adjusting control arms

[88flexj]

The pinion angle on my front axle is a little low. Can I simply lengthen the upper control arms to bring up the pinion, or do i have to shorten the lowers at the same time? I have the non disco high pinion dana 30 front axle. will the low pinion angle cause a bad vibration at about 60 m.p.h.? The pinion is about 1.5 degrees low. Here is a little more history. I recently swapped in this axle. The old axle was also a h.p. dana 30 non disco. There were very minor vibes before the swap, and i didn't change any adjustments. I know the vibes are in the front, because I removed the front driveshaft, and it was smooth as silk. I suspect the vibes were in the front driveshaft, which is being replaced. But what about the pinion angle? I have also read that when going to lower gears, 355s to 456s, that vibrations are magnified. Is this true? I did a search couldn't find these answers. Thanks.

 

[Pietro]

only adjust the uppers to set pinion angles. Lowers are for establishing wheelbase. yes, either one will change it but use the uppers if you can. putting lower gears in causes the driveshaft to spin a certain amount more while traveling at the same speed. I noticed that mine has vibes at certain speeds from the front. I just deal with it, it is only slight. Your front pinion angle should be pointed straight at the t-case yoke.

 

[XJ_ranger]

here's how i did it:
http://www.opiebennett.com/upperdrrveshaft.htm

do you have adjustable arms?

there are also factory alignment shims that can be purchased that will move your LCA's forward or backward to set pinion angle. They sit in the LCA pocket...
might be worth looking into if you dont have adjustable arms...

 

[88flexj]

Thanks for the replies guys. Yes, I have adjustable uppers and lowers. I will bring up that pinion and see if that helps. Thanks for the help and i will keep you posted.

 

[DaffyXJ]

Yeah, adjust the uppers. But keep in mind you're also going to be changing the caster. effects the return to center after a turn.

 

[88flexj]

By adjusting the upper control arms to set the pinion angle, will I have to get a front end allignment again?

 

[DaffyXJ]

Technically, rotating the pinion and changing the caster is perfoming an alignment.
No you shouldn't. changing the caster shouldn't adversly effect the tow. But you can measure it just to be sure.

 

[Pietro]

i wouldn't worry about the alignment unless your runnin a set of very expensive tires. After i dialed in my pinion angle (5" of lift) I had about 1 degree of positive caster in the front, and it would improve if those damn re rear springs would settle alittle more, but i still find it very driveable. sure, it doesn't handle like stock, but i would give up a little drivability for no frontend vibes

 

[XJ_ranger]

Your most Recent Post:

i wouldn't worry about the alignment unless your runnin a set of very expensive tires. After i dialed in my pinion angle (5" of lift) I had about 1 degree of positive caster in the front, and it would improve if those damn re rear springs would settle alittle more, but i still find it very driveable. sure, it doesn't handle like stock, but i would give up a little drivability for no frontend vibes

what changed from this post - about 12 hours ago?

only adjust the uppers to set pinion angles. Lowers are for establishing wheelbase. yes, either one will change it but use the uppers if you can. putting lower gears in causes the driveshaft to spin a certain amount more while traveling at the same speed. I noticed that mine has vibes at certain speeds from the front. I just deal with it, it is only slight. Your front pinion angle should be pointed straight at the t-case yoke.

be consistat with lies about your rig or someone will caatch you...

 

[RCP Phx]

i wouldn't worry about the alignment unless your runnin a set of very expensive tires. After i dialed in my pinion angle (5" of lift) I had about 1 degree of positive caster in the front, and it would improve if those damn re rear springs would settle alittle more, but i still find it very driveable. sure, it doesn't handle like stock, but i would give up a little drivability for no frontend vibes

Driveable and safe are two different things,with 1* of castor its likely you have neither!

 

[Pietro]

i guess the hunter alignment machine lies then, go pick a fight with someone else asshole, i am not getting into a piss match over a caster spec.

yeah, like the quote says, i have no drive line vibes. yes at certain speeds i can feel the front shaft slightly but not a large enough vibe to be a problem

xjranger, go get laid or something rather than stare at a computer monitor picking apart every word i say


BTW, a set of swampers will make a jeep have poor steering capablities regardless of how much caster it has
negative caster isn't bad, some vehicles actually have negative caster when equipped with no power steering, it makes it easier to drive. guys called engineers, they make it like that for a reason. yes, you shouldn't have negative caster on a jeep when it is designed to run with around 7 degrees positive, as long as it is still on the positive side, i wouldn't worry about it

 

[jrsxj98]

Quote:
Originally Posted by Pietro
i wouldn't worry about the alignment unless your runnin a set of very expensive tires. After i dialed in my pinion angle (5" of lift) I had about 1 degree of positive caster in the front, and it would improve if those damn re rear springs would settle alittle more, but i still find it very driveable. sure, it doesn't handle like stock, but i would give up a little drivability for no frontend vibes

Quote:
Originally Posted by Pietro
only adjust the uppers to set pinion angles. Lowers are for establishing wheelbase. yes, either one will change it but use the uppers if you can. putting lower gears in causes the driveshaft to spin a certain amount more while traveling at the same speed. I noticed that mine has vibes at certain speeds from the front. I just deal with it, it is only slight. Your front pinion angle should be pointed straight at the t-case yoke.


naughty naughty your lies are catching up to you again............

 

[Pietro]

you guys have sandy vaginas tonight

what is the problem here...
read both posts

first...
mine has vibes at certain speeds

second post...
i would give up a little drivability for no frontend vibes

where did i say that i have NO front driveline vibes???

 

[Yucca-Man]

Dang somebody is grumpy tonight...sounds like it's almost time for a time-out...

 

[Pietro]

yeah i guess it is time for some sleep

 

[XJJPR]

Done