My 2013 Mustang GT has a pretty loud creak / squeak coming from the rear end that only seems to happen when going over speed bumps. It does not squeak when driving down the road regularly - only when going over speed bumps. Also the front does not squeak at all, only the rear.
In the past couple months I already replaced both rear tires, both rear lower control arms, both rear shocks with new top and bottom rubber bushings and installed a brand new 2013 BOSS 302 swaybar with end links (which obviously replaced all the associated swaybar bushings and end link bushings as well.)
There seems to be no difference in eliminating the rear end squeak when going over bumps before vs after installing all those parts. What else could be the culprit?
I did NOT grease or lube any of the new parts listed above before installing, EXCEPT for the lower control arms which I greased through the grease fittings that came on them with a grease gun. Are any of the other parts listed supposed to be greased, else they may make noise?
It seems like you’ve already pretty much eliminated the main suspects by your replacements. hmm … Do you ever hear this squeaking when you press down on the rear bumper in various directions with the car parked, engine off? What about when jacking the suspension’s parts or the rear bumper to unload the suspension ? My truck makes a faint sound from the front when going over bumps, caused by the springs. I verified the location by jacking various parts of the front suspension.
Have not tried pushing the bumper yet. What would it indicate if the bumper did/didn’t squeak when pushing?
Also I did notice the new shock bushings already look old, like discolored and cracked when I had the wheels off - after just 2 months…not sure if this indicates anything?
The swabar bushings should be lubed. The drop (end) links especially.
So if you greased the control arms, they must be polyurethane bushings. The sides of those bushings also need a little grease although what squeezed out is probably enough.
Start with the spray. You should be able to scoot the drop links side to side a bit to get the lube in. Are these poly bushings, too? Or rubber? Either way a little silicone snould help.
Will try. Just a random question, is jacking our car up by the control arms in the front/rear ok? As in, is it fine for everything mechanically and won’t cause damage? My car is lowered with sideskirts and it’s hard to fit the jack in certain spots
It is ok but I would rather have you jack from the pinch weld jack points instead. If your side skirts are factory, they will flex a LOT before any cracking occurs. With stock rocker skirts, I jack right under the door mirrors. Lifts both front and rear so stands can be placed under the pinch weld jack points.
The rear can also be jacked from the differential.
You might have tightened up the nuts/bolts that squeeze bushings while the back end was jacked up and the suspension was dangling. When the car is back on the ground, the bushings are twisted near their limit. Going over speed bumps is just too much for them.
Loosen those nuts/bolts, lower the car to the ground and drive around the block, maybe some speed bumps, then bring the nuts/bolts up to the correct torque. Any better?
I am pretty sure (but not 100%) that the BOSS 302 package rear sway bar came with Polyurethane bushings as most performance suspension parts/bushings do, because they are much stiffer and reduce flex more than standard rubber bushings (better handling), if so then they are known to squeak and require lubing while installing, not after being installed, unless zerk (grease) fittings are in place, but anywhere the bushing touches metal, lube it…
Or you can install Polygraphite (self lubricating) bushings and be done with it…
Most of the time the Polyurethane bushings come with little lube packets to lube the bushings with… I think Mustangman covered some of this also…
And also make sure to load your suspension (mentioned above) before final tightening everything, you can easily do this with the vehicle up on car ramps with everything snug, not tight, then bounce the vehicle to settle the suspension and then tighten/torque everything to it’s proper specs…
