Slant Six Forum :: Moog "problem solver" offset upper control arm bushing orientation

Quote:

You want positive not negative caster ... I still don't think you want 7* of it though and mcnoople
There's no way to get "cross caster" on both sides" that is the difference between left and right readings.

I did have a typo in my post so it may have been confusing since it contradicted itself.

I don't think I used the term cross caster. Ideally cross caster is close to zero, with maybe a little more positive caster on the drivers side to compensate for road crown. I agree with positive caster good, negative caster not good. And I also wouldn't suggest running 7 degrees of positive caster if it is even possible.

I have 5 degrees of positive caster on my valiant with 24:1 manual steering. You have to put some effort into turning and would not suggest above 5 even with power steering.

Author:	volaredon [ Thu May 28, 2026 2:35 pm ]
Post subject:	Re: Moog "problem solver" offset upper control arm bushing orientation
The frame slope and different caster loaded vs unloaded wouldn't apply near as much to a short bed truck. A long bed or even a club back or crew cab cab and chassis would be even more difference because of the excess length vs a reg cab short bed. The longer truck is a longer "lever".

Author:	mcnoople [ Mon Jun 01, 2026 1:12 pm ]
Post subject:	Re: Moog "problem solver" offset upper control arm bushing orientation
My memory of the short d100 is that it is a 114 inch wheelbase. That is not much longer than a dart(wheelbase). I also remember curb weights of less than 4k. Basically, it the size and weight of a fat charger. If you can get 5 degrees of positive caster on both sides with 1/2 degree of negative camber on both sides it should drive nicely. I remember the specs on the car side being between -1 to +2.5 for caster, so I would be very surprised to see much more adjustability in the cam bolts on the trucks. On the offset UCA bushings you want to orient them to push the upper ball joint rearward. So the forward bushing on both upper arms is biased/offset toward the outside of the vehicle. The rearward bushing on both upper arms would be the opposite. This means that when peaking at the installed bushing in place on the vehicle: the forward upper bushings will have more rubber outboard of the bolt and the rearward bushings will have more rubber inboard of the bolt. I also remember mopars idea of loading during alignments was 150 lbs in the drivers seat on cars. I have never seen what applies to trucks for loading. editing a misused "caster" when I meant camber...

Author:	Reed [ Mon Jun 01, 2026 10:33 pm ]
Post subject:	Re: Moog "problem solver" offset upper control arm bushing orientation
Thanks, McNoople. I can get over 7 degrees negative caster on the passenger side, but I can barely get 5 on the driver's side. I was eyeballing the UCA bushings and I think I got one or both of the driver's side UCE offset bushings installed incorrectly. I have noth sides set the same for now, so I will let it be until I get some more time to tear into it again.

Author:	volaredon [ Tue Jun 02, 2026 3:41 am ]
Post subject:	Re: Moog "problem solver" offset upper control arm bushing orientation
You want positive not negative caster ... I still don't think you want 7* of it though and mcnoople There's no way to get "cross caster" on both sides" that is the difference between left and right readings.

Author:	mcnoople [ Thu Jun 04, 2026 10:59 am ]
Post subject:	Re: Moog "problem solver" offset upper control arm bushing orientation
Quote: You want positive not negative caster ... I still don't think you want 7* of it though and mcnoople There's no way to get "cross caster" on both sides" that is the difference between left and right readings. I did have a typo in my post so it may have been confusing since it contradicted itself. I don't think I used the term cross caster. Ideally cross caster is close to zero, with maybe a little more positive caster on the drivers side to compensate for road crown. I agree with positive caster good, negative caster not good. And I also wouldn't suggest running 7 degrees of positive caster if it is even possible. I have 5 degrees of positive caster on my valiant with 24:1 manual steering. You have to put some effort into turning and would not suggest above 5 even with power steering.

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Author:	Reed [ Fri Jun 05, 2026 10:51 pm ]
Post subject:	Re: Moog "problem solver" offset upper control arm bushing orientation
Sorry, I meant + caster (upper ball joint towards the rear of the vehicle).

Author:	volaredon [ Sat Jun 06, 2026 6:40 pm ]
Post subject:	Re: Moog "problem solver" offset upper control arm bushing orientation
Quote: Quote: You want positive not negative caster ... I still don't think you want 7* of it though and mcnoople There's no way to get "cross caster" on both sides" that is the difference between left and right readings. I did have a typo in my post so it may have been confusing since it contradicted itself. I don't think I used the term cross caster. Ideally cross caster is close to zero, with maybe a little more positive caster on the drivers side to compensate for road crown. I agree with positive caster good, negative caster not good. And I also wouldn't suggest running 7 degrees of positive caster if it is even possible. I have 5 degrees of positive caster on my valiant with 24:1 manual steering. You have to put some effort into turning and would not suggest above 5 even with power steering. Nope. Less caster on driver side. Not more.

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