caster (1 Viewer)

[tony58]

I have been working on my 1977 fj40 with a caster issue It has a 2.5 spring lift, and a 5 inch [center to center bolt] shackle lift running bf Goodrich mud terrain km2 33/10.5xr15 tires The font end is tight center arm is good I have tried 2.5- and 4-degree shims I still can't get the steering wheel to center after a turn, any help would be appreciated, it is a handful to drive I just put in the 2.5 and the 4 degree shim together and it is about the same, what am I missing?​

 

[-MaTTi-]

The problem is somewhere else than in caster. I would guess that it’s that electric power steering.

 

[tony58]

no ,I did disconnect the p/s and it did the same thing i'm thinking it could be because of the long shackles I would buy new ones if that is the issue.

 

[-MaTTi-]

i'm thinking it could be because of the long shackles I would buy new ones if that is the issue.

Don’t. How’s your knucle bearings?

 

[tony58]

i;m not sure how would i check them?

 

[-MaTTi-]

i;m not sure how would i check them?

Lift both front wheels up and turn tires left and right by hand. Should be smooth and easy to turn, no any steps. Take the relay rod off to get more precise feel.

 

[tony58]

will try ,thanks again

 

[pb4ugo]

I guessing in the angle finder pic the frt of the vehicle is to the left? If so do you still have the stk shackles?

 

[tony58]

yes, you are correct no I do not have the stock shackles

 

[pb4ugo]

With the 40 on the ground at ride height is the back end higher than the frt or is it level? Are the rear shackles the same as the frt? That much shim and still shows it needs more, I think something is off. Have you put a 4 ft level on the floor to see how level it is? Id make sure to dial the 40 in. You can put the 40 on jack stands under the axles and level the frame. Stk shackles are 2 3/4 long. The amount over stk nets you about 1/2 in ride height. A longer shackle pushes the frt of the spring downwand and rotates the axle to -caster. Needing 12*+ on a 2.5" lift is nutz.

 

[Mr. Green]

Second question asked was about toe in and we don’t know where it’s at. I would double check yours and report back.

 

[RevISK]

Second question asked was about toe in and we don’t know where it’s at. I would double check yours and report back.

This^^^

I made a set of toe in jigs out of two pieces of aluminum angle, super easy to set toe now.
Makes a huge difference if it’s out.

 

[tony58]

shackle is the same on rear will level this week these are the spec's before i put the shims in the correct way.On the toe issue thats all they could get,thanks again and again would shorter shackles be any better

 

[pb4ugo]

shackle is the same on rear will level this week these are the spec's before i put the shims in the correct way.On the toe issue thats all they could get,thanks again and again would shorter shackles be any better

View attachment 3450805

Sooo, the caster shims were installed bachwards with the fat end towards the rear and caster was approx -4*? Were the shackles install too?

 

[RevISK]

Going to stock or thereabouts shackles would eliminate the need to shim so much but if your shim were backwards then that’s your problem.

I have 3” center to center shackles from cruiser outfitters and a spring lift that came on the truck, maybe 3”. After TRE’s, setting the toe and replacing worn out spring bushings, my truck steers much better. I wanted to get to this point so I could properly determine my caster angle then order shims from there.

 

[RevISK]

My DIY toe in jig.

 

[pb4ugo]

Sooo, the caster shims were installed bachwards with the fat end towards the rear and caster was approx -4*? Were the shackles install too?

If this is the case, logic would say if you installed the 4* shims properly you would have 0 caster. And if you installed 6* properly you would have 2* positive. You dont seem to give us all the info. There's no mention of having alignment specs. You keep us guessing and then you want a definitive answer with limited info.

 

[77mustard40]

None of these caster numbers make any sense for a "2.5 inch lift". I'm running a 4 inch Skyjacker spring up from with a 4 degree shim and have positive caster and no handling or steering issues. Suggestions for moving forward without opening your wallet and just throwing money at it...

1. Remove the shims and measure caster with your angle finder, be sure your floor is flat and if not adjust your findings for the floor. Post results.
2. Identify the springs on your truck (make model etc.) Did you purchase them and from where? Are they oriented the correct direction? They look really flat in the photo's so I'm wondering if they were designed for a 40. Post results.
3. Did you install the extended shackles or did they come with the truck. Any history of the truck's suspension may help. Reducing the length of the shackle will help but its not going to come close to solving the problem (as we know it)
4. Let's get some distance shots of the truck so we can see the stance, placement of the wheels in the wheel wells etc. Angled from the front, a side shot, and angled from the rear.

Last thing, why are the u-bolts so darn long?

 

[tony58]

I bought the 40 and the springs and shackles were already installed the springs came from sor. u bolts are long because I needed new ones and the shop only had that length but I did cut them down today. will get pictures and drop shims and then measure caster this week where is the best place to put angle finder? Would it be on the bearing cap as pb4ugo said,thanks

 

[RevISK]

“Would it be on the bearing cap as pb4ugo said”

Yes.
Just be sure you are on as level of ground as possible, otherwise, determine the grounds “level” and use that as your zero (elementary math needed here).

 

[pb4ugo]

I've set up multiple frt ends. I've found the bearing caps are about as close as your going to get without disassembling the frt end. Dont use the nuts or studs. Equalize the tire pressures. When I did my own 40 I used 4 jack stands under the axles with the weight of the vehicle on the suspension and i leveled the 40 frt to back and side to side using the straight part of the frame under doors and my straight bumper. You can catch the edge of the cap with the angle finder.

The best info you have is from the alignment rack. What was the orientation of the shims and what degree shims were installed? You can probably build off those #'s.