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View Full Version : UCA lengths not the same?



nate
05-24-2005, 07:42 PM
This has me puzzled. Radius arm setup. My driver's UCA is 15 1/2", my passengers is 15". They are adjustable, but for them to bolt up, that's what I have to put them to. The arms mounts at the same place on the LCA, and the axle is square under the Jeep as best I can tell (tape measure and plumb bob)
Just the mounts on the axle seem to be 1/2" off. Does that make any sense? I could push the passengers out to 15 1/4", and I'm sure I could get the driver's to 15 1/4"... make sense to do that?

Nordic1
05-24-2005, 07:43 PM
LCA cam bolts on the axle?

nate
05-24-2005, 07:46 PM
Nope, XJ axle. Everything measures out the same on the lowers, etc, just from the UCA mount on the lower to the UCA mount on the axle is 1/2" off between the 2... and the mounts on the lowers are in teh same place.

BigDaveZJ
05-24-2005, 08:36 PM
Could just be a tweaked unibody too. I'd say set it to whatever works best and run with it.

mtnzj
05-24-2005, 08:37 PM
i noticed the same thing when i installed my JKS arms, the factory mounts aren't the same on my zj, so the axle has always been about 1/2 inch further forward on pass side

Jim311
05-24-2005, 09:12 PM
The alignment rack doesn't lie!


:finga:

nate
05-25-2005, 06:47 AM
Yeah it doesn't, but I won't be putting the Jeep on the rack anyway, I do my alignments with a tape measure and by eye and I've never had problems. The Jeep sees like 1000-2000 miles a year anyway.

I just find that the UCA being differenct lengths is weird. My unibody could be tweaked, but it doesn't matter since the UCAs are connected to the lowers. The only measurement that isn't the same is from the UCA mount on the axle to the one on the LCA... so for some reason the mount is 1/2" off on the axle or something?

JeepinHank
05-25-2005, 08:54 AM
You got a license to operate that tape measure? :yawinkle:

Seriouisly, could the tubes be tweaked or twisted a bit? Beyond that, I don't know - I'm only running a single UCA on the drivers side.

I'd just set it to where its good for you, and run it.

nate
05-25-2005, 05:07 PM
Yeah license haha. I looked at it, and was like, boy that looks like it's about 1/2" off... tape measure said the same thing too... Calibrated eye is what I have :mrgreen:

The Jeep the D30 came from was just a street Jeep, so I can't imagine the tubes got twisted, though who knows huh? The caster is the same on both knuckles, so I think it's ok. I'm going to try and set them to 15 1/4" and get them in there. I know before with RE short arms on my other axle I always had to fight to get all the arms in place. With the uppers on this, I just adjusted them to slide right in... I think maybe need to "preload" it a bit... Dunno, just seemed weird and I was sratching my head last night.

Oh, for anyone that wants to call a D30 wimpy junk, that fucker is heavy when it falls off a jack right on my foot. Figure maybe 100-150 lbs? I know I am able to carry it around the garage, so it ain't too bad. BUT, I still blacked out from the pain. I think I may have broken some bones, going to the ER in a little bit here. The nut for the lower ball joint is what slammed my foot.. very very painful to bend my toes right now, and I don't dare remove my boot.

chadjans
05-25-2005, 11:06 PM
Axle tube is twisted. Or just force the thing to have equal lengths. With my jeep on the ground and the arms set to equal length I have to force the bolts to line up.

Chad

nate
05-25-2005, 11:29 PM
The thing though is the knuckles both have the same caster, so "in theory" it wouldn't be twisted. I dunno, maybe the mounts aren't exactly in the same spot, maybe I just need to get on the short bus. haha.