Setting caster on a Toyota front axle

[squirrel]

I'm working on a coil conversion for an '84 Toyota pickup, and I'm going to weld brackets to the axle housing to mount radius arms. How I position the brackets will determine the caster, which I have a spec for in my service manual (2.25+-1 degree). However, it's difficult to measure the caster from the kingpin races directly. Does anyone know the angle in stock configuration for either the spring perch or the pinion, which are easy to measure? By locating off of those faces, I should be able to keep the caster fixed. Or are there other ideas on setting caster properly?

[79coyotefrg]

why not  run a 4 link,  welding the brackets will be the same but  you wont have to worry about the castor, 

if this is a offroad only rig??    then just get it close  and go

[RAZOR]

Its pretty hard to set without the right machine/computer. But Measure it out as close as you can so that both tires are forward the same amount. Then test drive it and it it pulls to the left, then your Left tire is behind your Right tire. And if your truck pulls to the right, Then your Right tire is behind your left tire.

[ZukIzzy]

It is easy to get it pretty close using a magnetic angle finder. I disassemble the axle  down to the housing. then use a magnetic angle finder on top of the king pin bearing race. if there is no damage to the axle (bent warped or bad kingpin race) the race will be perpendicular to the caster. SO if your frame were level or at ride height and you set the kingpin race perfectly level you will in effect have 0* Castor at ride height. You want some positive Castor so rotate the top kingpin toward the back of the rig till the angle finder reads 2.5 to 3* and weld it up. I use 2 angle finders 1 on each side to check that they are the same. if they are not there is little you can do save cut and turn the knuckles to match. I have run rigs with up to 1.5* difference side to side and not been able to tell. but they were big tired trail rigs that saw little street time. It is good to have some adjustability in your links to make up for sagging springs or more weight than was anticipated or maybe more spring rate for more lift for those new bigger tires next year.

hope this helps.

Wayne

[squirrel]

Thanks for the tip Wayne - using the angle finder on the top kingpin race works nicely. This truck is for freeway use so I do want to get it accurate.