noob 4 link question

On a 4 link to move the axel left and right you adjust the upper control arms right? So for instance if the body was leaning pass. side, you would adjust out the pass. UCA and adjust the driver UCA in to make the body lean more to the drivers side.

I am fairly new to this too but didn't know you could do that. I would think an adjustment to the springs would be needed.

If the body is leaning to the pass side....then tell DD to move from the passenger side over to the middle seat...

connordanny wrote:

If the body is leaning to the pass side....then tell DD to move from the passenger side over to the middle seat...

Bill how would you adjust the springs? The reason I think this is because normally the track bar would move the axel right or left. But in the four link it the pressure from one side or the other on the upper link that decides center. so by adjusting the UCA opposit of each other in or out wouldn't you be adjusting the pressure therefore moving center left or right?

The problem I'm having now is that each UCA is mounted the same. Same length and angle from the center of the axel to the frame and the jeep is leaning pass. with little to no pressure on the pass uca. Were as the driver Uca has all the pressure. so i'm guessing to put more pressure on the pass uca I would have to make it longer.

Is your pinion angle correct at this point? If the arms are equal and the pinion angle is correct than the ride height should be the same on both sides. adjusting one out more than the other will immediate change the pinion angle.

I have a really good book called Door Slammers the Chassis book that really helped on my last Chevelle setup. I can get it too you or Summit has it for a few bucks.

Some guys go into great detail setting up anti squat but it really isnt necessary for this sport unless the pinion angles are way off. Its a simple set up for our purposes since we are not really concerned with weight distribution when leaving the line.

I read your post over and over and you seem to have the theory right. Did you try taking the measurement at a different point of the frame to make sure something is not out?

Not an expert.. Just my $.02

cut the brackets off and weld em back on

My though was if the axle is centered on the body and the pinion angle is correct then it has to be an issue with the springs. maybe one is worn? Adjusting one (triangulated)upper control arm in and the other one out will move the axle left or right but shouldn't effect body roll. If the front isn't right it can throw the body to the passenger side as well.

are you saying that one side is higher then the other, or the tire is sticking out further on one side. if it is the second. disconect the uppers. make sure the axle is going to track straight, lowers should be the same. provided your mounts are in the right spot. disconect the uppers, put a jack under pinion to set pinion angle, with the weight of the vehicle on the springs, center jeep over the axle, using a winch, strap or something. then install upper links.

It sounded to me that the axle was centered but the body was leaning to the passenger side.

This is from claytons site:

Set both lower control arms to the same length about, you should be able to put the bolts in both ends with the arms side by side. Might have to make final adjustments can be made later to center the axle if needed.
Put the springs back in and a jack under the pinion to hold the pinion angle. Once you have the pinion angle set where you want it you will have to center the axle under the vehicle. I find a come along works well to pull the body over. Make your measurements from the same reference point on both sides. Install the upper arms on the frame side first. Adjust them to the proper length and put the bolts in on the axle side. Do not worry about them being the same length, just adjust them so the bolts go in on both sides.

how is antisquat related to pinion angle.

Its not is it, just related to control arm angle right? Sure there isn't a spring that isn't seated right or something like that?

rockdw72 wrote:

how is antisquat related to pinion angle.

Never mind I re-read what you where talking about. antisquat % will predict suspension unloading or compressing under acceleration. The unloading or compressing depending on link lengths the pinion angle will change. The only time a drag car will see the loading a unloading of the suspension is when it is affected the AS. An off road vehicle will see the unloading and loading of the suspension all the time, even without acceleration. So while they are related. AS% is not a main concern when dealing with pinion angle in the offroad world, which is what you said.

rockdw72 wrote:

how is antisquat related to pinion angle.

Antisquat is basically loading and unloading of the suspension. Pinion angle is part of it so that there is no bind during loading and unloading. I take back what I said about antisquat not being that important in this sport after reading a few pirate threads. I never thought about the fact of the suspension loading and unloading during climbs. We always concerned ourselves with how much the suspension would load and carry the front end. I guess its just as important here:
http://www.pirate4x4.com/forum/archive/index.php/t-243543.html


There are basic measurements to determine correct pinion and for adjusting a 4 link but I am not sure it will solve his problems if he is stating the links are equal, the pinion is correct and he gets the same measurements on the axle and frame and still has a lean..

Is one spring tight and compressed and the other just sitting there without tension?

looks like we were typing at the same time

I was more concerned about his pinion angle due to the fact he needs to adjust to get ride height equal on both sides. Too much adjustment is going to change the pinion and then during droup it will bind the u joints.


Again, I am not an expert and we would make sure pinion was correct and start adjusting for a/s and see what our 60 foot times were and how it carried the front wheels.. We never had to worry about binding as much as in this sport.


Shoot Mike at Appalachian a email and see what he says...

rockdw72 wrote:

looks like we were typing at the same time

LOL.... on the same track atleast..

sorry I didn't get a chance to respond quicker but work has been crazy due to the rain. But the prob is that the body is not sitting over the axel corectly though the axel is centered and the pinion angle is perfect. I decided to mess with it a bit today before I reponded and here is what i found. When I removed the pass UCA the body centered itself out. then to get the pass UCA in I had to push the body pass side again because the Uca was to long. So what happing was that I had the method to adjust it backwards, which sucks because I can only adjust them out not in. All well I ordered parts to make some new upper control arms. Kind of sucks that they were almost $110 a piece for the parts. At least they will be a little more heavy duty and have more adjustment in them, plus will fit perfect instead of having to use bushings.

Is there enough room to adjust the lowers out in addition to the uppers to get the length right?(adjust them all out about 1/2 inch so the one that is long is about right?)

hmmm thats a good idea.

just make sure the diff will still clear the fuel tank.

Truss wont clear the gas skidplate if I move it back a couple of inches. All well the parts should be here in about a week. After that I should be good to go.

Cool. are you just replacing the one or several? what length? I may be able to use them on the CJ.

just the rear UCA. keep in mind they have the smaller heads on them that use a 3/8" bolt.

ok nevermind.