Castor Correction Opinions/Confusion (1 Viewer)

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fzj80kidpen

fzj80kidpen

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Nov 8, 2004
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After reading about all the different castor readings people have gotten with varying lifts I decided to go ahead and have mine checked before swapping the OME CC bushing I have.
I have the OME heavy upfront and mediums in the rear.
Stock front bumper will soon be replaced with custom and winch (within a year)
I hung my 185lbs on the front and it did not appear to change the castor at all.
Castor readings are DS -1.15 PS -1.35
My understanding is that I need to get back to stock Castor of +3.0 and the OME CC bushings only correct +2.
So what should I do:
1. just go head and do the OME CC and be happy or not at +1.0
2. Get slees CC bushings and be happy or not at +2.0
3. Get slee plates and be happy or not at +3.0

I am leaning towards the plates now.
Advice and opinions appreciated.
Bill
 
They are for a 6" lift. I have 3" and they about $600 more. Ouch.
If money were not object then I would do portal like you have with the 4" :)
Or even better just use the tank
 
landtank,
My front pinion is definitely pointed above my trans now. I am getting GRR on deceleration that has me motivated to correct this. How do I take front U-joint measurement?
Angle of the flange minus the angle of the driveshaft?
I searched an saw that with 4" you had to rotate the axle 7* and you mentioned to adjust the panhard prior to measuring. Can you explain this?

bill
 
Last edited:
landtank said:
before you make a decision you should read the drive angle of your front u-Joint. This is easily done and could shed some light on the possible vib problem some when correcting for that much caster.
Click to expand...

Good point.
 
fzj80kidpen said:
So what should I do:
1. just go head and do the OME CC and be happy or not at +1.0
2. Get slees CC bushings and be happy or not at +2.0
3. Get slee plates and be happy or not at +3.0

I am leaning towards the plates now.
Advice and opinions appreciated.
Bill
Click to expand...

How about the MAF 3" drop brackets?
 
You got to love search.
Found this and it answers some of my questions.

mabrodis said:
The better way to center the axle would be to drop down the frame mount for the trackbar to the bar is level again, when it's level it gives the most movement up and down with the littlest side-to-side movement. Most liftkits for 4Runners have a rear trackbar drop-down piece, surprised no-one has made one for the Cruiser, granted it'd need to be a bit bigger and beefier, etc, but certainly do-able.

As far as adjusting, when I did my 80 just measure from the frame to the inside of the tires, I was only adjusting the rear trackbar, so just kept adjusting it till it's about the same measurement on both sides. Catch there is for it to be centered while wheeling you need all the crap in there that you have while wheeling, since what you're measuring changes with ride-height.

This is what I did on my '97:

http://www.colorado4x4.net/tech/rear_trackbar_lengthen/trackbar.html

Good Luck...
Click to expand...
 
That post is about an adjustable rear panhard rod. I thought you were trying to correct your caster angle.
 
What I like to do for measuring the front drive angle is this:

Jack the front of the truck up so the axle is on jack stands with the wheels off the ground and the weight of the truck is on the axle.

Place the transfer case in nuetral so you can rotate the front driveshaft.

Now rotate the drive shaft so that one of the u-joint cups is facing straight down.

Using a protractor that I got at Sears take take a reading on that cup. What I do is place a socket on the cup as an extension and then hold the protractor against it. On this first reading I move the point to where the needle is pointing.

I then rotate the drive shaft 90* and place the socket and protractor against that cup and count the number of degrees between the needle and the marker form the other cup.

This will give you that u-joints drive angle.

You could do the same for the rear as well and then factor in how much caster you need to see where you need to go.

This is the protractor I used.
 
Thanks Landtank,
Just got back from Sears where I bought that very protractor.
You method is more detailed than what I was thinking.
I'll use it this evening and post up what I find.

Ivan80 - I was searching around and ran across the thread where lanktank mentioned adjust the panhard first. Same principle as rear trackbar in my mind.
 
The thing that is hard to grasp with the bushings and Slee's plate is that the arms are not static.

While all three will change the axles position in relation to the arms it's the axle that never really changes in relation to the frame.

This is easier to visualize with Slee's plate. His plate rotates on the rear bushing bolt. Think of that as the pivot point in a pair of scissors.

So looking from the side of the axle, as you rotate the axle the rear bushing drops as the front bushing is raised as it's actually rotating on the tires.

This condition moves the arm down and away from the axle. This movement actually subtracts some of the effect of the plates. I think it's this effect that makes things un-predictable.

I've been trying to get a hold of a pair of OME bushings because I can make up a template that will accurately and consistently provide a given amount of correction. This would be done by pressing them in a way as to rotate the axle on it's center rather than tilting it at the bushings.

I don't know how much correction this would yield but a good rule of thumb is for every 1/8" of offset in the bushing's center you get 1* of rotation. If someone has a set of bushing hanging around and can measure that offset it might help give me an idea of what the out come would be.
 
I'm your man... I have two sets of the 2 degree OME bushings, (one installed, other in box) and a set of Slee's 3 degree that are just about to go in. More than happy to send you one, but I'll need it back eventually. Send me your address via PM and it will be shipped sometime this week.

Fernando

landtank said:
If someone has a set of bushing hanging around and can measure that offset it might help give me an idea of what the out come would be.
Click to expand...
 
I have a set of OME CC bushings sitting in the back seat.
Here we go OMECA77B - CC Bushings
With rule lined up with the center line.
60mm diameter therefore center is 30mm
Hole is 15 mm wide
placement measured across center line is 17 - 32 mm
Center of hole is 24.5 mm
Offset from center is 5.5 mm per CC bushing
Using 25mm per inche thats just under a 1/4" (.22)
Which puts the OME just under 2 * as they say
 
Last edited:
XXXR said:
Same issue with my 2.5 lift and the OME bushings. Still reading low even after 2 attempts. I've decided to try the 3 degree bushings from Christo. I have not had the time for the switch yet, but I'll let you know how it goes. "Factory" is between 2-4 degrees.
Click to expand...

That's where i was. Went with stock bushings and slee's plates. Got the vibbbbbs with or without a DC shaft :crybaby: :confused:
 
So if I am understanding this mind teaser the optimal thing to do would be to design some plates that have two holes 7.3" apart on center with each hole 1/2 offset rather than a 1/4" offset to provide a CC of 4* rather than 2*.
On the vertical axis.
Is this your thinking Rick?
Or are you suggesting moving both holes forward as well?
 
Sorry to jump in here guys, I installed an Old Man Emu 2.5 lift kit 4 years ago and went on the advise of an other 80 owner to leave the original casters in place as they were fine. Now i'm a little worried after reading this and other posts. If someone would jump in and tell me if i may have damaged anything. Ashamed to say that my rig has never been off-road. :eek: Thanks
 
fzj80kidpen said:
So if I am understanding this mind teaser the optimal thing to do would be to design some plates that have two holes 7.3" apart on center with each hole 1/2 offset rather than a 1/4" offset to provide a CC of 4* rather than 2*.
On the vertical axis.
Is this your thinking Rick?
Or are you suggesting moving both holes forward as well?
Click to expand...

You can read up on a thread titled "a different caster plate". It was how I solved this problem. Beware that it goes through the how design and thought process so it tends to be a little varying in details but you should get the jest of it.


My thinking is trying to give people a way to measure and get predictable results as until now it's been a little hit and miss and a PITA for some.
 
felt, i'm sure nothing is damaged. I honestly am kinda stuck right now on what "I" should do. Biggest issue with castor and the 80 series land cruiser is getting enough caster once lifted so the rig tracks straight and fight getting driveshaft vibrations.
 
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