Caster adjustment question?

[williestreet]

So I just replaced both upper control arms. I had it into my local shop to get adjusted and he could not do it. He suggested a couple of other shops, but they are both telling me around a month before they can fit me in.

I am definitely not waiting a month so I decided I would check where it is and see if I can do it myself.
The numbers I found online suggest 0.5 degrees positive Camber, 1/16-3/16 toe, and between 2.5-4.5 degrees caster.

I found the truck to have + 0.3-0.4 degrees positive camber, Caster measured roughly +1.0 degrees. The toe was way too much so I adjusted it to 1/8 ". The truck drives good and with the toe now good and the camber around spec I am no longer worried about accelerated tire wear. At least I can drive the truck until I get the caster fixed.

My plan is to add shims to the front mount to increase caster. I thought there might be a rule of thumb like 1/8" shim will add approx 0.5 degree of caster or something like that. Any suggestions?

I realize I will need to check camber and toe again after I get the caster fixed.
Any suggestions or tips are welcomed.

Truck is a 1980 2wd, stepside

 

[Ricko1966]

If the truck doesn't feel squirrelly on the highway and the caster matches or close side to side,doesn't pull left or right,I'd leave it alone. Caster is a non wear angle and makes the car stable on the highway. If it's stable you're good.

 

[williestreet]

If the truck doesn't feel squirrelly on the highway and the caster matches or close side to side,doesn't pull left or right,I'd leave it alone. Caster is a non wear angle and makes the car stable on the highway. If it's stable you're good.

Yes it feels fine and stable with no pulling. The steering is almost too easy, very little effort if that makes sense. The low caster angle might partially explain that.

I was using a digital angle finder so I picked up a better camber angle tool and plan to measure everything again. I may just leave everything alone as suggested, but I think it would feel better if the steering was just a tad stiffer.

 

[Ricko1966]

That's what caster does,makes it more stable holds a straight line better.

 

[idahovette]

Do NOT put a shim in the front....that will add MORE Camber....you DON'T want that. if you want to try something, remove a shim from the rear bolt. That will increase the caster and won't affect the camber much at all. Recheck the toe after you do this. I would prefer 0 degrees camber, but just watch your tire wear

 

[AuroraGirl]

Do NOT put a shim in the front....that will add MORE Camber....you DON'T want that. if you want to try something, remove a shim from the rear bolt. That will increase the caster and won't affect the camber much at all. Recheck the toe after you do this. I would prefer 0 degrees camber, but just watch your tire wear

MORE CASTER!

Jk, its not necessary and would mean need more assist to steer easily, and on something like this they werent meant to have a lot anyway... but caster is good we want more!

Just like the shopping carts!

 

[krusher74]

I would not bother paying somebody a lot of $'s to get it aligned. if it has slight play in all joints from wear over the years it wont go down the road how they align it anyway. As said above, I'd try to get closer to 0deg camber and 1/16 toe. 4 to 8 deg caster

 

[TotalyHucked]

I don't like even the least little bit of positive camber, ever. It generally makes the vehicle twitchy IMO. I always shoot for 0.5-1* of negative camber (-0.5 to -1.0*), as much caster as I can get and ~1/8" of toe in for a non-performance street vehicle. Positive camber can wear tires just as bad as negative camber, just does it on the outside edge rather than the inside edge.

On my truck with the ~5" of drop up front on stock arms, I think 2-2.5* of negative camber, 4-5* of caster and 1/8" of toe in is where we landed. I couldn't get the camber any better than that without the extended A-arm studs or aftermarket arms. It handled great, had great high speed stability and still got ~25k out of tires with LOTS of highway driving.