Rear end knock after Ironman lift

[jja]

I replaced the Ironman shocks with the OEM ones and I've been driving like this for almost 10 days now. No knocking whatsoever. Since I have the stock length Ironman shocks nothing else changes when I put the OEM ones in but the shocks. So it's gotta be the shocks. Either the shocks themselves are defective or there is some size difference. I can't find size difference though when comparing to the OEM.

krisP why did sleeving the bolt not work? You can't find foil thin enough?

 

[krisP]

I replaced the Ironman shocks with the OEM ones and I've been driving like this for almost 10 days now. No knocking whatsoever. Since I have the stock length Ironman shocks nothing else changes when I put the OEM ones in but the shocks. So it's gotta be the shocks. Either the shocks themselves are defective or there is some size difference. I can't find size difference though when comparing to the OEM.

krisP why did sleeving the bolt not work? You can't find foil thin enough?

i tried a bolt with shorter thread and then with a sleeve, it fit it just didn't take the knock away. Have less than 1000 miles on the new shocks and would hate to have to spend more money to replace them

 

[jja]

Well the only significant difference in dimensions between OEm and Ironman is the width of the upper outer ring. On both units the width of the inner tube (where the bolt goes) is 46mm but the width of the outer ring is 40mm on Ironman and 37mm on OEM. Which means that on each side the outer ring is 1.5mm closer to the body mounts on Ironman.

I wonder could the rubber bushing between the inner tube and the outer ring flex to the point where the outer ring will make contact with the upper mounts which would result in knocking? That's the only thing left I can think of.

 

[jeeptorino68]

i have what sounds like the same thing as you are describing, but it only happens on the most extreme of angles, steep angle drive ways, etc.
i thought i was hitting the bump stops though (rear) i am running the same ironman kit, with 2 hockey pucks in the rear for bumpstop extensions.

 

[jja]

Have you tried driving on cobblestones? Does it happen there?

 

[tthompson442]

I worked with my Ironman retailer and have come to a satisfactory resolution to my "knocking" noise in the rear suspension.

The Jeep dealer confirmed the knocking noise was coming from the shocks.

The first step was replacing my 1 yr old knocking shocks with new Ironman replacement rear shocks. (Ironman has a two year warranty.) The knocking persisted.

My retailer pressed Ironman for a refund. He was successful and is sending me a pair of OME rear shocks in thier stead. They are in the mail!

Kudos! To Marlin at JBA!

 

[krisP]

mine is also the shocks, noise goes away when shocks are removed or replaced with OE. Have yet to hear back from JBA

 

[tommudd]

Tom, haven't you also suggested that something has to be tightened with the wheels & tires under load, rather than up in the air - or was that vis versa? Would doing it the wrong way possibly produce some noise?

Yes anything with bushings like new UCAs etc , even rear lower control arms
Tightening them while hanging down preloads the bushing

 

[jja]

Well it looks like we have three confirmed cases of Ironman rear shocks knocking. So it looks like Ironman did poor job with designing and/or building KJ shocks. I really wish I'd seen a thread like this before buying.

I guess the thread should be made sticky. Hopefully this will protect other buyers from making the same mistake.

 

[jja]

Hey Tom, shouldn't this really be made sticky? It could potentially affect a large portion of the community I guess.

 

[tommudd]

Well it looks like we have three confirmed cases of Ironman rear shocks knocking. So it looks like Ironman did poor job with designing and/or building KJ shocks. I really wish I'd seen a thread like this before buying.

I guess the thread should be made sticky. Hopefully this will protect other buyers from making the same mistake.

Never was an issue before so thats the reason for no one every talking about it. :shrug:

 

[jja]

Yeah I also found nothing about such an issue when I did my research on Ironman before buying.

It is an issue now, though. Looks like Ironman released a defective batch of shocks. They might or might not fix it but still it's worth knowing by anybody considering buying their shocks.

So that's why it looks like a good idea to make this topic sticky. What do you think?

 

[Geof3]

I wonder if it is a valving issue? If the rebound damping is not adequate for the rate of the spring rebound the shock can effectively extend too fast, thus causing a knock at the top of the stroke. This is fairly common on moto forks if the damping is not appropriate for the terrain. Or, same thing on compression, though less likely as most higher end shocks have some sort of bump protection built in.

 

[krisP]

I wonder if it is a valving issue? If the rebound damping is not adequate for the rate of the spring rebound the shock can effectively extend too fast, thus causing a knock at the top of the stroke. This is fairly common on moto forks if the damping is not appropriate for the terrain. Or, same thing on compression, though less likely as most higher end shocks have some sort of bump protection built in.

from how i took it ironmans explanation, rebound dampening was the source of the noise

 

[featherlight]

I have an '07 with the standard length IronMan shocks and have had no "knocking" or noise issues whatsoever (have 6,000+ miles on them now). I'm somewhat surprised to hear that several people suddenly experienced this issue.

 

[krisP]

i have the extended shocks, not worried about it though... they still serve their purpose . Nothing the volume knob on the radio cant fix

 

[Adam Roby]

...Nothing the volume knob on the radio cant fix

You sound like my wife... anytime I have to use her car I cringe with all the sounds and when I ask... she cranks up the volume and says "what grinding noise?"

 

[krisP]

You sound like my wife... anytime I have to use her car I cringe with all the sounds and when I ask... she cranks up the volume and says "what grinding noise?"

haha it would be a different story if there was something mechanically wrong with them or any other part of the jeep, they still work great just make a noise when they cycle ( the shocks not wives ) and the it resonates through the unibody.

 

[Adam Roby]

My wife makes PLENTY of noise, and that resonates in my brain!

 

[profdlp]

...they still work great just make a noise when they cycle ( the shocks not wives )...

I'm glad you made that clear. :happy175: