SOA without cut and turn?? bad

[scrowley]

So on my new (to me) 87 fj60 it has SOA with add a leaf in all packs. It DOES NOT have a cut and turn. How bad is this and will it hang up the suspension from traveling or just have bad driveshaft angle? It also has a different driveshaft from a 94 runner with a double cardan joint. the front suspension has ford front shock hoops.

 

[Dynosoar]

So on my new (to me) 87 fj60 it has SOA with add a leaf in all packs. It DOES NOT have a cut and turn. How bad is this and will it hang up the suspension from traveling or just have bad driveshaft angle? It also has a different driveshaft from a 94 runner with a double cardan joint. the front suspension has ford front shock hoops.

This most likely will be a big problem. the front drive shaft on a 60 is short and the angle that you are asking the u-joints to work at is too severe. FJ62's can get away without a c&t because of the longer drive shaft. I do not have much experience with SOA, but I read a lot of posts.


This is not a problem at all


This is a good thing

 

[Cruiserdrew]

It's kind of half-assed though. You run a double cardan joint and point the pinion at the t-case output. If you don't do a cut and turn and change the orientation of the pinion, then a regular deive shaft would be as good (or bad) depending on how you look at it.

It sounds like your pinion angle is bad. This can lead to binding of the ujoint, especailly since the pinion rotates down under load.

FJ62s can get away with it, though it still isn't ideal, because the pinion has a different relationship to the perches and points up more, stock. This greatly eases that lower driveshaft angle. People talk about getting away with it on 60s, and I'm sure you can, but it isn't ideal.

You want to optimize 2 things-caster for safe handling and pinion angle to avoid binding and breakage. The only way to get it exactly right is to do a cut and turn.

Here is a pic where the u-joint angle is at zero and the caster is 2 degrees after a cut and turn.

 

[TBIFJ40]

Cruiserdrew is right. If you dont use the Carden joint, the angles at the pinion and the t-case have to be the same; as the joints go thru their motions, the angles cancel each other out, cancelling vibrations. With the carden at the t-case end, those two joints work in unison to cancell their own vibration, then ideally the yoke and u joint at the axle end needs to point directly at the t-case. The angles would be reallllly severe without the cut and turn.
Dont use angle shims in the front for two reasons: 1)They may not stay. The aluminum ones can distort and work out, which results in loose stuff in the front end which can result in your rig and you upside down in a ditch somewhere. 2) ruins your caster angle which isnt much good on the stock axle anyway. The angle helps your rig find center again after you trun, and keeps in straight on the road. 4 degrees is what you need to shoot for there.
The cut and turn is worth the time and effort! Good luck!!

 

[scrowley]

my last rig was a 85 runner with a lot of lift and no cut and turn which some people do on those. I remember the angle being terrible. the semi solution for it was a different year driveshaft that has more flex at the u joints. I never had a problem with it and i did some serious wheeling. I am sure that the front driveshaft will have to be extended so it doesn't fall out. The first pic is great of the cut and turn. nice job!! I don't know if i will want to get into all that if there is an easier and descent solution. I remember i did buy shims for the runner but never put them in. could you put in shims and tack weld them on the perches so they don't fall out?? ghetto but will it work. I have never used the shims on a lifted truck just some lowrider i've built. thanks one more thing do you have to just cut and turn the front axle right. I remember the rear of the runner was ok but the front was the bad angle. It had serious vibes on the road in 4x4 but on the trail in 4x4 it was fine.

 

[DirtyLittleSecret]

Im sorry to sneak in here, but I'm just curious...so the FJ62's dont need C&T? I keep thinking about what what I am going to do once my BFG's are bald (a looong time from now). Perhaps taking out a spring from each of my OME packs, doing a SOA w/ 38's, and 4.88's. Figure I'm building the rig already, but am rolling on 33's.

Someday. Maybe. Okay I'll admit it. Its a consideration.

 

[Cruiserdrew]

Im sorry to sneak in here, but I'm just curious...so the FJ62's dont need C&T? I keep thinking about what what I am going to do once my BFG's are bald (a looong time from now). Perhaps taking out a spring from each of my OME packs, doing a SOA w/ 38's, and 4.88's. Figure I'm building the rig already, but am rolling on 33's.

Someday. Maybe. Okay I'll admit it. Its a consideration.

In my experience you cant wear the BFG ATs out, so it will be awhile.


FJ62s have a pinion that is rotated up a bit. Not as much as you would want, but enough that you might get away with it. It isn't ideal.


If you're doing that much work and building that much truck, why wouldn't you cut and turn? If you look at the pic I posted above, that's an FJ62 axle and yep-it's cut and turned.

 

[lehiguy]

All I ever did was to set the caster angle and put in a CV with the appropriate length shaft. Never had a problem and I never did a cut and turn. I suppose that without the CV it would shake like mad, but as it is I can drive it down the interstate in four high when it snows and nothing happens.

 

[scrowley]

All I ever did was to set the caster angle and put in a CV with the appropriate length shaft. Never had a problem and I never did a cut and turn. I suppose that without the CV it would shake like mad, but as it is I can drive it down the interstate in four high when it snows and nothing happens.

This is what i thought. I cut and turn should be done in theory but what are you going to do... time, more money for maybe not all that much of a gain. It is a deffinate that the driveshaft has to be longer. I was not aware of the cv joint taking away the shakes. Why is this? Can it hold up to just as much abuse?

 

[lehiguy]

This is what i thought. I cut and turn should be done in theory but what are you going to do... time, more money for maybe not all that much of a gain. It is a deffinate that the driveshaft has to be longer. I was not aware of the cv joint taking away the shakes. Why is this? Can it hold up to just as much abuse?

I've had a CV on both my front and rear drivelines for years. They require frequent greasing, at least as often as you change your oil. They are very strong, don't worry about that. The theory is that the two u-joints that comprise the CV or "double cardon" joint act together just like a typical driveline would when it's in phase and the u joints at both ends are in agreemant as to their angle. Therefore, when using a CV joint, the other end of the driveline SHOULD be straight, meaning the driveline and the flange to which it mounts are at 90 degrees from each other when under a load. This is critical on a rear driveline, but you can get away with less than perfect angles on the front, the CV makes the whole thing more forgiving.

 

[scrowley]

I've had a CV on both my front and rear drivelines for years. They require frequent greasing, at least as often as you change your oil. They are very strong, don't worry about that. The theory is that the two u-joints that comprise the CV or "double cardon" joint act together just like a typical driveline would when it's in phase and the u joints at both ends are in agreemant as to their angle. Therefore, when using a CV joint, the other end of the driveline SHOULD be straight, meaning the driveline and the flange to which it mounts are at 90 degrees from each other when under a load. This is critical on a rear driveline, but you can get away with less than perfect angles on the front, the CV makes the whole thing more forgiving.

can you post some pics?

 

[lehiguy]

can you post some pics?

Here you go. The rear is a GM semi-floater 14-bolt with 1-ton Spicer driveline hardware. You can see that the pinion is pointed straight at the driveline. (You can also see my name written on my driveline from it's last visit to Six States driveline shop. I figure it will help me find it if I lose track of it.) That's how it should be when using a CV joint on the other end. The front shows the pinion a little lower than ideal, but it works great.

 

[scrowley]

Here you go. The rear is a GM semi-floater 14-bolt with 1-ton Spicer driveline hardware. You can see that the pinion is pointed straight at the driveline. (You can also see my name written on my driveline from it's last visit to Six States driveline shop. I figure it will help me find it if I lose track of it.) That's how it should be when using a CV joint on the other end. The front shows the pinion a little lower than ideal, but it works great.

looks good but the gm rear seems to have a different angle with no need for the cut and turn. it looks like some perfect angles.

 

[GulfShoresFJ60]

looks good but the gm rear seems to have a different angle with no need for the cut and turn. it looks like some perfect angles.

You don't need to cut and turn the rear. When you weld the perches on top of the axle you set your pinion to the desired angle and weld the perches.

The only reason you cut and turn the front axle is due to the caster changing when the pinion is rotated.

 

[Cruiserdrew]

You don't need to cut and turn the rear. When you weld the perches on top of the axle you set your pinion to the desired angle and weld the perches.

The only reason you cut and turn the front axle is due to the caster changing when the pinion is rotated.

x2. You just turn the rear, no cut!

 

[scrowley]

x2. You just turn the rear, no cut!

So if i just reweld the perches to get a good ds angle then what happens with the bad caster?

You don't need to cut and turn the rear. When you weld the perches on top of the axle you set your pinion to the desired angle and weld the perches.

The only reason you cut and turn the front axle is due to the caster changing when the pinion is rotated.

Is this a good way to go. Is there any other way to adjust the caster without the cut. what are the pros and cons to just repositioning the perches to get a good ds angle? I'm sorry i am a little slow on this but i guess this is how you learn right. thanks a lot

 

[Randy88FJ62]

The best way to visualize caster it to go out to your old bike. If you relocate the fork to a different angle back towards the bike to the wheel is closer to your knees then it becomes hard to turn and shaky at speed. This is the reason why a cut and turn is done. There are two variables on your front axle that need to be tuned. One: The pinion angle which is the angle at which your driveshaft relates to the transfer case. This pinion angle must be correct so that the U-Joints don't bind. Two: Caster. This is related to your steering as I tried to give an example of with a bike. If that is not corrected then it puts more stress on your driving system trying to turn and it also has instability at speed. So, in closing, you rotate the pinion angle to meet the driveshaft requirement and weld the perches on to hold this postion. Now your steering is not lined up because the perches have moved positions. This means that you have to cut into the axle and readjust or turn it to get that proper steering geometry back.

 

[Mace]

Castor is not an issue on the rear of the truck.

Also, you should have the spacer between your tranny/tcase. That will give you a longer front DS and make it easier on your joints.

And the pics that Lehi posted are what just about everyone here is reccomending that you do, cut and turn your front axle to get the pinion pointing at the tcase..

It is possible to not do the CNT and get away with it. but you already have a CV driveshaft. And a CNT is not that complex at all. Are you doing the SO yourself? If so, there is no reason in the world why you could not do a CNT yourself.

 

[scrowley]

Castor is not an issue on the rear of the truck.

Also, you should have the spacer between your tranny/tcase. That will give you a longer front DS and make it easier on your joints.

And the pics that Lehi posted are what just about everyone here is reccomending that you do, cut and turn your front axle to get the pinion pointing at the tcase..

It is possible to not do the CNT and get away with it. but you already have a CV driveshaft. And a CNT is not that complex at all. Are you doing the SO yourself? If so, there is no reason in the world why you could not do a CNT yourself.

I just bought the truck and the soa is already done. I know about the rear having no caster because it is fixed. I just don't understand the difference of rewelding the spring plates and c&t being different. Is it the binding that would be caused. Lets say i just leave it how it is. soa, cv driveshaft. would this hurt articulation or cause something to break. How hard would it have to be wheeled in order to due damage. Or is it just the vibration factor in 4wheel drive at higher speeds. I know my 4runner had some BAD angles in the front but it seems the cv joint flexed enough so it wasn't a issue. It had about 8" lift.

 

[Randy88FJ62]

You have the potential for two problems:
1. High speed 4wd may have vibrations
2. during low speed 4wd at maximum articulation you may have binding.