bad clunk over bumps following front bilstein install

hadtomer

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hey guys

i just got my kj after a front strut install. for those who dont know my jeep - it has front ome 927- top plates and a jba ring between the fork and the shock - and kk forks. also has a subframe drop. After i checked with you guys i went for yellow bilsteins - 4600 and not the "lift bilsteins". I threw away my rancho rs 500s - crap.....

anyway - for months now i have a strange thud when i go over bumps. a loud one - honestly it seems that it has been there for ever!! so i dont know if we are talking months or more. the kj is not a daily driver. the thud does not happen on compression - it happens when the shocks extend.



so - new bilsteins installed - my mechanic calls me and he is like "man...it is bad" - so i go to my jeep garage and my mechanic hands me the keys- same thud. we check...double check. front JBA arms are fine. and my mechanic tells me that i simply have too much lift. now - i dont believe in too much lift...lol....but he takes the shock apart from the jeep (sorry...bad english) - and tells me "man...look...the strut is almost all the way open with your 927s - whenever you compress it- it is ok - but is is always almost fully open - of course you hear a thud and of course it took you 2 years and 8000 miles to tear the ranchos apart".

what can i do? well - my mechanic will take the jeep fro a few days , drive it a while without the front anti roll bar - maybe we got it all wrong, but we checked everything.

I am really running out of ideas here guys- the thud is terrible. i thought the ranchos were to blame. but the brand new bilsteins made things WORSE.

p"s: new jba ball joints. fresh from the box.

Ideas?
 
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profdlp

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I had a bad clunk when I first got my lift but mine went away after things settled in. Can you get us some pictures of what things look like?
 

hadtomer

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Its at the shop - so it will take a while. but anyway- it truly is something i cant understand- I have had this thing for 5 years. I have bolted and unbolted every nut and bolt. almost everything is re-built and JBA'd (lol) and still - always something new.
 

marjsyd

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hey guys

i just got my kj after a front strut install. for those who dont know my jeep - it has front ome 927- top plates and a jba ring between the fork and the shock - and kk forks. also has a subframe drop. After i checked with you guys i went for yellow bilsteins - 4600 and not the "lift bilsteins". I threw away my rancho rs 500s - crap.....

anyway - for months now i have a strange thud when i go over bumps. a loud one - honestly it seems that it has been there for ever!! so i dont know if we are talking months or more. the kj is not a daily driver. the thud does not happen on compression - it happens when the shocks extend.



so - new bilsteins installed - my mechanic calls me and he is like "man...it is bad" - so i go to my jeep garage and my mechanic hands me the keys- same thud. we check...double check. front JBA arms are fine. and my mechanic tells me that i simply have too much lift. now - i dont believe in too much lift...lol....but he takes the shock apart from the jeep (sorry...bad english) - and tells me "man...look...the strut is almost all the way open with your 927s - whenever you compress it- it is ok - but is is always almost fully open - of course you hear a thud and of course it took you 2 years and 8000 miles to tear the ranchos apart".

what can i do? well - my mechanic will take the jeep fro a few days , drive it a while without the front anti roll bar - maybe we got it all wrong, but we checked everything.

I am really running out of ideas here guys- the thud is terrible. i thought the ranchos were to blame. but the brand new bilsteins made things WORSE.

p"s: new jba ball joints. fresh from the box.

Ideas?
I had a big clunk and it was the rear yellow bump stops. They fell apart due to age, and when I replaced them the clunk went. Seems your is different though ...
 

J.C.

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hey guys

i just got my kj after a front strut install. for those who dont know my jeep - it has front ome 927- top plates and a jba ring between the fork and the shock - and kk forks. also has a subframe drop. After i checked with you guys i went for yellow bilsteins - 4600 and not the "lift bilsteins". I threw away my rancho rs 500s - crap.....

anyway - for months now i have a strange thud when i go over bumps. a loud one - honestly it seems that it has been there for ever!! so i dont know if we are talking months or more. the kj is not a daily driver. the thud does not happen on compression - it happens when the shocks extend.



so - new bilsteins installed - my mechanic calls me and he is like "man...it is bad" - so i go to my jeep garage and my mechanic hands me the keys- same thud. we check...double check. front JBA arms are fine. and my mechanic tells me that i simply have too much lift. now - i dont believe in too much lift...lol....but he takes the shock apart from the jeep (sorry...bad english) - and tells me "man...look...the strut is almost all the way open with your 927s - whenever you compress it- it is ok - but is is always almost fully open - of course you hear a thud and of course it took you 2 years and 8000 miles to tear the ranchos apart".

what can i do? well - my mechanic will take the jeep fro a few days , drive it a while without the front anti roll bar - maybe we got it all wrong, but we checked everything.

I am really running out of ideas here guys- the thud is terrible. i thought the ranchos were to blame. but the brand new bilsteins made things WORSE.

p"s: new jba ball joints. fresh from the box.

Ideas?
Have you ever replaced the ball joints in the lower control arm?

Mine have failed previously and caused a noise like you mention. New ball joints eliminated the noise.
I now have greaseable ball joints in the upper and lower control arms.
 

WheelNut

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If you jack up the front of the Jeep how much do the wheels droop before the tires leave the ground? What is the distance from the wheel center to fender flare with the vehicle on the ground and what is the wheel center to flare distance with the vehicle jacked up off the ground? Like Fnawesomeinc suggested it is possible that the shocks are topping out.
 

James Heaslip

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hey guys

i just got my kj after a front strut install. for those who dont know my jeep - it has front ome 927- top plates and a jba ring between the fork and the shock - and kk forks. also has a subframe drop. After i checked with you guys i went for yellow bilsteins - 4600 and not the "lift bilsteins". I threw away my rancho rs 500s - crap.....

anyway - for months now i have a strange thud when i go over bumps. a loud one - honestly it seems that it has been there for ever!! so i dont know if we are talking months or more. the kj is not a daily driver. the thud does not happen on compression - it happens when the shocks extend.



so - new bilsteins installed - my mechanic calls me and he is like "man...it is bad" - so i go to my jeep garage and my mechanic hands me the keys- same thud. we check...double check. front JBA arms are fine. and my mechanic tells me that i simply have too much lift. now - i dont believe in too much lift...lol....but he takes the shock apart from the jeep (sorry...bad english) - and tells me "man...look...the strut is almost all the way open with your 927s - whenever you compress it- it is ok - but is is always almost fully open - of course you hear a thud and of course it took you 2 years and 8000 miles to tear the ranchos apart".

what can i do? well - my mechanic will take the jeep fro a few days , drive it a while without the front anti roll bar - maybe we got it all wrong, but we checked everything.

I am really running out of ideas here guys- the thud is terrible. i thought the ranchos were to blame. but the brand new bilsteins made things WORSE.

p"s: new jba ball joints. fresh from the box.

Ideas?
Check the steering rack bushings. Turn the steering all the way to the right. While looking at the steering linkage on the right side, have someone rock the steering wheel. Then do the same for the left. I bet the rack is lovely.
 

hadtomer

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hello. jeep not back from the shop yet. as for the ball joints etc- everything is new- moog or JBA. steering rack bushes- 1 year ago replaced with creative steel units. re-tightened.

bumpstops- terraflex extended ones- are still there.

I havent had a chance to jack the jeep up yet cause i dont have it with me.

But the one thing i cant understand is how can a shock be topping out if it is a simple coil over shock design???. why would it suddenly be extended? what am i missing here? same lift, same springs. did i do something to suddenly load the OME's? are the bilstein 4600s shorter than what i had before?
 

WheelNut

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It is definitely possible the Bilsteins are a bit shorter than the Ranchos. This is hard to know because there isn't much information out there about what is actually inside a shock. There might be top out bumpers inside the shock and its possible that the Bilstein top out bumpers are smaller, or perhaps non-existent. The internal gas pressure of the shock might be significantly higher on the Bilstein as well, which would create a higher effective cumulative spring rate.

Did your mechanic install new spring pads? That would raise the ride height of the Jeep a little bit, which could make this problem worse.

I know you believe that there is no such thing as 'too much lift', but suspension does require the ability to droop a fair amount to function properly. The suspension needs to be able to extend down into holes, and to extend when the vehicle body rolls in a corner. Without this ability to extend or droop you will get various adverse effects on handling. You are going pretty far outside of the design parameters by lifting the suspension really close to its' maximum extension, so it is not surprising that there will be some issues to overcome. Not saying your Jeep won't work with a mega-max lift, but just be aware you are at the edge of what is possible.

Best solution: Mount a big steel bumper with a winch to lower the front end a bit! haha
 

hadtomer

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yup. wheelnut - you are right - and what you wrote does make a lot of sense.

of course i am aware that the jeep is not exactly stock. and of course there is "too much lift" - heck - it is just an IFS. the spring pads are old.

the thing that I cant understand is - there is quite a bit of droop in the suspension. the only thing changed really is the bilsteins. but i guess- as you correctly pointed, the bilsteins might be different.

If all else fails i will probably drop the front a bit - or maybe extend the shocks a bit


. though that is a last resort - i dont like messing with that kind of stuff and it will damage suspension up travel.
 

jeeptorino68

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Are all the control arms torqued to spec? If not, that can and will cause clunks
 

hadtomer

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after 3 terrible weeks- the clunk was detected using a gopro - its the UCA! as it turns out the UCA kept banging on the spring. lucky for me- a friend of mine had spacers made -so i got those asap and after the install the clunks went away.
 

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WheelNut

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Very ingenious method of diagnosis! Good to know you solved it. Nothing to do with the shocks topping out after all then. Does the handling feel different before and after the spacers?
 

duderz7

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after 3 terrible weeks- the clunk was detected using a gopro - its the UCA! as it turns out the UCA kept banging on the spring. lucky for me- a friend of mine had spacers made -so i got those asap and after the install the clunks went away.
I didn't know such things existed, I wonder how much good it would do ro just move ball joint from top mount to bottom mount on arm . I'm getting a bit of spring knocking myself.
 

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