Hey guys. I have been researching till my eyes hurt and have come up with mixed answers so I wanted to see what you guys thought.

I just finished doing rears up front on my 1980 pickup. I used my 80 main leaf so the spring center is 1.375" forward from the stock front springs from what I have read. The srings are hung with a TG hanger and TG 5.5" shackles.

My question is this: since the axle is moved farther "up" on the springs the axle is rotated down. I am not as worried about my pinion angle from this as I am my caster. I have read that factory caster angle is about 1.5* negative, or rotated back. If this is the case then mine is now a larger degree negative correct? So, is it bad to run too much negative caster?? I have researched people running as much as 10-12* negative and others who say no more than 6* negative. What do you guys think?

This is not a daily driver. As a matter of fact if it is more than 30 miles it gets trailered so maybe this is not as big of an issue for me as for others but want to know if it is in fact an issue. Thanks for the help.

 

If your springs are relatively flat you shouldn't need a shim. If you have a lot of lift you may want to run a shim. I have 4 inches of suspension lift a drop hanger and 5.5 shackles and I do not need to run a shim. Some people use the front stock spring hangers and a 5.5 shackle which makes the caster worse.

 

Not that big a deal from what I can tell and the change is in the good direction:
- http://www.4crawler.com/4x4/ForSale/Shims.shtml#FAQ1

And factory caster angle is positive:
- http://www.4crawler.com/4x4/4R_TechInfo.shtml#Steering

And your shackles are adding about 2 degrees of caster angle:
- http://www.4crawler.com/4x4/ForSale/...es.shtml#FAQ12

 

Ok sounds like it may not be that big of a deal then. I dont know why there is so much lift from these springs. At first I made the packs with the top 3 leaves out of my 80 then the top 3 leaves cut down out of an 87 4 runner pack. With the six leaves, the drop hanger, and the longer shackles it lifted the front about 5-6 inches.....every bit of 3-4 inches higher than the rear which has 63 chevy's on it. I pulled 2 leaves out of each side and it made it more level so now I only have the first 3 leaves from my 80 and the main leaf cut down from the 87 pack. It seems to be holding the wieght of the motor fine and there is still a good amount of arch in them. I also forgot to mention I moved the front hanger roughly 3/4 of an inch forward as well if that changes anything.

So to answer your statement whokrz, the springs are really not all that flat. Definately much more arched than I would have expected from aa 4 leaf pack with the added weight of the motor.

Roger:
I have read your website extensively to try to get some insight on this issue. I am glad you chimed in. So the factory caster angle is 2* positive for a truck?? So did I make the angle more positive or take it into the negative?? I have read that the desired angle is about 6* positive (axle tilted down??) so if I get an angle finder is that the angle I should be shooting for? I have also read that you can redrill the shackles to 4.5" eye to eye to help with the pinion angle and caster angle if need be but then I think I would have to move the hanger back to the stock location to get the shackle angle where it needs to be. I am kind of reluctant to do this because I like the extra inch or so forward the hanger moves the axle, this should help my pinion angle as well (though not by much but every little bit helps).

Thanks for all the help guys.

 

Sounds like you have some lift springs in there then, I have 3 - '83 p/u and 3 - '85 4Runner leaves (all stock) and basically flat springs:


But on the caster angle, the 6* figure is what the spring perch should be at for a close to stock caster angle. Longer shackles increase caster angle as does moving the axle farther forward from the center arch of the leaves, basically all are tipping the pinion downward the front of the axle up.

 

yeah, I am wondering now if my rear 80 springs where factory or not. I know my buddys 87 4 runner rears were stock for sure cause they were dang near flat when he took them off. I set both spring packs on the ground and didnt notice much dfference in arch from the two so I figured they were all stock packs. I will try to get some pics up tomorrow of how it sits with the 4 leaves and the chevys out back. Thanks.

 

Pics of the truck as it sits now with everything tacked on. This is the 4 leaf pack in the front and you can tell it still gives a good amount of lift for some reason. The last pic is it sitting beside a bone stock 82 with 33's and sagging front springs.