Isn't This the Easiest Caster Correction?

[Nay]

For those who have access to a fabrication shop, which I do, this would seem to be the easiest and most cost effective caster correction:

First, drive truck to fab shop and walk Starbucks and read a book while the shop does the following:

1) Remove arms and press in new factory rubber bushings
2) Cut off the rear axle arm mounts on the front axle
3) Reinstall the arms at front axle mount and frame mount
4) Rotate the pinion down (only one axle mount remains so pinion will rotate freely) so that u-joints are in a normal offset position (not the stock "broken back" alignment), increasing caster along the lines of using the Slee arms on a 4" lift
5) With new pinion angle set, weld on new heavy duty rear mounts (still talking rear mounts on the front axle) one side at a time, drilling the bolt hole per the new pinion alignment (do one side of each mount at a time for proper bolt alignment using bushing sleeve as drill guide)
6) Repeat the mount fabrication on the second side.

I doubt that would be more than two hours of labor and a little bit of metal stock and welding, and you could set the pinion exactly plus gain a heavy duty front mount. No guesswork involved, much like rotating the knuckles. What am I missing?

Nay

 

[-Spike-]

I don't know a lot about welding, but there's probably some issues welding to the (cast? Forged?) arms. I know there's issues with one or the other, don't remember which, or which the arms are.

Yes, it sounds easy. Another thought might be some sort of fabricated mount that through-bolts to the stock arms. Dunno the cons to that either.

-Spike

 

[Tools R Us]

The old school "fix" was the washer mod, Rick evolved it with his plates.

http://www.safari4x4.com.au/80scool/tech/caster_mods.html

 

[FJBen]

Are you going to run into clearace issue when rotating that axle down? Doesn't seem like a whole lot of room between the arm and the bottom of the axle. The passenger side is already cut/carved out from the factory...

I don't know, just thinking outloud

 

[landtank]

I designed a plate that interlocked into the axle bracket through the bolt holes. Once you determined how much correction you needed, you would simply pilot drill new holes in the plates that would rotate the axle on it's center to the new position.

Then simply bolt the plates up to the axle and drill out the new holes through both the plates and the brackets and then bolt up the arms.

There is a long and contorted thread out there following the design and execution but probably more confusing than anything. I'd post some pics here but the file upload feature isn't working currently.

 

[OGBeno]

The old school "fix" was the washer mod, Rick evolved it with his plates.

http://www.safari4x4.com.au/80scool/tech/caster_mods.html

Those Oz folks are pretty smart when it comes to this stuff.

That modification looks like it would take 20 minutes!

I keep having to remind myself to always go back to the LCOOL page for simple answers to simple problems.

Thanks Kevin for the reminder.
-o-

 

[FJBen]

Am I reading this wrong? I thought he was asking about changing the "rear" mount...on the axle...

 

[Nay]

Am I reading this wrong? I thought he was asking about changing the "rear" mount...on the axle...

You are right. If you cut off the rear mount on the front axle, the axle will rotate freely. But as you point out, that will pull the forward mount upwards and possibly cause a clearance issue with the arm to the tube as you are raising the front mount.

So maybe I have it backwards. Leave the rear facing mounts alone because rotation of the pinion down will drop that mount and lower the arm slightly. So pull and cut the front mounts to do the rotation, and then fab new heavy duty forward mounts with a slider feature for the new forward mount bolt hole location once you've completed the rotation. No issues there with clearance for certain.

Whaddya think? That gets you your pinion rotation (caster correction) and takes care of potential mount stress problems while possibly creating a heavy duty slider surface on the front mount.

Edit: the old school trick looks like the easiest solution and does exactly what I am talking about. Problem is when you run out of adjustment on that stock mount. I'm just talking about replacing that section of the mount with a new piece that drops the hole lower and beefs up the mount. Same basic premise. Just seems awfully easy compared to all the other expense and gyrations you can go through to deal with this issue.

Nay

 

[alkaline747trio]

That does work up till about 3", after that arms would be better unless you plan to use a CV-shaft. New arms which also move the axle forward are better for 36"+ tires in how they keep the tire away from the harder to trim rear of the fender.

 

[-Spike-]

Ah, I read it wrong. I thought he was talking about cutting and welding the arms themselves, at or near the rear FRAME mount.

-Spike

 

[Rich]

...4) Rotate the pinion down (only one axle mount remains so pinion will rotate freely) so that u-joints are in a normal offset position (not the stock "broken back" alignment), increasing caster along the lines of using the Slee arms on a 4" lift...

Have you already worked out the geometry? I'd hazard a guess that much axle rotation will result in too much caster. I'd reckon after you set the pinion angle where you have described, you would then need to cut and turn the knuckles to get the caster correct. And then you would need to modify the steering arms to eliminate the steering linkage interfering with the radius arms.

 

[Taz]

why not just install the slee castor plates and call it good? you can go back to stock if you ever want to make a change (speaking from experience).

 

[kennyv0826]

I am slightly confused, maybe because I've had a long day and am on my second Jack and Coke (double). I am planning on lifting my 80 5-6 inches and running 37's. Am I going to need to cut and turn the front axle or can I get away with something less involved. I am aware that I will most likely need to do some fender trimming which dosent concern me but I do want my Cruiser to to drive down the road straight and keep my alignment specs as close to factory as possible.

Oh, and I want to have better than average front flex since I know that 80's are notorious for having the front unload way before the rear causing undesirable issues off road. Is Slee coming out with new front arms? If so, what differences will there be and are there any weaknesses that need to be adressed?

Lots of questions I know, but any help would be great!

 

[FJBen]

I am slightly confused, maybe because I've had a long day and am on my second Jack and Coke (double). I am planning on lifting my 80 5-6 inches and running 37's. Am I going to need to cut and turn the front axle or can I get away with something less involved. I am aware that I will most likely need to do some fender trimming which dosent concern me but I do want my Cruiser to to drive down the road straight and keep my alignment specs as close to factory as possible.

Oh, and I want to have better than average front flex since I know that 80's are notorious for having the front unload way before the rear causing undesirable issues off road. Is Slee coming out with new front arms? If so, what differences will there be and are there any weaknesses that need to be adressed?

Lots of questions I know, but any help would be great!

START SEARCHING! lots of threads to read on this.

For that much correction you are custom arms or cut & turn. As for getting more than average flex....search is again you friend search "RTI" and you'll see how I've gotten more flex.

And for the unloading, I don't know that I'd say the 80 is notorious for this? Maybe the front dictates lean more, but as for the unloading I haven't dealt with it.

 

[Nay]

And for the unloading, I don't know that I'd say the 80 is notorious for this? Maybe the front dictates lean more, but as for the unloading I haven't dealt with it.

"Unloading" is a common issue with radius arms on steep climbs. In my own experience, there is a greater issue with radius arms on taller lifts. That's why the hardcore crowd typcially will adopt a limiting strap to the center of the axle so that both sides can flex, but the entire axle cannot drop out and "unload" effectively putting the entire traction requirement to the rear.

As for the 80 on a 3" lift, I haven't felt it one bit, but you go up to 6" and engineer a longer travel radius arm suspension, and I imagine it could be a problem.

Nay

 

[Nay]

why not just install the slee castor plates and call it good? you can go back to stock if you ever want to make a change (speaking from experience).

Caster plates are a single set alignment to rotate the pinion for a DC shaft on a 4" lift. I don't have a 4" lift and I don't want to use a DC shaft because I don't have vibrations. Caster plates on my lift would likely put me in a now man's land where both a DC shaft and the stock shaft would vibrate.

Nay

 

[Nay]

Have you already worked out the geometry? I'd hazard a guess that much axle rotation will result in too much caster. I'd reckon after you set the pinion angle where you have described, you would then need to cut and turn the knuckles to get the caster correct. And then you would need to modify the steering arms to eliminate the steering linkage interfering with the radius arms.

I am measuring the pinion/t-case/driveshaft angles today. But I don't think it will be too much, because people are running the Slee 6" arms on the 4" lift with stock driveshaft to great sucess. Since the 6" arms correct something like 11 degrees of caster to use a DC shaft on the 6" lift, use with the stock driveshaft on a 4" lift means you have corrected past the DC shaft angle to a standard offset u-joint angle. In other words, exactly what I am talking about here, but that costs $700 for the arms.

I have about an inch less lift than the Slee 4", so I need less correction. If it works on the 4", it should work perfectly on my setup, but instead of buying $700 arms I can have tabs ("washers") welded onto the stock brackets to create a new mount for the rotated pinion.

I am definitely going to do this unless my u-joint angle measurements tell me otherwise. With OME correction bushings my caster is under a degree, so I'm probably minus 2 or so with stock bushings. Anywhere between 6 to 8 degrees of correction should be excellent. I'll report back.

Nay

 

[sleeoffroad]

Caster plates are a single set alignment to rotate the pinion for a DC shaft on a 4" lift.

Actuall not, caster plates are designed to put the caster back to spec for a 4" lift. We did not design it with pinion angle in mind. It works out that a DC shaft works in most cases for this setup.

The problem with what you are proposing is exactly the same as the caster plates, the tie rod will come into contact with the control arm if you set it to far. If you have the capability to cut the mount, I think the washer method is way easier.

 

[Ivan80]

Has anybody ever considered using a 5* bushing in the front hole, and OME in the back to give just a little extra correction?

Maybe I'm being too elementary about this, but it seems one OME would give 1.5*, and one 5 degree would give 2.5* for a little less than 4* correction (the bushings would need to be slightly turned so the bolt spacing would line up). Would that be any sort of solution for the guy who needs just a little more correction without getting into that grey area of needing a DC driveshaft.

Those 5* bushings may limit flex too much for the Crawlers out there, but it may work for the DD and expedition types...?

I'd be in for half on a set of those 5 degrees if anybody wants to try it

 

[landtank]

The upload is working so here are some pics of what I did.

The first is to show how the plates are drilled.

The second shows a plate completely drilled.

And the last is the completed job.

While only the front hole is shown the rear holes get drilled as well.

On my truck with the Slee 4" springs and heavily armored I was able to rotate the axle 7* to align for a DC Shaft and get Caster to be almost ideal.

One of the benefits is that you can select the amount of correction you induce and because you are rotating the axle on it's center you can get more correction before the tierod hits the arm.

I have another 2 sets of brackets as well as the cad drawings if anyone wants them.