Caster correction brackets/plates (1 Viewer)

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Jun 20, 2006
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416
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Mission Viejo, CA, USA
 
 
What's the difference between Man-a-Fre brackets and Slee plates (or any others, for that matter), other than price? Ease of installation, advantages/disadvantages, quality, strength, effectiveness, etc...

I'm planning a 3" lift (leaning towards Frankie's right now) and really want to make the best and most complete caster correction the first time around.

I'm sure this has been discussed (to death, some might think), but there about a million posts that mention "caster Correction", and I only had time to look at a few hundred (Okay, I'm exagerating - but not much!). I did a search using "Landtank + Man-a-Fre + caster" and didn't find anything that addressed my question.

Thanks in advance for your help & your patience! I'm continually astounded by the wealth of knowledge so many of you possess, and your willingness to share it with the rest of us.
 
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Landtank's plates rotate the axle around the center, where as Slee's pivot the axle. Both work well and require a DC shaft as they point the pinion at the transfer case. I think Slee's are easier to install.
Man a Fre's drop brackets work to keep the pinion on the same operating angle as stock so the stock shaft remains. Clearly the Man a Fre drop brackets will be the easiest to do. I have Frankie's springs and the LT plates and a DC shaft.... all a lot of $$$ and work, but I'm happy. The LT plates don't seem to align perfectly though for the DC shaft. I'm off by 2 degrees but it's nominal. I think Frankies lift is a little over 3".... to get my pinion pointed up another 2 degrees i need to raise the front a bit with a spacer. LT's plates were not easy to install. You might try Slee's instead as they're designed around a 4" lift. Other's will chime in..... this is just my $.02 and the best of my knowledge.
 
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in my case i'm wondering if just using one OME yellow bushing per side in either in the front or rear of the axle, aligned correctly, would point my axle up a bit.... hmmmm???
in back of the axle would be best as it would create a little more space between the control arm and the tie rod!
some one jump in here!... am i making any sense? (sorry for the hi-jack...just thinking out loud)
 
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AutoCraft Aus

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Between the bay and the Ocean Vic Aus.
 
 
2 degree Super Pro bushes which still flexok and slotthe front holes on the diff 7mm for every degree required [normally 1 deg for true 3" lift] is simplest and looks the most "factory" [7mm = aprox 1/4"]

The axle has no need to "pivot" in its centre axis, as it can move back and forth 1/2" + and cause on issues, we do this often for larger tyres, to clear the rear of the front fenders.

We use machined washers to suit adjust the angle with the slotted holes until correct castor achieved, and then weld the machined washers in place [not fully]

The may require some removal of the cast lump from moulding process on the control arms for the steering arm toward the rear of the front end. [as will any castor correction with correct amount of castor]
 

AutoCraft Aus

Araco Master
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May 21, 2008
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Between the bay and the Ocean Vic Aus.
 
 
in my case i'm wondering if just using one OME yellow bushing per side in either in the front or rear of the axle, aligned correctly, would point my axle up a bit.... hmmmm???
in back of the axle would be best as it would create a little more space between the control arm and the tie rod!
some one jump in here!... am i making any sense? (sorry for the hi-jack...just thinking out loud)
You can use a std bush in rear of diff mount and a half of a 3 deg bush in the front of the diff mount, giving 1.5 deg correction, or more if you slot the hole, and the rear bush being std also keeps the diff higher preventing the steering arm rubbing on the control arms as easily.

A 2 deg bush in the front only will give you 1 deg correction.

Adding kin pin offset bearings can give you up to 1.5 degree correction with std bushes also.

We use these to get neg camber on bigger tyres normally, along with castor correction.
 
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in my case i want to use an offset bushing the opposite of how they were intended to be used.... that is, i want to point the pinion up another 1-2 degrees.

so if i had a set of 3 degree correction bushings and only used one on each side i'd gain 1.5 degrees of pinion angle change, correct?

also wouldn't using the bushings in the rear holes, pointing the pinion up, create more room between the control arm and the tie rod?
 
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Nay

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Aug 17, 2004
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Colorado
 
 
 
His pinion is pointed down below a zero degree operating angle for a DC shaft, which means the full caster correction was too much for the DC. A slight adjustment back up would keep it in spec and aligned for the DC, achieved by using a CC bushing in the opposite direction.

Just a fine tuning adjustment, leaving rubber for the front bushing.
 
Joined
Jun 20, 2006
Messages
416
Location
Mission Viejo, CA, USA
 
 
Landtank's plates rotate the axle around the center, where as Slee's pivot the axle. Both work well and require a DC shaft as they point the pinion at the transfer case. I think Slee's are easier to install.
Man a Fre's drop brackets work to keep the pinion on the same operating angle as stock so the stock shaft remains. Clearly the Man a Fre drop brackets will be the easiest to do. I have Frankie's springs and the LT plates and a DC shaft.... all a lot of $$$ and work, but I'm happy. The LT plates don't seem to align perfectly though for the DC shaft. I'm off by 2 degrees but it's nominal. I think Frankies lift is a little over 3".... to get my pinion pointed up another 2 degrees i need to raise the front a bit with a spacer. LT's plates were not easy to install. You might try Slee's instead as they're designed around a 4" lift. Other's will chime in..... this is just my $.02 and the best of my knowledge.
Thanks for your $.02! The check is in the mail! :) If anyone else would like to chime in on my original question I'd appreciate that, as well.
 

Nay

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How hard to you intend to wheel it? Those drop brackets are an awfully easy mod if clearance isn't a major issue for you.

If you are going F.O.R., that kit comes with LT plates, and of course Slee's kits come with his plates.

The LT plates are an elegant solution, the install is hard work, and it takes time, but you retain as much clearance as possible. Again, usage should determine whether or not this matters to you.
 
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"So how do you then fix the castor?"

i'm not sure..... i've gotten a bit lost btw the pinion angle and caster correction. I always thought the two were not mutually exclusive. but somehow i think i'm not fully understanding this. at this point i just want the pinion pointed at the transfer case and this seems like a good solution considering i've drilled the heck out of my arms doing the LT plates. if somehow i give up a bit of caster and achieve optimal operating angle for a DC shaft that's a small compromise i'm willing to make.

if someone can really break down how caster and pinion angle are mutually exclusive i'd love to hear it.
 
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i like that LT's plates retain the stock axle location fore to aft.... maybe a few different sets to go with variable heights above CC bushings parameters, where plates and a DC shaft are necessary. Do lift, measure hub to fender height and voila! order the perfect plate.
 

Nay

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Aug 17, 2004
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"So how do you then fix the castor?"

i'm not sure..... i've gotten a bit lost btw the pinion angle and caster correction. I always thought the two were not mutually exclusive. but somehow i think i'm not fully understanding this. at this point i just want the pinion pointed at the transfer case and this seems like a good solution considering i've drilled the heck out of my arms doing the LT plates. if somehow i give up a bit of caster and achieve optimal operating angle for a DC shaft that's a small compromise i'm willing to make.

if someone can really break down how caster and pinion angle are mutually exclusive i'd love to hear it.
Caster is determined by the angle of the steering arm on the knuckle - you can roughly measure it straight from the arm if you have a flat surface to measure from and the rig is on a flat surface.

Therefore, caster is fixed to the axle, as is the pinion, and when you rotate the axle for any reason both caster and pinion angle have to change together.

Rotate up by lifting, and you will lose caster. Rotate down with caster correction and you will gain caster but lose alignment of the stock driveshaft u-joint angles.

It is a stroke of pure luck that the stock driveshaft is a "broken back" design, meaning that increasing caster lowers the pinion to align for a DC shaft. In most rigs this is not possible - I spent years trying to deal with caster loss on a stock DC front driveshaft Jeep Cherokee with AWD, and in the end the only solution was a new D44 front angle with axle brackets aligned for the lift I had (same function as cutting and turning the knuckles).

The stock 80 series front driveshaft also seems to defy u-joint physics. It runs relatively clean up to about 5 degrees of variance in t-case to pinion u-joint operating angles, which it simply should not do but yet achieves time and time again. This is because a u-joint operating at a zero degree angle rotates in a perfect circle, but as you add angle the joint moves in an elliptical arc.

If both ends are not moving in the same arc, the entire assembly is forced to rotate out of phase, so when one joint is operating at 11 degrees and the other at 6 degrees, you should always have vibrations. Max tolerance is supposed to be a 3 degree variance between the operating angles of the two ends, but the 80 series front can often go beyond this. Again, nobody here knows why, although I suspect there is something in the overall design that is masking the effects - physically the variances in elliptical angles have to be there, and there going to be impacts of running a driveshaft in a materially different arc on its two ends somewhere in the system (draw a lower arc and higher arc ellipse overlapping and see what you think about that in terms of what the driveshaft is connected to on each end regardless of how much noise it makes).

This is why I personally prefer the DC for the front of an AWD 4x4 running on a decent amount of lift. An 8 degree driveshaft angle split between two joints in the DC (4 degrees each) with zero angle on the pinion end leaves everything operating at maximum life expectancy.

Yes, there is the added complexity of the ball joint and you have to keep up on lubrication, but this is small compared to what I think becomes a frog boiling in water syndrome of misaligned stock shaft. Slowly over time it will get a bit noisier, rumble just a bit, and you won't really notice how hot the water has gotten but it's not nice and cool any more, and you may be shortening bearing life in the t-case and/or pinion if you put a lot of miles on it.

And so I agree. The first measurement in front alignment is pinion angle, and caster follows. Aligning for a DC on a 3.5" lift should give you stock range caster figures. Post up your final numbers if you don't mind.
 
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Rick (LandTank),

I've just ordered the F.O.R. Kit with your plates. I assume everything should work perfectly? Am I correct on this or am I going to need to do some adjustments? I'm also waiting on the DC shaft from Frankie whenever he gets them finished. Am I going to have problems before the shaft arrives?

I apologize if the questions seem stupid. I'm not much of a mechanic but I want to do things right the first time and not have to monkey around with the rig forever.

JPH
 

sleeoffroad

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Caster is determined by the angle of the steering arm on the knuckle - you can roughly measure it straight from the arm if you have a flat surface to measure from and the rig is on a flat surface.
Caster is the angle of the trunion bearings. You are assuming the steering arm is 90 degrees to that. Also measuring it to that is not even close. We verified that when we did the SAS on the 100 and we set the angles of the balls before they were welded in place. We tacked them in place, then had the caster measured. The angle was not even close.
 

landtank

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Groveland MA
 
 
 
Rick (LandTank),

I've just ordered the F.O.R. Kit with your plates. I assume everything should work perfectly? Am I correct on this or am I going to need to do some adjustments? I'm also waiting on the DC shaft from Frankie whenever he gets them finished. Am I going to have problems before the shaft arrives?

I apologize if the questions seem stupid. I'm not much of a mechanic but I want to do things right the first time and not have to monkey around with the rig forever.

JPH

Up until a few days ago I would have said yes. But it seems that Nay and Leroy feel the need to make further adjustments. I'd like to work with them as to why and try and identify if there is something I need to do on my end to correct for this.

Since I can drill my plates anywhere I chose I can customize them for any particular truck. I'd like to avoid this but if that is what it takes then I'm more than happy to work out the details and make it available to everyone.

Nothing agrivates me more than bolting on an item and having trouble with it and I don't want to be someone doing that to others.

Incidentally there will be 4 trucks at my house this weekend with my plates on them. I'm going to remeasure all the pinion angles to get an idea how much they are varying on these trucks. None of these have a vibration problem but that might not be the best acid test.
 
Joined
Jun 20, 2006
Messages
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How hard to you intend to wheel it? Those drop brackets are an awfully easy mod if clearance isn't a major issue for you.

If you are going F.O.R., that kit comes with LT plates, and of course Slee's kits come with his plates.

The LT plates are an elegant solution, the install is hard work, and it takes time, but you retain as much clearance as possible. Again, usage should determine whether or not this matters to you.
Thanks, Nay. My 80 is my DD, so it needs to be freeway friendly. I live in SoCal. Mountains, rocks, sand, and snow are all within at least a few hours drive. Not much mud. I'd like to do "challenging" trails (Rubicon and maybe Dusy-Ersheim someday), but I don't want to beat it up (no Hammers for me!). My local club is mostly built 40's - though wagons are increasing - and I'd like to do most of the runs they do. I'm willing to go slow, choose my lines carefully, and take good spotting advice. With all that said, I've accepted that about 3" is the maximum lift I should prudently do.

Do you (or anyone else) know how much clearance the drop brackets will actually cost me? Do they become the lowest point on the truck? Maybe a dumb question, but do the brackets raise as the tires climb over obstacles? Or, is it likely that the brackets will hang up on the obstacle after the tires clear it?

Also, if anyone actually using the drop brackets can answer these questions, I appreciate that.

Thanks!
 

Nay

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Caster is the angle of the trunion bearings. You are assuming the steering arm is 90 degrees to that. Also measuring it to that is not even close. We verified that when we did the SAS on the 100 and we set the angles of the balls before they were welded in place. We tacked them in place, then had the caster measured. The angle was not even close.
I stand corrected.
 

Nay

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I'd like to do "challenging" trails (Rubicon and maybe Dusy-Ersheim someday), but I don't want to beat it up (no Hammers for me!).
Don't do any type of drop bracket, take it off your list. An 80 with a 3"-4" lift with 35's has enough low hanging bits, you don't want to add more for rock crawling.

I would do plates, because I bet with the trails you looking at you'll want to be a bit closer to 4" of lift than 3", it makes a real difference in the big rock in an 80.

I wouldn't go higher, that's when you start talking about 37's on that 3.5" lift if you want more (and you start talking about busting stuff, too :D).
 

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