IRS driving me completely insane!! (moaning/creaking - video inside)

[dutch]

I went under the car again last friday and fixed the cobra clunk by tightening the bolts in the aluminium diff bushings, they were very loose.
Also greased and retightened the top shock nuts and bushings in an attempt to get rid of the creaking and moaning.

checked and tightened everything under the car again and couldn't find anything out of the ordinary EXCEPT for the springs. Which seemed to be touching the sheetmetal in the wheelwell right here:

I couldn't even get a flathead screwdriver in between the metal and the spring, so I took a small chisel and hammer to create some room. Not much, but it was worth a try. If only, it made it worse.

I have to admit, I was creative with the ISO's for the springs as CJ pony sent me the wrong ones. So one side has a new OEM lower IRS isolator and a used upper from the SRA, the other side has a new OEM top IRS isolator on the bottom and again a used one up top from the SRA.

Today comming home from work the noise became unbearable so I ripped out the linings, dropped the backseats and crawled in the trunk to try and locate the sound while my GF drove around the neighbourhood. It's def NOT the top-shock nuts or the bolts that I drilled into the trunk securing the IRS brackets. It's comming from underneath the car and is VERY audible both inside and outside the car. Occuring mostly on uneven roads, and when braking/accelerating from a stop.

I made a crappy video with my phone inside the trunk if that helps:

[nomedia="http://www.youtube.com/watch?v=XQSNpZIuXiU"]YouTube - IRS moaning[/nomedia]

This is just driving around the neighbourhood on a brick street going 5mph.

please, what the heck could this be, it's driving me nuts and making me want to sell the car and get a corvette even though I love the way the IRS rides.

 

[Digital]

Did you tighten everything and double check you don't have any end play in anything including the actual frame mounts on the car?

 

[Jimmysidecarr]

Can you list the mods done that are rear suspension, rear drive line related for us.

 

[dutch]

Full delrin bushing kit in A-arms and subframe mounts, aluminium bushings in diff.
Stock Bilstein shocks, eibach IRS springs with weird ass iso combination as mentioned above. 14mm bolts in front mounts and new MM low profile ones in the rear.

I suspect a moving part in the suspension, but the weird thing is that it's not comming from one def side of the car..
It even makes the noise when I get out of the car and the suspension moves a little bit. I can open the trunk and push down on the floor and make it squeak a little.

 

[arc00ta]

Wow my car makes that same noise, both in the front AND the back. It sounds like an angry pogo stick. All my stuff is stock though. Curious to see what it will be, I thought it was just worn out rubber bushings so I didn't worry because I'll be replacing them soon.

 

[SlowSVT]

Man the noise in your vid sounds like a hammer rattling around inside a wooden barrel.

A loose bolt may have hammered an elongation in a bolt hole. Worn IRS spindle hiem joint, loose wheel bearings, bad CV joint, exhaust hitting undercarriage, loose fuel tank strap, bad A-arm bushing (do they have grease joints). Removing the springs may help to isolate the problem exposing a loose joint :shrug:

Just throw'N out some possibilities.

 

[SlowSVT]

Digital

Something tells me this part was the foundation for your car and you just worked "up" and "forward" from there :nonono:

 

[Jimmysidecarr]

There is a high probability that the surfaces of the ears that the upper control arms mount to may be making the noise.

These should be cleaned and smoothed and made parallel to the bushing ends.
They may also need to have a heavily greased shimming washer installed so that there is more than one rotating surface where the control arm pivots.

Instead of taking it apart I would first try to get some grease into the ends of each of your pivot points.

If that does not work have someone move the car up and down while someone inspects the location of the exact noise source. This may involve driving onto stable boards to allow higher ground clearance yet a still loaded suspension.

It will likely be control arm pivot points that are too dry.

 

[03Snake04]

Did you tighten everything and double check you don't have any end play in anything including the actual frame mounts on the car?

i like where this is heading :thumbsup:

 

[ac427cobra]

Does the car make any noise when you bounce it while it is sitting? If so get it up a little and have a friend bounce it for you while you get under it and look/feel for the source of the noise.

 

[Digital]

Digital

Something tells me this part was the foundation for your car and you just worked "up" and "forward" from there :nonono:

Ya ya lol. I mean the SRA muffler attachment points are still there. It's like it was meant to be! lol.

There is a high probability that the surfaces of the ears that the upper control arms mount to may be making the noise.

These should be cleaned and smoothed and made parallel to the bushing ends.
They may also need to have a heavily greased shimming washer installed so that there is more than one rotating surface where the control arm pivots.

Instead of taking it apart I would first try to get some grease into the ends of each of your pivot points.

If that does not work have someone move the car up and down while someone inspects the location of the exact noise source. This may involve driving onto stable boards to allow higher ground clearance yet a still loaded suspension.

It will likely be control arm pivot points that are too dry.

+1 it sounds a lot like a loose item. That or a bushing is decaying and crunching on itself.
I'd really try to get someone in the trunk while moving and pinpoint it, possibly even drive close to your head slowely while someone bounces it so you can listen. I've done some crazy stuff to pinpoint sounds. Gotta get creative.

 

[dutch]

Thanks, I'm putting it on a lift in a local garage this saturday so the suspension is loaded and I can yank the subframe to make it bounce and check everything.

 

[THE EVIL TW1N]

Thanks, I'm putting it on a lift in a local garage this saturday so the suspension is loaded and I can yank the subframe to make it bounce and check everything.

I know 100% what your problem is. Mine makes the same exact noise. You need to shoot (and I mean really SOAK) ALL the IRS (delrin) bushings with some WD40. I have tried about 10 different "lubricants" (some of them pretty expensive) on it and I have found that WD40 of all things works the best. I have to do this approximately every 6 months or so, depending on how long I can take the creaking. Remember, you really have to shoot a bunch of WD40 on there. When you think you've shot enough, shoot twice as much more. Then, you have shot enough.

Im surprised you didn't have a different suggestion ac427cobra, you're the one that helped me out with it before (i have your older delrin bushings kit without the grease fittings) :beer: I was pulling my hair out there for a while and thought I made the mistake of not going SRA. :fart:

 

[THE EVIL TW1N]

btw, when I have to do this, I just put the car on jackstands and spray away.

 

[dutch]

Thanks a lot, will def give that a try!

I was under the impression that Delrin didn't make any noise, that's why I'm looking in the direction of springs/shocks/etc.

I think I have the older bushings as well, from what I read the bushings were even in the car when the previous owner got it.

 

[Quick Strike]

I think I have the older bushings as well, from what I read the bushings were even in the car when the previous owner got it.

Maybe this is it!

 

[Digital]

I know 100% what your problem is. Mine makes the same exact noise. You need to shoot (and I mean really SOAK) ALL the IRS (delrin) bushings with some WD40. I have tried about 10 different "lubricants" (some of them pretty expensive) on it and I have found that WD40 of all things works the best. I have to do this approximately every 6 months or so, depending on how long I can take the creaking. Remember, you really have to shoot a bunch of WD40 on there. When you think you've shot enough, shoot twice as much more. Then, you have shot enough.

Im surprised you didn't have a different suggestion ac427cobra, you're the one that helped me out with it before (i have your older delrin bushings kit without the grease fittings) :beer: I was pulling my hair out there for a while and thought I made the mistake of not going SRA. :fart:

oh man i'm restraining myself soooo much lol.

 

[dutch]

Don't think so Quick Strike, thanks for the heads up though. Silly thing is, the car actually drives really well! It's just making an aweful noise..

One other thing I noticed; Every picture of delrin bushings I see they're white..

My subrame mount bushings are white, the LCA bushings are black (not rubber) the upper arm ones are blue, en the diff bushings are aluminium.. what the!?

 

[ac427cobra]

Don't think so Quick Strike, thanks for the heads up though. Silly thing is, the car actually drives really well! It's just making an aweful noise..

One other thing I noticed; Every picture of delrin bushings I see they're white..

My subrame mount bushings are white, the LCA bushings are black (not rubber) the upper arm ones are blue, en the diff bushings are aluminium.. what the!?

Subframe bushings are white and they are UHMW.

LCA Delrin bushings are black. (normally)

Those teal UCA bushings are an early version of our Delrin UCA set.

Rear diff is both Delrin AND aluminum.

I would think it would be pretty easy to tell the difference between a bushing squeak and a knocking or banging sound. :shrug: Yes the early bushings without grease fittings can and do squeak after a while and a good synthetic penetrating spray lube can quiet them down. Many times the squeaking can come from the Delrin rubbing on the paint of the subframe and that is why we recommend removal ALL paint in areas the Delrin is making contact.

Hope that helps.

:thumbsup::coolman::beer:

 

[THE_EVIL_TW1N]

Subframe bushings are white and they are UHMW.

LCA Delrin bushings are black. (normally)

Those teal UCA bushings are an early version of our Delrin UCA set.

Rear diff is both Delrin AND aluminum.

I would think it would be pretty easy to tell the difference between a bushing squeak and a knocking or banging sound. :shrug: Yes the early bushings without grease fittings can and do squeak after a while and a good synthetic penetrating spray lube can quiet them down. Many times the squeaking can come from the Delrin rubbing on the paint of the subframe and that is why we recommend removal ALL paint in areas the Delrin is making contact.

Hope that helps.

:thumbsup::coolman::beer:

I didn't hear any banging or knocking sound on the video. Maybe I'm not hearing it the same.

Right now, my car is squeakng something awful lol I haven't had the time to get under it and spray some WD40 on it this winter yet. Maybe I'll record some before and after sounds to verify with the OP.