Popping sound from rear of car.

[91CoupeMike]

Any cracking or warping in the metal?

Also look for elongated mounting holes.

No not at all, I'll take another look tomorrow.

I sure hope the torque boxes aren't fubard.. They were flush with the body and didn't have play, so I don't understand.

It's the arm rocking from being "loose" in the mounting. Like I said it wasnt snug like the drivers side, it just slid right in. Both upper and lower on that side. The noise sounds like it's coming from the upper.

[91CoupeMike]

[91CoupeMike]

Update:

First thing this morning I went out and took the contol arm out, went over all the spot welds and looked for any gaps in between the layers on sheet metal and everything is in good shape, no cracks, bends or signs of fubar.

So I focused on why the control arm didn't fit snug, simple fix.. Just put the bolt and nut on there without the control arm and tighten.. Now the arm fits snug and I loaded the arms and cranked the shit out of them with a 1/2 inch 18inch breaker bar.. I'd say there are pretty damn tight.

So went for a test drive, and like before backing out of the garage and up and down the street it was fine, but as soon as I got to the lucky testing lot.. It pops in reverse and then again in forward but not as constant.. It's not everytime like before and it's a helluva lot quieter.

Now keep in mind the arm I'm using doesn't have a perfect bushing, it's got a crack in it. But out of the 6 I had to choose from it was the best.

Now here's another Theroy I had while wondering, the quad shocks are boiled over like a champ and I don't run any isolators in the rear springs. Could I be mistaking the coil moving around for this? The passenger side sits a bit higher so maybe that spring is a bit taller? Idk.. Just food for thought.

Sosoe.. Pm sent..

[FoxBodyNick]

I have a theroy as well...

[Mark Preus]

My 86 I had made popping noise like you are describing. It would also wheel hop sometimes. I changed the lower control arms to mega might jrs and it all went away. So I assume my bushings were wore out

[91CoupeMike]

I have a theroy as well...

Well ?

I'd order some new aftermarket arms but putting a poly bushing in the upper without them being welded is kind of scary to me.

[91CoupeMike]

My 86 I had made popping noise like you are describing. It would also wheel hop sometimes. I changed the lower control arms to mega might jrs and it all went away. So I assume my bushings were wore out

Mine has been wheel hopping every now and then, I replaced with stock lca with poly bushings but haven't done much driving since.

[Sleeper]

Check the u joints as well.

[91CoupeMike]

Check the u joints as well.

It's not the u joints. I'm 100% sure on that.

I can't really rule out a control arm issue because the one on there isn't perfect. Just seems weird that it doesn't do it 100% of the time. It did when I first started this, and it was loud!

Seems to do it when I hit bumps now too.

Anyone have any spring isolators for the rear?

[Exile]

Energy Suspension Rear Upper & Lower Spring Isolators - 4-6101G
http://www.summitracing.com/parts/ENS-4-6101G/

[91CoupeMike]

Ok so I put the control arms I got from sosoe in and they don't make any noise. I went out and beat on it, stopped and reverse-forward.. Semi launched it and no noise.

Then I went to back up and it made the damn sound again, but couldn't get it to happen again. This is frustrating. Lol.. It was very quiet and Almost not noticiable.

Hopefully it Doesn't happen again.

If it were the boxes then it would do it %100 of the time regardless of what control arm was in the car, I'm somewhat dumb founded unless it's the quad shocks not holding the pinion angle down and causing them to bind, but that would mean they actually do their job as a quad shock. Lol!

Any other suggestions on where to look? Could it be the coil springs moving around because of no iso?

Thanks dfwmustangs brothers..

[91CoupeMike]

And it's doing it again.

What gives?

[Sleeper]

Are you sure there is no slop in the mounting hole? Oblonged streched.

This shouldn't be that hard to figure out.

[91CoupeMike]

Are you sure there is no slop in the mounting hole? Oblonged streched.

This shouldn't be that hard to figure out.

Well Ive never done any suspension stuff before, so I'm learning as I go.

I don't think there was slop, I will look in a second.

How would I fix this?

[Sleeper]

It should be easy to spot a egg shaped hole. I hope you get it figured out man.