Waferboy

A while back I posted details on some suspension choices that I was in the midst of trying to make (https://mustangforums.com/forum/susp...n-choices.html). I finally saved my pennies and put everything in... MM Panhard Bar, MM Torque Arm, Stifflers FIT system, UPR Adjustable LCA's and Eibach Shocks. With the changes, out went the UCA's and the Quad Shocks. I was giddy with excitement to drive this car.

At first it was all great, new Michelin's helped me stick to the road much better. New Flowmasters got me a better sound... but then I started hearing noises. Pops and clunks out of the back end that had me nervous. They started slowly but became a bit louder with time and now it's very annoying.

First up, new spring isolaters, BBK Poly Isolaters went in. Result=No Change
Next, Greased the LCA bushings. Result=No Change

I then came across many discussions around the Fox Body torque boxes. Clunks and pops from them and how they were a weak point in the Mustang suspension. I couldn't find and tears or rips in the metal so I got some Wild Rides Battle Boxes and Installed those. Result = No Change

I actually drilled through the torque boxes where two sheets of metal came together and dropped in some Grade 8 bolts with 100lbft of torque (you can see the two bolts in the first picture link below). Result = No change.

Welded in the Battle Boxes and Torque boxes inside the car and out. Result = No Change

Here's what I've got
https://mustangforums.com/forum/memb...nted-over.html
https://mustangforums.com/forum/memb...nted-over.html
https://mustangforums.com/forum/memb...ugh-floor.html

With a "Screwdriver Stethoscope" I can hear the popping coming through the 4 bolts that hold the battle box to the floor pan loud and clear. I'm convinced this noise is from the LCA attachment to the Torque Box.

What I can't do is find this noise while I'm under the car. I've lifted it and done all the "benchpressing" I can do but the noise in not there. This noise which is from both sides is only heard when driving the car.

This car has been on a lift at least 4 times, I've had a fair number of people look at things and not finding much. Oh, the bolts, yes they are tight. In the >75ftlb torque range. I have yet to find anything loose.

Anyone have any ideas? Again, I don't see any tears in the metal so could I assume that some spot welds have given up allowing the metal to move? Maybe there is some welding needed on the front side of the torque boxes? I've seen the pre-made torque boxes out there, "...just cut yours out and weld in these..." but I'm not into that. I've got a fairly stock engine with a bunch of upgrades under the car so I shouldn't need to cut large holes in my car just yet.

Any help or ideas are greatly appreciated.

Thanks!

wydopnthrtl

What you need is to have good leverage to rotate the rear end when on the lift. I mean like a 4ft bar that bolted to the rear end.
Make a pretty stout cheater bar that bolts to the rear cover or maybe to the shock bracket. Something that will allow you to rotate the rear end with the car on a lift. (to mimic hard acceleration or braking)

That ought to give you enough leverage to find it when its on a lift. From there you can loosen one bolt at a time to try and isolate it.

It very well might be the fit between the bolt OD and the LCA bushing ID. (even though the bolts are tight the bushing may be slipping / clunking when under hard loads)

mattdel

Wait wait wait... you say you removed your UCAs? You can't do that. Only part on a fox that is "removeable" from factory is quad shocks. UCA's are quite mandatory and extremely, EXTREMELY dangerous to run without.

Old Mustanger

No, he didn't REALLY remove the Upper Control Arms, did he? He said he did, but he must be mistaken, the rear end would have so much play in it that it really couldn't go down the road, could it? I am pretty sure it couldn't.

Waferboy

Well folks, as a matter of fact I did remove the UCA's. If you read around the installation of a Torque Arm and Panhard bar will allow this to happen.

Look over here https://mustangforums.com/forum/susp...ion-guide.html and take a gander at the details under Torque Arm. This suspension guide has excellent detail which even I can make sense out of.

I like the big cheater bar idea. I actually just came across a "Suspension Guru" here in the Portland, Or area and hopefully I can get him to take a gander at things on Thursday or Friday.

Either way, keep the ideas coming. This is still just driving me nuts!

Thanks!

Old Mustanger

Thank god, I totally missed the note on the Torque Arm!
Ya had us scared there for a moment!

With your suspension setup, you need input from Jazzer. He has the most experience (that I know of) with the components you are using and how they work together.

UPRSharad

UPR adjustable LCAs with spherical bearings? Are they new? Are the jam nuts tight?

Jazzer The Cat

I was gonna ask if the LCA's have a smaller hole than in the TB's or where the connect to the axle. This can be an issue going with a '94~'98 LCA in a '99~'04 model.

Just for giggles, can you confirm the bolt is snug through the mounts and LCA's?

Jazzer

Waferboy

Jazzer, I'm right there with your thoughts. I hope to have this car up in the air in the next day or two to check the bolts. Unfortunately for the tool and strength that I can muster these bolts for the LCA's at the Torque box end are too tight for me to loosen. The last time I was able to get them apart it took a breaker bar, strap and come-a-long to loosen them so they were tight. But when putting in the battle boxes I didn't pay enough attention to the bolt and hole to see if the hole had become bigger or something. I hope to get those details soon.

Thanks to everyone for their comments!

Waferboy

Jazzer, I finally found a mods guy and he and I went over this car quite a bit. He agrees the sounds I was hearing are from the torque boxes. He has the car up on stands now and at last check got the LCA's out and looking over the TB holes and LCA's he was feeling some slop.

I don't think I told you but the LCA's in the car are UPR's Chromally Adjustables with the Urethane on the axle end and Heim joint at the TB end. I didn't realize it at the time but there was a bolt kit that UPR offered as well. Wish I would have got those. Just looking at the internet now I see the OEM bolts are necked down in the middle. Larger OD at the bolt head and threaded end and thinner in the middle. If that's the case then that makes all the sense in the world why I'm hearing what I'm hearing. This was a big miss on my part. The Heim bolt on these LCA's is sitting right on the thin part of the bolt. Ugh...

Now things are adding up, I talked with my mechanic on the phone yesterday and noticing the slop he noted at least one of the holes on in the Torque box was a bit large and worn out. So his plan was to punch those holes out up to 1/2" (if I remember right) and put in solid Grade 8 bolts that are essentially shoulder bolts that fit snugly everywhere with no threads or thin spots around the Heim bolt.

I'm hoping to get the car back tomorrow... Man I hope this problem is fixed.