I have read all of the "rear suspension squeak" threads

But still can't figure out what is causing mine. Only starts squeaking/creaking after the car has been driven for at least 15 minutes or so and then it squeaks like crazy over smaller pavement imperfections (big dips or undulations don't make the noise). And it has gotten worse recently. Front suspension is completely quiet but once the rear compresses a fraction of an inch on either side, it makes the noise. I could literally drive over something small like a pencil and it would go SQUEAK. The noise is not affected by being in gear or not, or having the brakes on or not.

Here are the facts:

2013 Boss 302 with 12k miles (owned since new) - Has brand new Whiteline adjustable LCAs along with WL relos, stock UCA (only a few thousand miles on it - see below), Fays2 alloy Watts link, GT500 rear discs and ebay brake relocation bracket, KW V3 adjustable rear springs and SR Performance shocks, 18mm rear swaybay with brand new OE endlinks and Prothane bushings at the ends.

I used to have Steeda billet alloy LCA (with Heim joints), Steeda UCA (the one made for lowered cars) and bracket, KW V3 shocks, OE swaybar and bushings but I started swapping things out in an attempt to fix the squeaking.

The squeaking is absurd and really makes me not want to drive the car. I have tightened all of the exhaust clamps and even replaced the axleback exhaust hangers. I have spent Lord knows how many hours underneath the car tightening, yanking, pulling, pushing everything and still have no clue.

Any additional direction would be greatly appreciated, guys. I have a feeling it is something simple. Thank you!

John

Key piece of info... no noise until driving after 15 minutes. That means something is heating up, expanding and causing the noise. Likely on the exhaust system. Check all of the muffler hangers again, specifically the ones on the rear pointing towards the bumper. Look on the bumper for any evidence of rubbing. My guess is that a hanger is rubbing against the rear bumper.

When did it start exactly? What mods did you do when it started?

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My money is on the rear sway bar bushings being dry. You might need to remove them and grease them up.

Did you tighten the everything with the suspension loaded? What grease did you use?

Unless you install rubber, you don't have to load the suspension. BMR specifically annotates (and has told me verbally when I did my install) that poly mounts do not require the suspension to be loaded.

Hey guys thank you for the replies!

1) it started several years ago but was just an occasional squeak here and there. It had the Steeda LCAs and UCA, WL relos, and KWs at the time. Watts link came later;

2) rear swaybar has brand new bushings and endlinks (literally brand new this weekend), lubed up with the silicon lube provided by Prothane (I even put it on the endlinks rubber);

3) It has made this noise with all 3 of the following axlebacks: GT500, FRPP Touring, now Borla S-Types. I will quadruple check all of the clamps and hangers.

4) Suspension was loaded when control arms were installed, except the UCA because there is no way to do that without having the suspension drooped all the way down (at least not for an amateur mechanic like myself!).

I'm going to drive it and get the noise going good, then immediately jack it up and see if I can recreate it in my garage. My city is being shut down so I should have some time in the next few days to spend some more time staring at the underside of my car.

accidental double post

1950StangJump$ said:

Unless you install rubber, you don't have to load the suspension. BMR specifically annotates (and has told me verbally when I did my install) that poly mounts do not require the suspension to be loaded.

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They have always said the suspension must be loaded, even their vids.

Probably uca since it wasn't torqued down loaded.

I would love to hear the technique of how to properly torque the UCA with the suspension loaded. I can't get a wrench in there without the axle being down. I am contemplating taking the whole rear end back apart anyway.

Ah ok I see what you mean - yes, I installed the diff side bolt on both the Steeda and OE UCAs with the axle loaded and not drooped.

I was thinking about the other end of the UCA where it mounts to the chassis bracket - there is pretty much no way for me to tighten it to spec once it's bolted on the car with the axle under full load because it's so tight in there.

Update: installed Ford Racing K rear springs and new upper and lower isolators. Took it for a drive, and the squeak came back after 15mins. The next day, I drove it for 45 minutes and it was completely silent but I still took it my favorite Mustang shop to examine. They thought it might be the flag nuts on the lower shock mount rubbing on the shock itself so they pried them a fraction of an inch away. Drove the car home (only about 10 minutes in the rain) and it was silent. Because I am an idiot and did not like how soft and low the Ks are (hit the bumpstop a couple of times in just a few miles), I went ahead and reinstalled the KW springs. SQUEAK SQUEAK SQUEAK! So maybe it is the KW springs and adjustable perch after all?? But why were the Ford Racing Ks squeaking the 1st day and then silent after that??

Another update from today: removed rear swaybar altogether. Drove around. Squeak squeak squeak. Ordered P springs and new isolators. If this doesn't work, I will removed my Watts link.

Do those LCAs have poly bushings on the body side? That's what was causing an infernal squeak on mine no matter how much they were greased. Opted for some Edelbrock adjustable LCAs and has been quiet ever since.

Never mind...saw where you swapped LCAs.

Yes LCAs have been swapped - good idea, though!

BTW - I love the way your car looks, Bingo! Are those the Saleen wheels?

Champale said:

Yes LCAs have been swapped - good idea, though!

BTW - I love the way your car looks, Bingo! Are those the Saleen wheels?

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Thank you. Yes, they're the Saleen Heritage wheels. Good luck with the squeak; I know how annoying that can be.

I freaking love those wheels! I have dreams about buying another 05-14 Mustang and putting those wheels on it.

I think it's fixed! Swapped rear springs for FRPP P springs and new isolators, disconnected the UCA at the diff then reinstalled, noticed one of the O-rings on my Fays2 Watts link was cut, sprayed WD40 over the heim joints, and removed the factory air compressor kit from the trunk, reinstalled rear swaybar. Have taken 2 separate hour+ long drives and the suspension has not been making the squeaking or any clunking. Fingers crossed.