Alignment journey

[JAF]

74 Bronco. 3 1/2" lift w/duff long arms. Took it in for the 1st alignment:

Alignment shop set toe.

Took it back in the shop and changed C bushings fron 4 degree to 7 degree. Installed a 1.5 degree camber shim on right side knuckle (dialed for 1.5 degrees positive).
Back for 2nd alignment:

Alignment shop made no changes, I took it home.
Didn't understand how 1.5 degrees of correction took Right camber from -0.8* to +1.2*?? But, anyway, changed camber shim position. Dialed it from 1.5* to halfway between 1/2* and 5/8*.
Was happy to see caster above 4*. But, I think its curious that arms with 4.25* built in, and installed with 7* bushings only nets 4*??
Back to alignment shop:

Alignment shop set toe.

Don't understand how I lost 0.3* of caster. Don't understand how I lost 0.2* of camber on the left side.

I feel like I'm trying to hit a moving target. Or, more likely I don't completely understand the interrelationship between camber and caster.

On a scale of 1 to 10, I'd say the ride quality is a 5. Any insights or wisdom you guys would care to share would be greatly appreciated.

 

[m_m70]

Not sure on the alignment discrepancy. As far as ride goes, the air pressure plays a huge role in my ride quality. Mine like 27lbs in the front and 26 in the rear. Anything over 30 my front wanders. Check your u-bolt and your rear shackle torques and make sure they are tight. I'm sure some guru's will chime in on your alignment specs......

 

[JAF]

Thanks m_m70, I’m running 33x12.5 KO2’s with 28lbs all around. I’ll try your settings and see…
Also, I’ll go back and re-torque everything. It’s a fresh build, so maybe things are settling?

 

[m_m70]

It’s a fresh build, so maybe things are settling?

I was surprised how much the rear needed adjustment after a couple hundred miles. Hope it's that simple for you!! Good luck!

 

[Torkman66]

I worked a long time doing a lot of what you have done. I only had a 2.5" SL, added 7* bushings, and added 1.5* eccentrics. That gave me about 4* caster. Like you, it drove 5 out of 10. Not relaxed driving, especially when on a road with some dips. Just not a great driver. I think the factor Dana 44 was likely not to design specs. That's all I can think of because raising it 2.5" should not have thrown caster off so much. Obviously, if I were to do it again, I would cut and turn the Cs to get caster perfect. But because my axle was already powder coated and show ready, I removed the eccentrics and installed the Duff adjustable arms. I was able to easily get caster to 8* and it could go further if needed. While true that the pinon is now at 15*, this rig will never see 4 wheel drive and if it does, it will be slow without any extensive articulation. Drives like a normal rig now. One handed down the road, straight, returns nicely to center. You can get a digital angle gauge and since you now know the caster from your last alignment sheet, use the gauge on the flat part of the lower C and move it around until you read the exact caster on the sheet. Mark that spot. Now when you make any adjustments, you can just put the gauge back in the same spot and see what caster is without having to take it to shop.

 

[JAF]

Update: Went thru and re-torqued everything. Played with tire pressure. No noticeable difference. Tore down the front end and stripped the housing, cut off C's and turned 7*. welded back up and painted.

 

[JAF]

Got the front end back together with 4* bushings and it does drive better, but still not great. Took it back to alignment shop.
I now have the 8* of caster that I wanted, but almost a degree of cross caster in the wrong direction. Also, the alignment shop suggested changing the steering to TRO to eliminate some angle in the drag link, and to get things more parallel.

 

[JAF]

Here's a pic of current TRU steering. I guess the track bar and the drag link are off a little, but I didn't think it was that bad.....anyway thanks to the guys at WH's i got some shims and a tapered bit to flip things around.

 

[JAF]

Well, the tapered bit worked great and the shims made the conversion pretty easy. While it was apart, 0.5 degree inserts were installed on the upper ball joints. Idea was to remove half a degree of caster from the driver's side and add half a degree to the passenger side. Here's the TRO:

 

[JAF]

It definitely drives better. I used a set of bolt on toe-in brackets to set the toe to 1/4" total. While I had the brackets bolted to the hubs I turned them vertical and put an angle finder on them to get a rough camber measurement. It read 1.3 degrees on the right and 2.5 degrees on the left. That's quite a change from where it was at the alignment shop, I'm wondering if changing caster can affect camber? Anyway, got an appointment to get it back on the alignment rack and see where its at.
Thank you to everyone who has responded and shared their insights with me!

 

[ksagis]

Edit: confused, the alignment sheet shows 0.06 deg of total toe but then you mention “bolt on toe brackets”?

 

[Torkman66]

First, nice job! Those inserts can affect both camber and caster. If you are using them to offset caster, then they will absolutely change camber in an offset pattern as well. For example, if you place the entire offset of the insert toward the rear, you are affecting caster only. If you set it all at 12 o'clock, you decrease caster only. If you put the offset at the 9 or 3 o'clock position, you are affecting only camber. Anywhere else has a combination effect on both caster and camber. If for example you set the PS offset at 2 o'clock you'd be decreasing caster a bit and moving top of wheel out a bit (camber). If you then did the opposite on the DS, you would be making a double change to camber between the wheels. Hope that makes sense. Bottom line is that if the offset in the insert is not at 12 or 6 o'clock, then it is affecting the camber. If you got 1/2 degree inserts and put one on the DS at the 12 position you would decrease caster 1/2 degree on that side and not effect camber (assuming you have it exactly at the 12 position. If you then put in a 1/2 degree insert on the PS at 6 position, you would increase caster 1/2 degree. That would get you very close. But placing the offset in the insert anywhere but 12 or 6 begins affecting the camber. If it were me i'd just add a single 1/2 degree increase to the PS. @jamesroney will read this and need to take a few deep breaths before he explodes, but will then settle down and offer you the right way to dial this in. Listen to him. James?

 

[JAF]

Edit: confused, the alignment sheet shows 0.06 deg of total toe but then you mention “bolt on toe brackets”?

Ksagis, after the alignment, when I swapped from TRU to TRO I had to reset the toe. I did this in the shop with toe-in brackets.

 

[JAF]

First, nice job! Those inserts can affect both camber and caster. If you are using them to offset caster, then they will absolutely change camber in an offset pattern as well. For example, if you place the entire offset of the insert toward the rear, you are affecting caster only. If you set it all at 12 o'clock, you decrease caster only. If you put the offset at the 9 or 3 o'clock position, you are affecting only camber. Anywhere else has a combination effect on both caster and camber. If for example you set the PS offset at 2 o'clock you'd be decreasing caster a bit and moving top of wheel out a bit (camber). If you then did the opposite on the DS, you would be making a double change to camber between the wheels. Hope that makes sense. Bottom line is that if the offset in the insert is not at 12 or 6 o'clock, then it is affecting the camber. If you got 1/2 degree inserts and put one on the DS at the 12 position you would decrease caster 1/2 degree on that side and not effect camber (assuming you have it exactly at the 12 position. If you then put in a 1/2 degree insert on the PS at 6 position, you would increase caster 1/2 degree. That would get you very close. But placing the offset in the insert anywhere but 12 or 6 begins affecting the camber. If it were me i'd just add a single 1/2 degree increase to the PS. @jamesroney will read this and need to take a few deep breaths before he explodes, but will then settle down and offer you the right way to dial this in. Listen to him. James?

Torkman66, the eccentrics are installed in the 6 and 12 positions as you described. My thinking was to pull .5 out of the left side and add .5 to the right side to get 8.34 left and 8.48 right (thinking a slight cross caster favoring the right side would be ok).

 

[Oldtimer]

With TRO, wheels turned hard right, how much clearance between tie rod and stud for axle end of track bar?

 

[JAF]

With TRO, wheels turned hard right, how much clearance between tie rod and stud for axle end of track bar?

IIRC the tie rod passes below the stud/nut by 1/4-3/8". I think this is affected by the F150 knuckles.

 

[EPB72]

Torkman66, the eccentrics are installed in the 6 and 12 positions as you described. My thinking was to pull .5 out of the left side and add .5 to the right side to get 8.34 left and 8.48 right (thinking a slight cross caster favoring the right side would be ok).

cross caster favoring the right side would be ideal, most vehicles specs are geared that way , But would I chase those #’s probably not,,

 

[jamesroney]

IIRC the tie rod passes below the stud/nut by 1/4-3/8". I think this is affected by the F150 knuckles.

@Oldtimer Hi Geoff, It's really hard to know how this applies to yours without knowing EXACTLY how much he rolled the inner C. He said *7 degrees, but I don't know what that means. I ASSUME it means that he took the existing inner C, and rolled it back an additional +7 degrees, but you can see how that gets difficult to measure once you knock off the C's.

This is why I never speak in terms of incremental caster. Because when all the parts are laying on the floor...you don't have any idea how much "more" of anything exists. "7 degrees more..." only works when you leave one side on while you work on the other.

I also don't know which knuckle he rolled back wrong. The issue is that the height of the tie rod is related to how much caster you roll into it. If he posts the pinion angle, (or diff cover angle) I can back calculate it.

Here's a pic of an F150 knuckle that is TRO, with 7 degrees of caster at 14 degrees of pinion. (and yes, the tie rod hit the track bar stud)
And another one with an EB drum knuckle that is TRO with 7 degrees of caster at 14 degrees of pinion. (I think it went OVER the stud)
The one without a disc rotor shield is the F150 knuckle.

I don't think about the drag link stud much anymore, because at 3.5 lift, I always run the WH track bar riser. But your 68 is only 2.5 lift. So you would have built it less intrinsic caster. I don't think any of this applies to the 76-77 EB knuckle, because those arms are in a different place. I can't remember if you are EB drum knuckle, EB disc knuckle, or F150 knuckle.

 

[Oldtimer]

In my case, I have 77 Bronco knuckles with TRO, and the tie rod was dead center on the track bar stud. Needed riser bracket to fix linkage geometry, so stud is no longer a interference point.

 

[JAF]

In response to question above: The C’s were cut and turned 7* over stock.
Update:
Got it back on t alignment rack.
Camber at 1.2*/1.2*
Caster at 8.0*/8.2
Toe at 0.31*
SAI at 8.7*/6.9*

I’m concerned by the cross sai. Could adding .5* eccentrics for caster correction (neg .5* on left and pos .5* right) cause this?
Right now it drives pretty good. 100% better than where I started. Do I need to worry about cross SAI?