YJ: Third broken front leaf spring since 3-2011

[Roger]

I have RE 4.5" leafs front & rear on my YJ. I have had three front leaf spring break. Two on the driver's side and one on the passenger side.

The Jeep has power brakes and is equipped with an aftermarket booster that is huge.

If the brakes are applied very hard, the front end really dips.

The ride is pretty soft so I'm wondering if that's what's causing the leaf springs to fail. Like maybe a reverse axle wrap??

Okay all you Jeep geniuses, what say you??

[6spdYJ]

Are they breaking near the axle tube, or the frame, or the shackle? It could be that the length of each supporting leaf is too long and allowing the main to gullwing. Just a guess though.

[Roger]

Are they breaking near the axle tube, or the frame, or the shackle? It could be that the length of each supporting leaf is too long and allowing the main to gullwing. Just a guess though.

They are breaking right behind the axle

[6spdYJ]

Sounds like the spring is wrapping under braking. One thing you may consider - at the expense of losing 1/4" of height in the front is to slip a stock second or third leaf on top of the pack and see if they quit breaking. What you would be doing is sharing the braking load from the point behind the axle and spreading it along the length of the front and essentially pulling down on the shackle. John Cappa used a similar method of fighting axle wrap on spring over jobs.
Consider swapping in a booster from a '95 YJ. It was the only year that used a dual-diaphragm and is supposed to be a good improvement over the singles. Another thing about it is that it was used as an OEM part on flimsy 1/4" thick leaves, so it probably won't hurt the RE's which I assume are 5/16" (?)
Another question, do you have clamps on the springs? They should be open enough to let the leaves move freely, but not open enough that they aren't controlled when they try to separate.

[aw12345]

First question to ask would be are the spring all breaking in approximately the same spot?
Pics also help, is it always the main leaf that breaks?

[Roger]

Yes, the same location, right behind the axle housing
Yes always the main spring that breaks.
I'll try to take a photo tomorrow and post it up.

[Jason]

Have you consider an angle issue? To me it sounds like the spring is binding and maybe getting twisted side to side.

[dirtman13]

Too much skinny peddle.

Sounds like axle wrap to me. I ran those exact springs on my CJ for a few years with no issues. Like Art said. Pictures might help.

[NAILER341]

Are your shackles inverting? If they are flipping backward and slapping into the frame where you have to pry it back forward this is the culprit. you will need to either add something to the frame to prevent the inversion or get the boomerang shackles with the least amount of lift and install those to prevent the inversion.
I can almost guarantee this is what is causing the spring failures.

[Lumpy Grits]

Is it the top spring leaf?
If so, put a good radius in the edge of that spring pad.
Also, does this spring pack still have the clamps on? That is the biggest thing the claps do is to keep the leafs working as one to reduce this damage.
LG

[Roger]

Jason - when the axle is fully articulated there is a lot of side twist to the spring.

Actually Chuck, it seems to be too much fat pedal. I wonder if the after market power brake booster is too much braking. Anyone know anything about proportioning valves?

Erik - no the shackles aren't inverting. I don't think they ever did when Mitch owned the Jeep either. I seem to remember he had some issues with the real shackles but not the front ones.

The length of the shackles are 5" center to center of the bolts

Lumpy - Yes it's the top spring. Not sure about clamps. there's a "clamp like" thing that has a gap on the top side. Look at the last photo below.

[Lumpy Grits]

It ain't the brakes. If it was, both sides would be breaking.
It is the twisting the spring sees when you drop the wheel. I have seen the driver's side do this far more than the PS does.
The sharp edge of the axle pad is a stress raiser(think, knife edge). That is why I put a full radius in that part of the pad to spread the stress over a larger area.
Also make sure your spring "U" joints are torqued to the correct specs.
Is there a wedge/angle spacer between the leaf and pad? Is it steel or alum?
Gary

[aw12345]

I would take a shorter leaf from one of the old springs and add that on top of the spring pack on both springs.
That will spread the load better on the main leaf. Next I would check compressed shock length versus bump stop.
Reason being when crawling the left front wheel tends to go on the bigger rocks since you can see the tire.

[Lumpy Grits]

Btw, Roger, you need to replace that leaking pinion seal and see why it's leaking.
LG

[6spdYJ]

Your clamps could stand to have the cross pin lowered. You only need enough room to let the leaves move as independently as they can (considering the centers are bolted and clamped) About 1/4" gap is fine. It will also help the front end of the spring pull down farther out toward the shackle and spread the load throughout the whole pack. It's probably your fastest and most cost effective thing to try. The bummer is, if that don't do it...