough for me!
Heck yeah, nice setup.

The level I had that was short enough to fit on the square, was a relic, and took a little bit to get the bubble to move
 

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