Setup:
Hello all I have a new-to-me '88 Samurai Tin Top with a homebrew SPOA with stock springs + add-a-leaf. The ride is unbearable, I took the add-a-leaf out and no really change in ride, crappy shocks off a Astro-Van is what previous owner told me. Anyways after a ton of research surfing web, and a really informative call to Dan at LowRangeOffroad.com helped me figure out that what I want is SPUA with OME Dakar springs and a TT Rears-Up-Front Kit to get to my goals of on road comfort and stock reliability with only very occasional offroad/trail riding use.

Issues:
Previous owner hacked off stock perches and welded them back on the top. Given how hackishness(<not a word) everything looks I don't know I trust the positioning of the spring perches currently to use them as a guide to weld the new ones on. I have read until my eye's hurt and I either am to dense to get it or there is not enough visual aids for me understand Won' the TT RUF kit set the correct castor? Am I correct in that it positions axles using the spring perch pin/bolt (The one goes through the springs and seats in the hole in the spring perch)? I have taken a couple of days and I can't find a single 4x4 shop in Asheville or surrounding areas so I can't even find anyone to pay who I would trust to do it right.

I understand you use angle finder to determine pinion angle but, unless I am visualizing it wrong, don't you have to have the correct springs mounted with load on the axle to determine that angle? If you do it while your suspension is unloaded when you compress it for your normal load the angle will change correct?

Is there any kind of guide/how-to with lots of pictures to determine proper/stock pinion angle? I've read most all  of Ack's driveline faq's and I have read countless posts but still am having problems wrapping my brain around this.

Any help or suggestions would be greatly appreciated!

Media:
Overview

Shaky cam explaining problem

Wheel off and steering sway bar overview

What psi are u running in ur tires?

In what ways are ur sammi driving/riding horrible?

Google "how to measure and set pinion angle".....there r tons of descriptive articles that will help. Words alone kinda lack...but u want a -1 thru -3 degre difference in pinion angle and output flange angle. U may read about parallel or pointing at....but in ur case u want the -1 thru -3.

Weld the perches once it's all bolted up and u have the pinion angle set...tack it then and then give it a good bead.

Returning back to "factory configs" will get u back to the correct castor....but not sure if castor has a correct or incorrect...a modification has pros and cons and has other effects...such as affecting castor...but if u want lift then something has to give!...skyhiranger has a spua with the rtf...he will know a lot more.

On the front axle, Pinion angle and Caster are directly related!  The correct way to set up an unmodified (the hub castings have not been "rotated" on the axle housing) is to place an angle finder on the top of one of the the kingpin capping plates, then rotating the axle to the factory angle before welding the perches in place.  with this done, the pinion angle should be correct (or at least acceptable).

Regarding Pinion angle:  Unless you are using some form of CV driveshaft - like the ones on n '80s Toyota pickup truck - the face of the pinion flange must be parallal to the face of the transfer case flange for the driveshaft to transfer rotational energy efficiently.

See:
http://www.4x4wire.com/toyota/tech/driveline/

and

http://www.4xshaft.com/driveline101.html

(found at Ack's FAQ by searching for driveshaft)  for details.

I hope that this helps!