upper A-arm adjustment

[Custom 68]

Hey all, this may get long but hopefully not too confusing. I recently replaced all the suspension parts on the front end of my truck and went to 2 ½ inch drop spindles and stock height springs. My question is on the upper A-arm connection. The rod that goes from front to rear that the studs on the frame go through seems like I remember can move by screwing it front to rear. How are these set correctly? I remember putting them together and bolting everything up. The truck has been aligned but I am not happy with it. I am going back in to use some of the new values I found on this site recommending more positive caster.
Before I go back in I want to know if these are to be adjusted in some manor?
I hope you understand my questions…
Thanks in advance
Dave

[67ChevyRedneck]

I took my truck into a good shop that did nothing but alignments, 5K miles on it since and still handles great with no pull or vibrations. I purchased new tires at the time. What are you not happy about? Did you replace the tires/rims or have them balanced? Could you have a bent rim or crappy tire?

Anyway, there are metal shims behind the upper A arm "rod" you are asking about. Those are used to adjust the camber (be replacing or adding them.) When I rebuilt my suspension I taped them together and put them in the same way I took them out. With the drop spindles no suspension geometry should have changed at all, so I'm not sure what your problem could be

[Custom 68]

First the tires and wheels are my “old” ones they are 275/60/15 but they were rebalanced and should be ok.
The truck seems to want to wander more than I had hoped. It doesn’t really pull but seem like I am somewhat fighting the straight ahead tracking. I am hoping adding a bit of positive caster will help. The front end seems light.
I installed everything back the way it was but it seems like (going by memory) that you could move the mounting “rod” to change the upper location. And yes when they aligned it last time there are new shims in there.
Part of this may just be me I have a newer Tahoe that is quiet and drives down the road really nice, I may be expecting too much but I am going to try another adjustment to see if it helps.
Thanks
Dave

[JustLiveIt]

I believe that the shaft should be centered front to rear in the A arm. Just measure and adjust until it is centered in the A arm.

[Custom 68]

Originally Posted by JustLiveIt

I believe that the shaft should be centered front to rear in the A arm. Just measure and adjust until it is centered in the A arm.

Humm now that you say that I think I remember doing that, something just got me questioning it, I may pull it into my shop and take a peek the best I can.

[neonlarry]

Wandering can have several causes. One could be a loose steering box. Ther other is toe, what did you have the front toe set at? If you don't know you better find a new alighnment shop, all decent shops will give you a complete printout.

[Custom 68]

Originally Posted by neonlarry

Wandering can have several causes. One could be a loose steering box. Ther other is toe, what did you have the front toe set at? If you don't know you better find a new alighnment shop, all decent shops will give you a complete printout.

Thanks Larry, I think my steering box is tight atleast it seem fairly responsive?
The shop did not give me a print out so I assume it is set a "factory" specs, but yes I have already talked to another shop they seem to have more modern equipment...live and learn.
I hope the weather clears up and I will try to get this done Friday with before and after numbers and a SOTP report.
any other thought is appreciated.
Dave

[Custom 68]

oh yea I did think about replacing my steering box with a "newer" one with the quicker ratio but havent done that. Is there any specific years to look for? are they all compatible?

[neonlarry]

73-87, just check to make sure it is 3½ turns lock to lock.
Also the more toe the straighter it will track, but the harder to get it to turn-in.

[TravisH]

Originally Posted by neonlarry

73-87, just check to make sure it is 3½ turns lock to lock.
Also the more toe the straighter it will track, but the harder to get it to turn-in.

The turn ratio is tighter on 73-87?

[68C15]

IIRC the toe should be between 1/8 - 1/4 inch total. caster about 2 or 3 degrees. camber depends on ride height.
replacing spindles can cause all geometry (toe, caster, camber, steering axis inclination, ackerman angle)to change as this in the most important part. they all depend on the spindle

[qksilver]

plus, a thought, wheel bearings loose?

[Custom 68]

Originally Posted by qksilver

plus, a thought, wheel bearings loose?

well I will check this. I believe they are ok and tight but I better check.

The current alignment was done after the spindle swap, but like I said I dont know how much I trust what they did. here is what was in a previous thread that I am going to try.

have them set it at .3 degrees positive camber +/- .3
3.0 degrees caster (positive) on the left side +/- .5 ... 3.5 degrees caster right side (this adjusts the road crown effect) have them set the front toe and 1/8" positive
this set up works well with power steering, and keeps the tires from wearing
do these numbers look ok?
The factory values are below that I assume mine are set to.
Left Camber is .1
Rt. Camber is .3
Left Caster is 1.1
Right Caster is 1.8
Left toe is .21
Right toe is .20

the weather has been crappy here so I have not had this to the shop I plan on looking at these things over the weekend then taking it in.
I also found a shop that will rebuild my steering box and make it a true 16:1 ratio, he has a lifetime guarantee I dont know how much this will help but I may give it a shot.
thanks again guys
Dave

[LONGHAIR]

........camber depends on ride height.
replacing spindles can cause all geometry (toe, caster, camber, steering axis inclination, ackerman angle)to change as this in the most important part. they all depend on the spindle

I would have to disagree or at least question most of this statement....

There is no valid reason to change the camber based on ride height. You might need to change it because of stiffening the suspension or for replacing rubber bushings with something stiffer. But this is more of a high speed handling issue than anything else.

Toe can change, but should only be minimal with properly made spindles.

Caster, cannot change by changing spindles. Caster is the angle between the ball-joints (from front to back). The spindle is trapped between these points, it cannot change those mounting points.

Camber, should not change....again in properly made spindles. "In theory" a dropped spindle is exactly the same as the stock unit in all of its attachment points except for the height of the wheel bearing shaft area. There are manufacturing/machining tolerances that allow even the factory parts to vary slightly......that is the point of adjustability anyway.

Steering axis inclination????.........caster

Ackerman...........there again, is designed into the parts and is not adjustable. If the spindle is made properly... the length, and angle to the wheel centerline/axis will be the same as the one it is replacing. This is the only way to affect the Ackerman angle/effect with the spindle itself. It is also affected by the steering arm length and pitman arm length, but those are beyond the point of changing spindles.

That being said, if you new dropped spindles cause anything but minor changes in the toe or camber, they are not correct for your truck. Just because it may physically bolt on, doesn't make them "right".