3-link for fzj80

[mxtaco48]

I had a few questions. (I am actually buying the custom made lift which ben at slee had made. ) Sorry for so many questions but havent found the answers in my searches.

Actionjackson was gonna use a 3-link to correct for caster....how does a 3link correct caster?

The heim Joints are adjustable...is that the way the caster is corrected? and if not how do most people correct caster on a 3 link?

I will be using 6-8" lift springs. Stock location for lower control arms. Custom control arms that use the stock locations. What angle does the panhard need to sit at? it seems on a lot of 3-linked that the arm is level under full compression on that side. Also due to this it would seem better to keep the panhard tower on the axle fairly short and drop the bracket that attaches it to the truck? Please correct me if I'm wrong.

Additional question-do yall have to lengthen the stock rear driveshaft or is it fine with this much lift without slipping out?

I plan on using the adjustment sold by slee to lengthen my tie rods. and 14"-15" shocks. Extending brake lines. DC shaft.

 

[mxtaco48]

I am a newbie to linked suspension and correcting for caster. Trying to gather plenty of info prior to install.

 

[Isotel]

Did you read thru this - http://www.actionjackson.com/cruiser/mods/20060110.asp

3-link corrects your caster because you are able to Fab everything yourself and put your caster where ever you want, (the Stock control arms wont let you do this)

I would not re use the stock control arms in any way..

Track Bar should be Parallel with the ground at Ride height..

steering should be beefed up with Heavy wall DOM Treaded for your Tie rod ends..

 

[mxtaco48]

Did you read thru this - http://www.actionjackson.com/cruiser/mods/20060110.asp

3-link corrects your caster because you are able to Fab everything yourself and put your caster where ever you want, (the Stock control arms wont let you do this)

I would not re use the stock control arms in any way..

Track Bar should be Parallel with the ground at Ride height..

steering should be beefed up with Heavy wall DOM Treaded for your Tie rod ends..

Yeah I read through it and that article is more or less where my questions arose from. I do not plan on using any of the stock components on the suspension. Ben at Slee had built a custom 3 link that I plan on using some components off of if I can. I'm posting on the boards kinda to figure out if I can and to answer a few other questions.

 

[Jeromy]

I would make the panhard bar close to the same angle as the drag link and pivot in roughly the same plane to avoid bump-steer.

 

[mxtaco48]

I would make the panhard bar close to the same angle as the drag link and pivot in roughly the same plane to avoid bump-steer.

Am I missing what a panhard bar is?? I believed the panhard bar was the rod that will connect at the top of my axle to the frame.

The drag link goes from PS to DS on axle making it perpindicular to the panhard. Maybe I'm wrong but what I am defining as these are confusing me as to your suggestion. Thanks for any clarifications.

 

[ats4x4dotcom]

I would use standard bushes, and put swivels in the arms, it it were me, still flexes the same, wear and NVH arent amplified.

 

[Jeromy]

Pan hard or Track bar......on an 80 at least runs from the DS frame rail to the PS of the axle.
Drag link....conects the steering arm to the knuckle.
you want these two to be close to the same length and mount in about the same locations so that when the passenger side of the axle moves up and down it moves in the same arc as the Drag link (steering).
These keeps the steering wheel from turning in your hand as the axle moves up and down.

 

[mxtaco48]

I see what you mean now....i dug a lil deeper for some more pics and get the idea.


whats NVH stand for?

 

[mxtaco48]

You say you want these "close". I"m a pretty OCD kinda person. So, when you say "close", how exact do I want the geometry to be? Is it an eyeball it kinda thing or is there a formulation for it. I've seen the calculators on pirate4x4.com but I feel like a need a better understanding of the project first.

 

[jon@svwbarchitects.c]

It can be a eye ball kind of thing. The closer the angle the better as it helps with bump steer.

 

[mxtaco48]

OK, and how about the 3rd top link? I will follow the actions of others and add a bracket on top of the diff and an attachment back to the frame. How do I figure out where the locations need to be? just square it to the frame once I decide where on the axle I want it and make sure it is parallel to the ground? Of course making sure the tower isnt too tall as to hit anything.

 

[alkaline747trio]

The 3rd link is just called the 3rd, upper, or top link. You want it to be parallel to the lowers with as much vertical separation as you can get without interference, and you want all the links to be the same length.

It's unlikely that you will get your links parallel to the ground, either your links will be crazy long, or you wont get proper separation, or your brackets will hang down too low, or they will contact the frame or other stuff when you start articulating.

 

[mxtaco48]

The 3rd link is just called the 3rd, upper, or top link. You want it to be parallel to the lowers with as much vertical separation as you can get without interference, and you want all the links to be the same length.

It's unlikely that you will get your links parallel to the ground, either your links will be crazy long, or you wont get proper separation, or your brackets will hang down too low, or they will contact the frame or other stuff when you start articulating.

Great thanks. This thread has helped me understand 3 links much better

 

[clownmidget]

https://forum.ih8mud.com/showthread.php?t=119989

go to post #51, that's where I documented a bit with some pics. you'll be very constrained for locations of the mounts on the axle if you retain the stock spring perches, stock shock mount location, etc. as well as where the tower will fit (both on the axle and then where it fits up into the engine, engine mount, frame rail, etc).

 

[mxtaco48]

https://forum.ih8mud.com/showthread.php?t=119989

go to post #51, that's where I documented a bit with some pics. you'll be very constrained for locations of the mounts on the axle if you retain the stock spring perches, stock shock mount location, etc. as well as where the tower will fit (both on the axle and then where it fits up into the engine, engine mount, frame rail, etc).

What would you suggest doing? I checked out your pics....did u move the buckets forward? and if I keep the tower lower couldnt I reduce the risk of hittin the engine?

 

[clownmidget]

What would you suggest doing? I checked out your pics....did u move the buckets forward? and if I keep the tower lower couldnt I reduce the risk of hittin the engine?

use the link calculator found on Pirate and other boards. play around with that first before making any hard decisions. I didn't touch the spring buckets or relocate the shock mounts, just lowered the bottom shock mount and converted it to an eye style mount.

once you see where the axle mounts can go with the interference of the front drive shaft and tie rod you'll see that there is just barely enough room on the short side of the axle for the mount to fit while clearing the e-locker assembly on the diff side and the spring perch, shock mount, etc on the knuckle side. there's not a lot of up and down adjustment space either due to the tie rod and drive shaft. with the lower link axle mounts constrained like that, you end up playing around with the upper link location/position. I don't recall exactly how high the axle tower can be and still clear the motor mount (in the rear), the coolant elbow (in the front), the engine-a/c compressor (inboard side), and frame rail (outboard side) but somewhere in the range of 6-8" so that your total spread between the axle mounting points of the lower links and the upper link is 10-12".

On the frame end of the upper link you'll be constrained there as well due to what the upper link will come in contact with when that side is stuffed up in there. Also, the frame is bending up from the mounting point of the lower link and curving inward making the frame rails rise and narrow. ideal placement of that mount will depend greatly on what happened at the tower on the axle BUT where it ends up might be a bit off of what was ideal. You can also just have a series of mount holes on the tower of the axle mount that will let you raise or lower it an inch or two.

My biggest change relative to what Shawn Jackson and Simon Morris did was to move the frame mounting points of the lower links back to be integrated with the tranny cross-member. That was based on wanting to run arms that were a bit longer and as close to horizontal as possible (34" eye-to-eye) with the amount of suspension lift I have. Personally, I like it too since there is minimal welding to the frame rails and the lower link mounts can be modified, etc on a work bench by unbolting the whole cross-member assembly. Good luck

 

[mxtaco48]

once you see where the axle mounts can go with the interference of the front drive shaft and tie rod you'll see that there is just barely enough room on the short side of the axle for the mount to fit while clearing the e-locker assembly on the diff side and the spring perch, shock mount, etc on the knuckle side. there's not a lot of up and down adjustment space either due to the tie rod and drive shaft. with the lower link axle mounts constrained like that, you end up playing around with the upper link location/position. I don't recall exactly how high the axle tower can be and still clear the motor mount (in the rear), the coolant elbow (in the front), the engine-a/c compressor (inboard side), and frame rail (outboard side) but somewhere in the range of 6-8" so that your total spread between the axle mounting points of the lower links and the upper link is 10-12".

QUOTE]

I will be using stock locations for the lower links with custom control arms. I will be eliminating the upper control arms and using the single upper link. I thik I will not run into the problem of the axle mounts being constrained like you had. What do you mean by total spread of the links?

 

[Francesco_from_Italy]

Hi, I'm going to do the same work you're talking about on my FJ 40 with 80 axles (I made a system with 4link in the rear and panhard and radius arms in the front, but the front axle can't almost move; see all here: https://forum.ih8mud.com/showthread.php?t=112804
I've got some questions...

First of all, what most worries me is the strenght of the 3rd link: I'll use uniball M30 (30 mm wide, a little less than 1,25") like this:

and a tube a little wider (about 45 mm); considering that all the rotation power of the axle will lie heavy on it...well, I hope it will be strong enought, what do you say?

Another question: they suggested me to build a 3rd link long 80% of the lower arms (the lowers are about 70 cm/28" long so the 3rd would be 56 cm/22"); I read that here someone suggested to make all the arms of the same lentgh...who's right??

Last thing: is so important to calculate the squat or I can just approximate?

Francesco

 

[Francesco_from_Italy]

Ooooooooops, I forgot a thing: I would keep standard rubber bushes on the lower arms, do you think they would work as well as if I use uniball or johnny joints (consider that overthere in italy johnny joints are almost unknown and would be difficult and expensive to find them)?

Francesco