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Broken 5150, why?

BAC478

BAC478

NAXJA Forum User
Location
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The other night I was doing some really light wheeling up to a fire in the woods. Somwhere along the line I broke the top eyelet off my rear passenger shock. It was a Bilstein 5150 and it failed at the threaded connection between the eyelet and the shock body. It seems strange to me that it would fail under such light use unless it was already on its way out. The shocks have only been in the jeep for about 7 months and have only seen a few heavy wheeling trips. Could this be a problem with suspension geometry or something similar? The shocks are mounted to the unibody with the brackets for the rear sway bar welded where the bar pins used to be.

The place was full of frozen mud with deep tracks in it. Could the tracks pulling the jeep around caused a lot of lateral loading?
 
I would lean to a rare defect in the shock. Bilstiens are awesome, but they are built by humans. I would call then and see if they will replace it.

I have also drilled up into the body and put stud mount adaptors for my shocks. I like those because I get more of an option to turn it more to make up for any mis-alignment issues with the axle mount.
 
Having the upper mount rotated the wrong way will definately cause binding!
 
The jeep has an 8" lift and the shocks are the 12" version. I called up Clayton when I ordered the lift and asked what the recommended and they said about 12" at all 4 corners. There is plenty of travel in and out when the jeep is sitting level. Thats what I thought the problem might be too but it doesnt seem that way. I have the upper mount the same way as the bar pins where. So that the pin/bolt goes side to side in the jeep.
 
Were the shocks bottomng hard when you hit the ruts?

I'd say it was from bottoming hard or a defect.
 
if you have them bolted in the factory position on the unibody, there will be a definite stress on them. The original geometry of the rear suspension was to handle up and down movement of the axle and a very slight bit of side to side movement. So, when you have your rear axle flexed out, its pushing the shock to one side or the other as it extends or compresses. A remedy would be to either fabricate or purchase a set of upper shock mount tabs and relocate the top to a position more towards the center of the body, almost in a triangle, not too extreme of an angle, or it will cause an adverse effect on the suspension when driving it on the road.
 
I've run into a very similar problem with my rear passenger side 5150. The thread just stripped out and the now won't stay tight or even tighten up to the eyelet. I was thinking of JB welding it. I am running 10" travel back there on factory mounts with only 6" lift. Maybe I should cut and rotate my lower mounts also.

I haven't called Bilstien yet, maybe I should.
 
99XJWhitey said:
if you have them bolted in the factory position on the unibody, there will be a definite stress on them. The original geometry of the rear suspension was to handle up and down movement of the axle and a very slight bit of side to side movement. So, when you have your rear axle flexed out, its pushing the shock to one side or the other as it extends or compresses. A remedy would be to either fabricate or purchase a set of upper shock mount tabs and relocate the top to a position more towards the center of the body, almost in a triangle, not too extreme of an angle, or it will cause an adverse effect on the suspension when driving it on the road.
Click to expand...

The stock rear shock geometry is fine for what it is. When the axle articulates the shock eye will rotate on the bolt. There should be little bind in the rear shocks.

Since you turned the eye of the shock 90 deg. by using the swaybar mounts as a BPE, you f'd it up. It failed exactly where I would suspect it would.

You need to orient the top eye of the shock like it was stock and it won't happen anymore.
 
99XJWhitey said:
if you have them bolted in the factory position on the unibody, there will be a definite stress on them. The original geometry of the rear suspension was to handle up and down movement of the axle and a very slight bit of side to side movement. So, when you have your rear axle flexed out, its pushing the shock to one side or the other as it extends or compresses. A remedy would be to either fabricate or purchase a set of upper shock mount tabs and relocate the top to a position more towards the center of the body, almost in a triangle, not too extreme of an angle, or it will cause an adverse effect on the suspension when driving it on the road.
Click to expand...

While I understand your logic, this isn't true. The shocks work perfectly in the position that the Jeep engineers design ed them. The bushings easily have enough available movement to handle the slight shock movement at the top. Most folks run their rear shocks in the stock location, mine have been that way for well over 12 years of hard wheeling.
 
Goatman said:
While I understand your logic, this isn't true. The shocks work perfectly in the position that the Jeep engineers design ed them. The bushings easily have enough available movement to handle the slight shock movement at the top. Most folks run their rear shocks in the stock location, mine have been that way for well over 12 years of hard wheeling.
Click to expand...
X2,what may be more realistic is front to back movement caused by the extension/compression of the leaves,but I dont think thats more angle the a rubber bushing can handle.The front suspension travels alot more with no issiues.
Now,have you moved your shock mounts?Are you running any(what size) degree shims?
 
Could a lot of axel wrap stress the shocks this way? Pinion rotating up a few inches.
 
Stumpalump said:
Could a lot of axel wrap stress the shocks this way? Pinion rotating up a few inches.
Click to expand...

Shouldn't.....and his broke at the top.
 
The same thing happened to me when I was running the 5150s. The lower mount on a rear shock broke off. I JB welded it and it lasted the rest of the shock's short life. When I called Bilstein about it, they basically told me to pound sand. Those were the crappiest shocks I have ever run. They were trashed in less than 15k. All of the fluid leaked out of all four. In belistein's defense, I did use them hard, but have also run two sets of pro comps, a set of doetche techs and a set of Bilstein 5100's and they all held up fine. I must have got a bad batch.
 
I am running shims on the leafs but they are small. They were the ones that came with the clayton kit and are just enough so that the axle pinion is parallel with the driveshaft like it should be for a CV. I cut and rewelded the lower shock brackets to compensate for the axle rotation.

The only thing I can come up with is that it was either a material failure or the shock experienced too much stress from either the axle shifting side to side or from articulation...or both. With the bolts going across the jeep at the top, only flex in the bushings allow for side to side rotation of the shock. Maybe I need to flip the bolts so the shocks can change angle as the axle moves vertically?

99XJWhitey said:
The original geometry of the rear suspension was to handle up and down movement of the axle and a very slight bit of side to side movement.
Click to expand...
Yes but when the axle moves up and down the angle of the shocks has to change resulting in rotation at the top and the bottom end of the shock
 
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