Steering Floating

[martymart]

My 1971 FJ40 has been driving fine. I had built a wooden drawer system to fit the bed for camping and spares and no issue with steering due to the extra weight. However, I put the hardtop back on my FJ40 and taking it out on a drive I noticed the steering changed with the front tires feeling lighter and slightly less control. Visually I do not see any rear sag. The springs are in great shape (HFS 4” lift) and I already have 6 degree caster shims on both axles with 2 1/2” higher than stock shackles. I am running 35x12.5 mud tires with hi steer steering and mini truck hubs. I use the Land Cruiser for weekend trips camping and crawling. I do not have any pics with the hardtop on since I just installed it this weekend. Would it be just the caster in the front, rear or both? Could shocks assist in fixing this issue? If shocks may help any suggestions on brand and model. I have 4Plus reverse u-bolts so the rear shock mount is longer similar to the later FJ40.

 

[JohnnyC]

Your now top heavy… It’s a tall truck with now the top on

 

[B y r o n]

It sounds like your problem is weight distribution. Your extra weight over the rear axle is unloading weight on the front axle and causing your steering issue. I'm not exactly sure what is the best way to address this other than adding more weight to the front.

 

[martymart]

Perhaps shortening the from shackles form 2

It sounds like your problem is weight distribution. Your extra weight over the rear axle is unloading weight on the front axle and causing your steering issue. I'm not exactly sure what is the best way to address this other than adding more weight to the front.

Perhaps shortening the front shackles to 1 1/2” over stock rather than the 2 1/2” and keep the rear shackles at 2 1/2” over?

 

[pb4ugo]

You might try playing with air pressures. My pickup truck does this to when I put a significant load in the bed, like a slide in camper and a FJ40 on a trailer. I usually increase rear pressures to the max and slightly reduce air pressures in the front to get more tire contact with the road.

What was the caster angle b4 adding any weight? A shorter shackle can slightly help caster too. A 1" reduction pin to pin reduces frt ride height by a 1/2".

 

[pb4ugo]

You might try playing with air pressures. My pickup truck does this to when I put a significant load in the bed, like a slide in camper and a FJ40 on a trailer. I usually increase rear pressures to the max and slightly reduce air pressures in the front to get more tire contact with the road.

What was the caster angle b4 adding any weight? A shorter shackle can slightly help caster too. A 1" reduction pin to pin reduces frt ride height by a 1/2".

Not knowing what your tire pressures are, your tires maybe under inflated which might allow the sidewalls flex more with the additional weight.

 

[martymart]

You might try playing with air pressures. My pickup truck does this to when I put a significant load in the bed, like a slide in camper and a FJ40 on a trailer. I usually increase rear pressures to the max and slightly reduce air pressures in the front to get more tire contact with the road.

What was the caster angle b4 adding any weight? A shorter shackle can slightly help caster too. A 1" reduction pin to pin reduces frt ride height by a 1/2".

I will play with the psi. Thanks for the recommendation

 

[martymart]

I will play with the psi. Thanks for

 

[martymart]

Not knowing what your tire pressures are, your tires maybe under inflated which might allow the sidewalls flex more with the additional weight.

On pavement at 35 psi. Off pavement 10-15 psi depending in terrain.

 

[pb4ugo]

On my 40, years ago my tire installer put 35psi in them. I thought it handled like crap. I aired them down to 26ish and it was much better. Later I went to 28 and got a couple more mpg's and it handles fine.

 

[peesalot]

Check tightness of front shackles & bushing condition, trunion bearing tightness. Slightly worn trunions, slightly loose shackles and/or worn bushings will all show up in steering feel which has been amplified by the now top heaviness. If all are good the idea to put shorter front shackles on is my suggestion as well.

 

[65swb45]

/this\

Also, do you have a mechanical locker in the rear differential? It makes a difference.

 

[martymart]

/this\

Also, do you have a mechanical locker in the rear differential? It makes a difference.

I have air lockers in the front and rear.

 

[peesalot]

It occurs to me after seeing Mark's post, that if your toe in is zero or marginal the heavier rear could cause the drift, a slight increase in toe in to a MAX of 1/4" wouldnt hurt if its not already there. Wheel bearings as well, once loaded ran in a certain line, now less loaded tend to wander if they are worn, all these are possible.

 

[martymart]

It occurs to me after seeing Mark's post, that if your toe in is zero or marginal the heavier rear could cause the drift, a slight increase in toe in to a MAX of 1/4" wouldnt hurt if its not already there. Wheel bearings as well, once loaded ran in a certain line, now less loaded tend to wander if they are worn, all these are possible.

Thanks. I have 1/8” toe in so maybe go to 1/4”. I rebuilt the knuckles last year so should be good there. I appreciate the suggestion and will put them into action.

 

[peesalot]

You have a winch, I mean honestly, a nice bumper/winch, maybe a dual battery set right behind headlight would be close to countering the weight and add stuff as opposed to looking for an issue that may just be a non issue. I would bet dimes to donuts its just the difference in the front shackles reaction to force, when I feel loosness, like slow reaction to steering in a corner its always the shackle either loose or bushing gone, literally. FWIW on half dozen trips a year I would expect bushings to last 1 year, two was good, 3 was great, 4 was neglect. I would drive it a bit and see if you scare the crap outa yerself or its just a little loose and you get used to it. My 40 you would stay behind the wheel on the road, I think its a slot car, all in the feel, you may just learn to love it.

 

[martymart]

You have a winch, I mean honestly, a nice bumper/winch, maybe a dual battery set right behind headlight would be close to countering the weight and add stuff as opposed to looking for an issue that may just be a non issue. I would bet dimes to donuts its just the difference in the front shackles reaction to force, when I feel loosness, like slow reaction to steering in a corner its always the shackle either loose or bushing gone, literally. FWIW on half dozen trips a year I would expect bushings to last 1 year, two was good, 3 was great, 4 was neglect. I would drive it a bit and see if you scare the crap outa yerself or its just a little loose and you get used to it. My 40 you would stay behind the wheel on the road, I think its a slot car, all in the feel, you may just learn to love it.

 

[martymart]

Have the winch and dual batteries. I believe the shackles and bushings are good but I’ll recheck the bolts and nuts

 

[pb4ugo]

It looks like you might be riding more in the center of the tire. You can get some chalk and spread it across your tread, roll the vehicle forward so the chalk marks on the driveway or road and look at the contact patch.

 

[peesalot]

I have similar steering. FWIW, have you checked pitman ? Give it a little pry with bar and see if the end has a little wiggle up & down when resting , tires straight ahead ? Is ps fluid & system good ? I cant tell from pic but if the ears/ or ends of bushings are gone the leaf eye can push over with steering force.