hit a really big road repair this morning and then "clunck!"

[The Roadie]

Thanks for the play by play. I agree the shock of unloading the suspension is a killer - that combined with some side load caused by the asymmetrical lower yoke mount was what broke my larger diameter Icon shock rod.

I always thought there was a small spongy bump stop inside the shock body to reduce the impulse load on extension. We're certainly running with heavier tires/wheels than Bilstein ever thought would go on this platform. Could you disassemble the shock to look for internal bump stops? For compression, we have the obvious orange foam external bump stop.

If there's nothing inside the shocks, we will all have to install limit straps.

[v7guy]

I'm going to be up most of the night so I figured I would take comparative pics and cut open the shock body with a 4.5 grinder and have a look around inside. There's no other obvious method to open it up. I could get pics of the shock internals while I'm giving it the once over. If there's any other pictures from this failure you guys would like to see let me know

[JMHinAZ]

Jason, appreciate your post, just installed the same setup but have the 88's instead so I'm keenly interested to see what else you find.

[JCrayton99]

If there's nothing inside the shocks, we will all have to install limit straps.

Since seeing the limiting strap instead of a sway bar in the rear I have been toying with doing the same in the front. I just need to get a measurement of our max droop from a fixed point on the frame...

[v7guy]

camera died before shock pictures, but I didn't see anything internally that appeared to be a bumpstop. I've got it charging up now, I'll snap the pics this afternoon.

[The Roadie]

Thx. The upper washer deflection is a big clue there's no bump stop in the shock. A bit less bushing damage than I was worried about. How many offroad miles do you think you had on them before the big hit?

I'm thinking some lube like silicone grease or a sheet of teflon membrane between the bushing and the aluminum might exclude other liquid and contamination. Might be that constant movement when there is a small amount of dirty water pooled in the bottom of the bushing cup ends up pumping the dirt into the aluminum-bushing interface. And that accelerates the wear on the upper bushing compared to the lower. Was the other bushing in your pics the lower, or the replacement? I'd be interested in side views of both of the bushings that came off the assembly.

A clear cover over the top of the spacer might keep contamination out and still allow for inspection. Even duct tape might be a good short term preventative measure.

Mark, Mike or JD - any ideas on a suitable lubricant for an aluminum->rubber interface?

The post-mortem of this incident is going to teach us all a LOT! That kind of stuff usually happens to me - thanks for taking one for the team!

[bartonmd]

The issue isn't really one of the lubricant for aluminum, but rather, a lubricant that doesn't collect dirt AND doesn't soften rubber.

I would think that some kind of a dry lube would be good. Graphite, maybe?

Mike

[v7guy]

Offroad miles... maybe 10. I've only wandered around in some wooded areas with sandy soil and a little rock a few times. You could probably double that if beach driving counts... I don't count the beach though. Other than that it's just been highway miles on some real bad highways for about 9 months. Nothing crazy at all.

The previous pictures was with the new rubber bushing next to the old upper rubber bushing. The upper is virtually worn through on on side. I assume from the uneven loading on it. Here's a pic of the lower bushing, it's in reasonably good condition as is the washer. Another of the upper bushing below it.







It looks like the tip of the shock shaft broke off right at the stamped X that locks the nut on... The threads in the nut are also pretty buggered but I'm sure some of that was caused by the shock shaft bouncing up and down in the guts. The parts of the shaft that broke off were easily identifiable when I opened up the shock. The bottom of the shock still had a decent charge of nitrogen in it and the seals inside the shaft seemed fine.








Other than that everything looked fine internally...








So I would wager the springs are probably one of the bigger culprits here. They added more lift, but top out the shock with more force than the lighter springs. Maybe a big piece of steel out front with a heavy winch on it would help. A lot of you guys were telling me that 9 months ago though. I would guess the washer slowly deforming helps save the shock and I'd probably still be driving around oblivious if I hadn't hit that repair.

I think I'm going to get a replacement washer for the passenger side and put everything back as it was. Then start working on a bumper. I've got the parts for the body lift here. So it seems best to move forward instead of swapping out to softer springs. do you guys think I would benefit any from lopping off a coil? As it stands with the spacer in there I can't hardly fit fingers between the coils.

[markmc]

The issue isn't really one of the lubricant for aluminum, but rather, a lubricant that doesn't collect dirt AND doesn't soften rubber.

I would think that some kind of a dry lube would be good. Graphite, maybe?

Mike

Graphite would be best..

By looking at the pics, it appears the rubber bushing has performed as expected in extreme conditions..
It saved the more expensive part (Aluminum spacer) from damage.
The shock however did not fair so well..

I really think the Moog springs, 88s or 89s might exert a little more pressure on the bushings than what they were designed for..
A higher duromat rated upper bushing would be the answer..if one could be found in that shape..

[v7guy]

Mark, do you think the a stiffer bushing would ultimately help or would it just change the failure mode to the washer and shock more quickly?

[The Roadie]

So no bump stop inside the shock for extension? And basically the nut tore off the shaft threads inside the shock body, and the external parts were all intact?

I double-nutted my shaft tops to make sure they didn't start loosening up, which also might increase strength due to more threads being engaged. But that won't help an internal nut tearing off its threads inside the shock body.

I guess we've been lucky so far, and limiting straps are the only robust cure I can think of. Certainly a stiffer upper bushing would be worse for the shock rod, and a softer one with more poofiness might be in order, to be a bump stop for the extension direction. Or a stiff Belleville washer or two. Like the existing washer, but meant to be deflected and recover. http://en.wikipedia.org/wiki/Belleville_washer

[v7guy]

Bill, that's correct.
There's no bump stop inside the shock. Effectively the upper shock bushing is the bump stop for extension. I suppose I could put some limiting straps on and link them to the sway bar attachment points but I can't imagine I have more than a half inch extension left on the suspension. I'm not sure where I would mount the upper part of the limiting strap but I'm sure I could figure something out.
I could also just hook up the sway bar, that would probably help. But I kinda like the truck without it.

[HARDTRAILZ]

Try the front hooked and rear disco. Works great for me.

[markmc]

Mark, do you think the a stiffer bushing would ultimately help or would it just change the failure mode to the washer and shock more quickly?

You have a good point.
Securing the upper end will more than likely cause the lower end to fail faster or possibly break the rod end at the weakest point just below the strut mount.

I would suggest reattaching the sway bar, It helps absorb and transfer stored spring energy from one side to the other..
Thats why the factory uses spring steel for the sway bar..
If you need more articulation for offroad adventures than i would suggest limit straps to prevent damage caused by over travel..

just my 2 cents..

[markmc]

I've got the parts for the body lift here.

Sorry for the double quote/post and offtopic
But i found a small issue on the rear body lift brackets i received from voltage.
The fab shop misslocated the welded on piece where the rear bumper gets relocated on the new brackets by about 1/2"
You wont notice the issue untill you go to remount the rear bumper cover..it wont line up..

Please send me a pic of your rear brackets to my gmail so i can confirm yours are correct or not..

[v7guy]

Actually, I pieced together a body lift with bolts and spacers from various sources in combination with a steering extension I bought from you last year. I figured I'd make my own brackets/ plate bumpers.

Guess I need to just make a decision and see where it takes me.

[Trail X]

I'm late to the game here... but the markings on the aluminum look very similar to the marks found on the outside of a brake edge of aluminum. Is it possible that the bushing mount surface is getting bent? If it's bending the steel washer, I'd imagine it's getting close to the force required to bend the aluminum too. Is that surface completely flat still? Hard to really get a good feel for it through the picture alone. Might just be an optical illusion.

What are the two rubber looking black cylinders? Are they shaft seals? Could they also be providing some cushion?

Mark, Mike or JD - any ideas on a suitable lubricant for an aluminum->rubber interface?

My first thought is to use the grease made specifically for brake pads. The heavy soap might keep most contaminants out. Not sure what the piston boots are on the calipers, but the grease doesn't seem to hurt them. Graphite wouldn't really keep anything out of the joint. If you really wanted to keep water out, you could do something as simple as putting a layer of plastic between the lift block and the frame bucket.

[JCrayton99]

I'm late to the game here... but the markings on the aluminum look very similar to the marks found on the outside of a brake edge of aluminum. Is it possible that the bushing mount surface is getting bent? If it's bending the steel washer, I'd imagine it's getting close to the force required to bend the aluminum too. Is that surface completely flat still? Hard to really get a good feel for it through the picture alone. Might just be an optical illusion.

It looks like that surface was being work hardened. If it was something thinner Id be worried about cracking, but on something that thick? eh...

[v7guy]

I'm late to the game here... but the markings on the aluminum look very similar to the marks found on the outside of a brake edge of aluminum. Is it possible that the bushing mount surface is getting bent? If it's bending the steel washer, I'd imagine it's getting close to the force required to bend the aluminum too. Is that surface completely flat still? Hard to really get a good feel for it through the picture alone. Might just be an optical illusion.

What are the two rubber looking black cylinders? Are they shaft seals? Could they also be providing some cushion?

Mark, Mike or JD - any ideas on a suitable lubricant for an aluminum->rubber interface?

My first thought is to use the grease made specifically for brake pads. The heavy soap might keep most contaminants out. Not sure what the piston boots are on the calipers, but the grease doesn't seem to hurt them. Graphite wouldn't really keep anything out of the joint. If you really wanted to keep water out, you could do something as simple as putting a layer of plastic between the lift block and the frame bucket.

It didn't appear to be bent during disassembly. I'll see if I can fit a flat edge in the to determine if it is still flat. The two plastic pieces are just that, to rigid plastic pieces. They don't have any obvious ability to be compressed. I would be really surprised if they do anything other than crack if compressed.

[markmc]

Actually, I pieced together a body lift with bolts and spacers from various sources in combination with a steering extension I bought from you last year. I figured I'd make my own brackets/ plate bumpers.

oh yeah..DUH.. i foregot..my bad..

lemme know if you need any brackets..
i will have some available very soon..