What causes leaf springs to fan?

[anthrax323]

This sounds like a dumb question, but what causes leaf springs to fan out? I have RE 3.5" rear leaf packs, and my driver side pack seems to fan relatively quickly without fail. It's never rubbed the tire, but I want to put an end to it without using additional clamps (which is probably impossible).

My XJ had frame damage from a rear-end collision when I bought it (didn't know at the time, but that's a story for another day) which has since been pulled, so my theory is this...

Is it caused by the ends of the spring being slightly off parallel from each other (horizontally) or something else? Manufacturing defects, maybe?

I'd like any input you guys have to give, as I'd like to cure the source (if possible) rather than using a bandaid like more clamps.

 

[Cottontail]

I don't have an answer, but I will second your problem. My RE 3.5 spring does the same thing on the driver's side, but with an 8.8 it actually does rub the tire since I don't have a spacer yet.

Interested in the suggestions/answers.

 

[billyjp2]

i broke a center pin on my RE leafs which caused my leafs to fan out. the problem stopped when i replaced the pin.

 

[1990heepxj]

my deavers on my ranger always used to do it on both leafs, my yota crawler used to do it on both leafs, my brothers deavers on his ranger used to do it, my xj and my brothers xj both do it and we have diff leaf packs. other then more clamps i dont think theres much you can do about it

 

[CharlesS]

This was a problem I had, but the problem was caused by the loosening of the U bolts.
If you have replaced the leaf springs and U bolts you should check the torque on the U bolts a couple times over the next month due to stretching and settling. IIRC the U bolts need to be torqued to 120 ft/lbs.

 

[_87_XJ_]

x2 I just straightened mine out the other day and found the U bolts were pretty loose.

 

[1990heepxj]

i checked my u bolts like every week because the fanning pissed me off but it made no difference for me

 

[WB9YZU]

Fanning in flex?

If you don't use spring clips like they have on stock springs, they will do that.
RE and Rusty's springs have "Retainers". These allow a certain amount of fanning before limiting further separation.

Rotation side to side? Center bolts just center the spring on the perch and each of the leaves above it. A solid perch and properly tightened U-Bolts will limit that somewhat, however, the "cure" is spring clips on at least one side of the spring pack, I would do the front.

 

[CherokeeManatee]

My RE pack does this too, about an inch on each side with the lower leafs over a year. Loosen ubolts, hammer in, tighten ubolts - done.

I probably should get more spring clips though.

 

[rocknxj]

My RE pack does this too, about an inch on each side with the lower leafs over a year. Loosen ubolts, hammer in, tighten ubolts - done.

Zackly. I went to a slightly higher torque and have not had a problem. 120 ft/lbs should cover it.

 

[1990heepxj]

my deavers and my brothers deavers and RE leafs all had a clamp front and rear but 2 or 3 lower leafs were short and didnt go to the clamp. we only had problems on those lower couple not the ones in the clamps

 

[anthrax323]

Ditto. Only the lowermost leaves are fanning on my RE driver side pack (those not secured by the primary clamps). I just find it odd only one side is doing it.

At least I've finally trimmed the U-bolts, so my deep sockets should fit and allow me to get a 24" socket wrench on them. We will see if this helps, but I'm still curious what forces cause them to fan in the first place.

 

[RCP Phx]

To answer everyones question,the leaves fan out because the axle "yaws" when flexing the suspension.

 

[fathan16]

what would cause it to yaw? would shackle relocators help? cuz mine currently are pointing at the ground. or would bad spring bushings also cause this?

 

[souske]

The nature of leaf springs causes the yaw. When one side goes up, it also goes back changing the yaw of the rear axle