Suspension bolts

[Scott'n'Wendy]

Kind of a myth, the brittle idea. Higher strength means stronger. The breaking strength of gr8 is higher than the stress where gr5 bends. True that gr8 breaking strength is closer to its ultimate strength than is gr5's. Where gr5's yield, gr8's hold together. Gr5 yield is 72000psi, gr8 yield is 90000psi.

I thought in shear they were lower than 5. That is not true?

[Scott'n'Wendy]

Thanks, yea I went back and looked at all the stuff you, Scott and Gyrogearloose were doing which helped reinforce my decision to get this system installed. Pretty sure it should keep the lateral axle movements in check.

Just to clarify, it was just Cate&Rob and Gyro doing that work. Not me. I'm a wiring guy, I'm not a mechanical guy..... though I try to imitate one every now and then.

[AlexPeterson]

TedS is right. Grade 8 is a stronger bolt in all regards than a grade 5. Any load that would fail a grade 8 would have easily failed a grade 5.
Scott'n'Wendy Shear strength is a bit complex, but relates directly to the tensile strength.

A quick search of the web seems to show this myth of grade 5 somehow being better for suspension parts than grade 8 has persisted a long time. Kind of like the one that says hot water freezes faster than cold...

nprario Great solution. While there will be a little forced lateral motion as the left side suspension travels up and down, I suspect it is a lot less than the side loads during tight turns. There will be more cycles of this smaller load though, so time will tell.

A full tight turn of a 5th wheel with almost no forward motion, for example, on asphalt puts a side load on the suspension approximating the axle load. So, if the axle has 6,000 lbs on it, there will be a force somewhere approaching that magnitude pushing sideways on the springs. Without the track bar modification, this load puts a bending load on the hangars, hence cracks such as what Yoda has documented.

[Scott'n'Wendy]

Has anyone used the never fail bushings? I realize they will fail, but probably better than a dry bronze bushing if I go to solid bolts on the upcoming suspension teardown?

[Cate&Rob]

Scott'n'Wendy I bought a set of Never Fail bushings from Lippert at a National Rally. “Guaranteed to fit all locations”. They only fit the spring eyes and that took some work. I don’t think they are available anymore. There are internet pictures of failed Never Fail bushings . . . might be the reason they are no longer for sale.

Rob

[Jlawles2]

Cate&Rob Rob, quick search found the below picture with its claim. I think it's false advertising. Also note they are out of stock...

[Cate&Rob]

Jlawles2 . . . 100,000 miles on a trailer . Hmmmm

Rob

[ajg617]

Scott'n'Wendy I bought a set of Never Fail bushings from Lippert at a National Rally. “Guaranteed to fit all locations”. They only fit the spring eyes and that took some work. I don’t think they are available anymore. There are internet pictures of failed Never Fail bushings . . . might be the reason they are no longer for sale.

Rob

They don't fit the shackle/CRE3000 bolts? There are some still available through second sources but not from Lippert. But the real question is did you install them and are they holding up better than brass/bronze?

And yet another question(s)? Are the triple axle kits the same size as the tandem and all have 9/16 bolts? I was able to locate a triple axle kit (bolts and neverfails) for a reasonable price. Wondering if that will work?

[Cate&Rob]

_{They don't fit the shackle/CRE3000 bolts? There are some still available through second sources but not from Lippert.}

At the time, I was running the LCI “Equaflex” equalizer and the OD of the LCI Never Fail bushings would not fit the ID of the hole in the LCI equalizer . . . although the LCI rep at the rally promised that they would. I was able to get these bushings into the spring eyes, but the compression required to do this caused a very tight fit to the bolts . . . particularly because the bolts were to be inserted dry.

I believe that there is a reason that LCI no longer sells these. Google “Never Fail bushing failure”.

Rob

[Scott'n'Wendy]

Google “Never Fail bushing failure”.

Rob

I agree they will fail. Google wet bolt failure or bronze bushing failure and you will likely get far more horror stories. It's a guarantee the bushings will not survive. At least in the spring eyes. But do you think something composite like never fail bushings would be better or worse than bronze that is only greased on installation?

[Cate&Rob]

Scott'n'Wendy

The root cause of the problem is the small diameter, out of round, eyes in the springs. This seems to be an industry standard for trailer springs . . . but, doesn’t have to be. There is room for a larger diameter spring wrap that could enclose a bushing with a steel inner and outer with a bonded rubber bushing . . . like any other car/truck suspension bushing.

A bronze bushing deforms into the gap at the end of the spring wrap and stays that way. The concept of a plastic bushing that would compress and recover seems like a good idea and likely is what LCI was going for with the “Never Fail” material . . . it just didn’t work. In my suspension iterations, I pulled bronze bushings with less than 500 miles on them that were already deformed and wearing excessively.

Rob

[TedS]

Cate&Rob, agree. And.it would help to increase the diameter of the bolt.

[AlexPeterson]

Track bar (pan hard bar) are intended for those suspension systems that do not have a method for preventing lateral motion of the differential. Most notable uses are trailing arm (Ford and Dodge SFA axles), race cars with straight bar supports and coil springs (non triangulated) and coil spring systems. Leaf spring systems are not by nature trailing arms (i.e. pushing the axle) but follower systems and the use of a track bar is not needed as it will induce lateral stress into the leaf springs. I cannot recall ever seeing a track bar on a leaf spring setup. In your picture, note the coil springs (grey) and trailing arms (orange), this is a very common setup in modern SFA vehicles. Any play in these components also leads to the dreaded DEATH WOBBLE as the axle naturally wants to FOLLOW the attachment point vs being pushed by it.

LOL, never thought to go look at the Jeep I have in the shed until now. Here are pictures of the front suspension track bar on my stock 1988 Jeep YJ with leaf springs. The frame attachment is on the vehicle's left side, differential attachment is on the right.

[Jlawles2]

AlexPeterson I see you still have the front swing shackles. I thought that was one of the first things people changed. This also helps make the front less susceptible to something similar if not Death Wobble. Any time you PUSH something (think shopping cart front wheel) it naturally wants to follow unless you prevent it. Backing up a BP trailer is another prime example, when pushing it backwards it's doing everything in its power to try and follow. Not a Jeep guy, but for some reason I though the swing shackle on the front put the spring eye in front of the mounting point.

from the web: Why install a Shackle Reverse System (S.R.S.)™? Because it allows the front suspension to travel in a much more natural action when the spring compresses. In stock form (shackles in front of the front axle) when the front tire comes in contact with an obstruction, the impact is partially transmitted back to the frame via the solid rear pivot point.

[Scott'n'Wendy]

[USER="4775"] seems like a good idea and likely is what LCI was going for with the “Never Fail” material . . . it just didn’t work. In my suspension iterations, I pulled bronze bushings with less than 500 miles on them that were already deformed and wearing excessively.

Rob

So which one do you think is better? 500 miles on the bronze and already worn excessively...I've heard of worse.....so composite may be better? How long did it take the never fail composite to fail? Bronze obviously is a quick failure..so....I have a choice of nylon, bronze, never fail (If they can still be found).....which would you pick with a solid bolt?
Take nylon over bronze? Never fail if you can find a set?