How to do an Alignment at Home

yeah technically if you are on a flat surface it shouldnt matter, and you can check your angle finder on one side, zero it on the ground, move to the other side on the ground and see what it says, if its flat is SHOULD be still zerod.

 

@nd4spdbh your amendment to measuring caster is spot on! I zeroed the angle finder behind each tire, mounted it to the wheel with electrical tape, then turned the wheel 1.25 turns each way. I did it 3 times on each wheel for an average, but each time the results were literally identical.

My caster is 4.0 on the drivers side and 3.7 on the passengers side. I'm going to increase the passengers side to about 4.2 for the correct cross caster for road crown, reset toe, and call it a day!

Centered:

1.25 turns right:



1.25 turns left:

 

nice!

technically you only need to zero out on the ground when referencing camber.

For the caster, turn the wheel out (left if measuring drive side), zero the angle finder on the vertical, turn it back in the same amount (1.25 turns from center in this case) and the angle finder calculates the difference for ya.

 

Slight bit of confusion on my part.
So I turn the wheel 1.25 turns out from center, zero the angle finder, then turn it back 1.25 turns to center and the reading is my caster on that wheel? Or do I continue 1.25 turns in for the final reading?

Edit: disregard. After reading your post again, I see that I need to turn 1.25 turns out, zero the angle finder, then sweep all the way through to 1.25 turns in to get the caster reading.

 

Yup you got it +- 1.25 turns from centered.

 

I kept missing the "+-"

 

Do you have the SPC Lightracing uppers? I've found that with my lower cams maxed for caster and my SPC uppers rotated one degree positive from neutral, there's .5 degree of cross caster and it's backwards (5.4 degrees drivers side, 4.9 degrees passenger side). To correct this, I plan on rotating the passenger UCA one more setting positive for an additional .75 of caster. That will give me final numbers of 5.4 drivers and 5.7 passenger, with across caster of .3.

I'm wondering if having the uppers on different caster settings is ok.

 

Hey I'm just wondering what your technique is for adjusting the upper ball joint? Are you lifting the vehicle each time?

I have a shop that lets me use their alignment machine but what gives me trouble is adjusting the SPC UCA's. Every time I loosen the nut it slides in too far and it's damn near impossible to slide it out without lifting the truck which means I have to reset the machine.

I also find that when adjusting my camber on the machine, my caster readings do in fact change. Same goes for toe, it changes the readings for my camber and caster. I'm not sure if this is related to the way the alignment machine calculates the readings on the fly.....or if I should be rolling the truck and resetting the machine after each adjustment (caster, camber, toe)...or if the idea that these measurements don't play off each other is incorrect....

Any advice/insight would be much appreciated!

 

You need to at least relieve some of the weight by jacking the truck up some; as you said, it's almost impossible to slide the upper ball joint with the full weight of the front end pushing on it. And yes, adjusting any of the parameters changes the other, except if you just adjust toe by itself.

The way I do it is camber, then caster, then finally toe.

 

Thanks for the quick response! That's interesting as almost all of the threads on TW recommend caster, camber, then toe. I'll give your order a try this evening and see if it works out better for me.

 

you have to do camber first. it affects caster directly

 

Yeah you gotta unload the front to be able to slide that ball in and out. Its likely due to how that machine works and how the truck settles back down without properly settling but i saw no difference in caster numbers depending on how my camber adjustment was done at the upper ball joint on the spc arms (obviously not spinning the ball forward or back). I do know that i would always make the change, back the truck up 15 or so feet, then pull forward to get the truck to settle properly.

I think i posted more details of my methods above, but with spc arms it was, caster first (getting both LCA's lined up at the same starting point, gross caster adjustment done at the top by spinning the upper ball to the same position either side, then fine caster adjustments via LCA, then camber via upper ball joint, then toe)

 

Ok good to know. Thanks pal! I think I've got a good game plan now when I go back to fine tune things.

 

Just to give ya another idea for slippery pads to put under the tires. I found them big green contractor trash bags work great. I just pull a couple off the roll and fold one per tire that just fits under each. Its something most every one has and they are slippery just step on one .

 

I did my alignment last night with similar results. My LCAs are maxed for caster/wheels as far forward as possible. The UCAs are at setting D (+2*). Passenger side ended up with 4.9* and driver ended up at 4.4* of caster.

I’m probably gonna bump the passenger side UCA to setting E (+1) to drop the caster to 3.9* on the passenger side. That way I have the cross caster at .5* the correct way.

What did you end up doing?

 

Funny you should ask. I ended up redoing the alignment (great thing about doing it yourself vs paying every time).

The reason was I just had too much caster. Some say you can never have enough caster, but I can debunk that myth. Too much caster (closing in on 5 degrees) causes excessive bump steer and a very harsh ride as the angle of the suspension stroke makes it harder to compress, thus making the front feel stiffer and more jarring.

I've experimented with caster angles between 2 and 5.5, and found my sweet spot at around 2.5 degrees of positive caster. I have both uppers set to neutral, and tuned the LCA alignment cams accordingly. I have .2 degrees of cross caster and .2 degrees of cross camber, and it drives phenomenally.

 

Gotcha.

I was at right around 2.5* of caster previously and going up to almost 5* is a noticeable difference. I’m probably gonna drop down to somewhere near 3ish*. I’ll reset the uppers at setting E and fine tune with the alignment cams to set the caster.

I need to find a happy medium between caster and clearance.

 

Well. After driving with the caster at almost 5*, I couldn’t stand it. It’s too much caster. The suspension feels like it’s binding and the ride is overly rough.

I reset both upper ball joints to position “E”. I still have more than enough clearance with the 285s I just installed.

The caster is now 3.4* on the driver side and 3.9* on the passenger side. Not ideal yet, but rides much better. I still needs to set the passenger side down to 3.1*/3.2*.

New question, which cam would I be better off spinning to set the caster at the LCA? Or would it be best to spin each one a little bit?

Picturing the LCA, it makes sense to spin the rear cam to pull the wheel back a bit. Is this correct?

 

You have to spin them both to make the caster change.

 

Realigned again today. Not sure what I was thinking the other day but I want he right (passenger) caster to be higher than the driver side, not the other way around like I posted.

Today -

- Both ball joints set at setting “E”.
- Control arm cams maxed for caster (rear out, front in).

Aligned.

Driver (left) side -

Caster - 3.3/3.4*
Camber - -.5*

Passenger (right) side -

Caster - 3.8/3.9*
Camber - -.5*

Toe - 1/8” toe in

Cross caster - ~.5* to the passenger side.

Pretty happy with this setting except my steering wheel isn’t centered. It’s just a hair off - like 1/2 a tie rod spin off. I’m gonna tweak that tomorrow and maybe add a hair more negative camber to the passenger side - bring it up to like -.7*. Or would I be better off dropping the driver side down to like -.3*?

Thoughts on these numbers?