I hate BDS leaf-springs

[Oil Town XJ]

I'm sure getting tried of my bds leafsprings, I have gone through 4 leafsprings in the last year! They all keep losing there centre bolt, then shim slides out and the rearend tries to pass me. I haven't noticed any axle wrap and I'm getting tired of replacing them.

The failure I had again today almost killed me! I was passing a car on the highway and the second I let off the gas after I got around the car the Jeep dove to right and was headed for the ditch. I was just able to control the vehicle enough to stop safely.

When I got out to take a look I was missing my centre bolt and shim and the axle had slid 4" forward on the passenger-side. There was only 5000km's on that leaf!

 

[ROBZ95Xj]

maybee its the shims:dunno: or the ubolts coming loose

 

[Oil Town XJ]

maybee its the shims:dunno: or the ubolts coming loose

After the first one came apart on me I'm pretty anal about checking the torque on the u-bolts.

 

[ktm racer 419]

def sounds like the u-bolts working loose/stretching.

did you replace them every time you replaced the leafs?

and what degree shims? steeper ones will make the head of the centering pin want to XXXX to one side when torqued and that could be causing an issue (though not common)

do those use a 5/16" center pin or 3/8"? maybe its time to drill it out a size larger?

 

[techno1154]

Did the center pin go through the shim?
As said in the post above, try using a 3/8" bolt grade 8 going through both the springs and shim. Also use a good quality 'U' bolt not the discount parts store offering and torque them to specs. Re-torque them after a few miles. I find they have a tendancy to stretch so I re-torque them a few times when any work is done on the springs.

 

[WB9YZU]

This is not a spring issue, but a torque issue.

Let me explain:

As with most everything we do with fasteners, we stretch bolts to a certain length, an rely on that pull to not only hold the nut on (Thread friction), but to hold together tightly whatever we have applied them to.

The spring clamp bolts have a torque spec of 75ft/lbs. That stretches the u-bolts and hold the springs in place. That is the only thing which holds the springs in place. Think of it this way-The Sole purpose of the Centering bolt is to hold the springs together and provide alignment on the spring perch. Everything else is torque. If the center bolt is breaking, it is because it is being asked to handle more load than it was designed for.

Why would you loose torque on the U-Bolts? Weak bolts (not right grade), deformation of the spring perch, or something in the pack compressing.

If you have a set of aluminum shims: Ditch them. The compress and crumble over time which leaves you with loose u-bolts. The best ones are steel and allow you to make the ship part of the spring pack by you cutting the center bolt and installing as the last leaf (Requires new center bolt ).

Use good grade U-Bolts. They MUST also be re-torqued after 200-300 miles to deal with stretch.

Spring Perch. Look at that guy real well. Chances are by now, your perch is deformed (not flat). Check it.


Best of luck!

 

[VAhasnoWAVES]

This is not a spring issue, but a torque issue.

Let me explain:

As with most everything we do with fasteners, we stretch bolts to a certain length, an rely on that pull to not only hold the nut on (Thread friction), but to hold together tightly whatever we have applied them to.

The spring clamp bolts have a torque spec of 75ft/lbs. That stretches the u-bolts and hold the springs in place. That is the only thing which holds the springs in place. Think of it this way-The Sole purpose of the Centering bolt is to hold the springs together and provide alignment on the spring perch. Everything else is torque. If the center bolt is breaking, it is because it is being asked to handle more load than it was designed for.

Why would you loose torque on the U-Bolts? Weak bolts (not right grade), deformation of the spring perch, or something in the pack compressing.

If you have a set of aluminum shims: Ditch them. The compress and crumble over time which leaves you with loose u-bolts. The best ones are steel and allow you to make the ship part of the spring pack by you cutting the center bolt and installing as the last leaf (Requires new center bolt ).

Use good grade U-Bolts. They MUST also be re-torqued after 200-300 miles to deal with stretch.

Spring Perch. Look at that guy real well. Chances are by now, your perch is deformed (not flat). Check it.


Best of luck!

long story short... take care of your nuts.

 

[ECKSJAY]

If you have a set of aluminum shims: Ditch them. The compress and crumble over time which leaves you with loose u-bolts.

After using/installing these on customers' vehicles for YEARS with excellent results, I wholeheartedly disagree. Aluminum works just fine if you torque your junk and keep up on it until the bolts are broken in.

 

[WB9YZU]

Admittedly, my experience with aluminum shims comes from a rig I bought that was used on rock mining roads in CO. The shims dissinitigrated and wallowed out the perches. The rest of my experience has been with steel shims. With those, I have never seen a problem. For the cost difference, I won't even chance it.

 

[MoparManiac]

After using/installing these on customers' vehicles for YEARS with excellent results, I wholeheartedly disagree. Aluminum works just fine if you torque your junk and keep up on it until the bolts are broken in.

I used them on my XJ without a problem as well for close to 2 years.

 

[ktm racer 419]

why use aluminum shims when you can use steel?

you save a few bucks i suppose. but i have never heard of failures with steel and i have heard of many failures with aluminum.

 

[1990JEEPXJ]

im still confused as to why the OP thinks the center bolt constantly breaking is the leaf springs fault. i have heard nothing but good about BDS stuff. i have to go with the concensus here and attribute your constant problems to either shims and/or the u-bolts, or maybe the center pin was not installed tight enough when the shims were installed causing some slop at times. or even the center pin hole in the leafs, maybe leaf perch too, possibly being wallowed out now. just thinking out loud here.

 

[jeeperjohn]

I have BDS leafs and I had the aluminum shims break with similar results to what you had. I replaced them with steel shims and drilled out the leafs (this required a carbide burr on a drill press because the leafs are made of very hard metal) for larger grade 8 socket head cap screws. I also drilled out the mounting plate on the diff to accomodate the head of the allen head bolt. I have had no issues since.

 

[playwithit]

long story short... take care of your nuts.

 

[robsjeepxj]

How da like des apples? http://i.ytimg.com/vi/TjdpO-xoV50/0.jpg

 

[ericfx1984]

I agree with the the others... sounds like you need to make sure the u bolts get properly torqued and check them from time to time