My Car Has A Wiggly Ass... Why?

[don_w]

OK, here are the symptoms. When cruising down the highway, say 65mph, and I give it just a little pedal (like passing, changing lanes, etc), the car lurches to the side. Usually it pushes the front to the right (or rear goes to the left), but every so often it does the opposite. And under full throttle or at lower speeds, I don't ususally feel it doing it.

At first, we thought it was the M&H drag radials. They were 3 years old and pretty used up. So I bought new ones. No change in the wiggly ass. In fact, it now seems to get a little worse each day. It's getting to the point where it is downright scary at times. I really need to figure out what's going on before I put this thing into a K-rail.

I'm hoping to get it up on jackstands this weekend and take a close look at the suspension parts. Maybe there is something loose. But, I don't hear any unusual noises at all.

If it isn't the suspension, could it be the Detroit Locker? It has the typical "clunk" of a locker, but could the unlock/lock process get that severe such that it moves the whole car sideways? And would it get worse over time?

Finally... what else could be causing it? Any and all thoughts appreciated...

FYI... This is my set up:

REAR END
FRPP 4.10 Gears, 8.8”
Detroit Locker Differential
Powerhouse Aluminum Driveshaft
BMR Driveshaft Loop
Moser 31-spline Axles, 3” Studs
Moser Rear End Girdle

SUSPENSION Ford Cobra Jet Rear Springs
BMR Tubular K-member
BMR Radiator Support/Sway Bar Delete
BMR Adjustable Lower Control Arms
BMR Adjustable Panhard Rod
BMR Panhard Relocation Bracket
BMR Adjustable Upper Control Arm
BMR Extreme Anti-Roll Bar
Steeda Lower Control Arm Relocation Brackets
Spohn Rear UCA Housing Bushing Kit
Calvert Shocks

 

[AbdullaGT500]

Mine did this once, my LCA relocation brackets were loose.
I had them welded up and problem solved.

 

[JEWC_Motorsports]

I was thinking maybe worn bushings in the lcas.

 

[retfr8flyr]

+1 on the bushings, if you have poly bushings you could have compressed one of them so that it moves some during acceleration. If I remember correctly your LCA relocation brackets are welded. Could also be one of you front control arms causing it.


Earl

 

[BlackSunshine]

Maybe the adj pan hard nuts came loose? If it's not locating the rearend properly and its moving side to side, might cause that type of issue. Should be easy to check that real quick just looking underneath at the adjustable nuts.

 

[psfracer]

If it does it all the time then check for a bent relo bracket. If only while under acceleration then check for a damaged bushing which allows the rearend to move while accelerating.

 

[frank s]

Seems like a rear-axle-steering problem: in the olden days a recommendation to tighten the U-bolts would solve it. What is the equivalent action for coil-sprung axles? Whatever it is, the idea is to stop the axle from rotating when power loads change.

 

[dysan]

Mine has this symptom a little once I put the locker in it. It will do that when I either get on it or when in power let off and the locker either engages or disengages.

Also, mine was squirrely when the bushing on top of the diff was shot.

 

[don_w]

Thanks, guys. My relo brackets are welded, and some locations are Heim joints. I'll definitely take a look at the bushings that aren't metal. Hopefully the problem will be obvious and easily corrected.

 

[don_w]

Good news / bad news. Good news is nothing seemed unusual with the suspension underneath the car. Bad news is I haven't found the problem.

 

[frarmar]

I'm with ya man... Mine only did it with DR's on too, most noticeably with the 15" wheels. Never did find the problem.

So I guess I'm no help... lol

http://s197forum.com/forum/showthread.php?t=44842

 

[kwiksilver]

It's the detroit. All the 4x4's that I have had with detroits do that. It lockes one side a split second later the other and does the "wiggle" just get used to it.

 

[05mustang_TT_charged]

Take a measurement between the passenger side front and rear wheel centers and drivers side. I had a LCA get out of adjustment and mine did the same thing. I also thought it was a bent relocation bracket and they looked straight. Didn't find the LCA problem till we had car on 4 wheel alignment machine.

Also welcome back stranger.

 

[Speed+Clinic]

Try the diff bushing its only like 30 bucks

 

[Boozshey]

Spyder gears...

 

[05mustang_TT_charged]

Spyder gears...

Doesn't have any. He has a Detroit Locker.

 

[Boozshey]

Axle gears?

 

[don_w]

It's the detroit. All the 4x4's that I have had with detroits do that. It lockes one side a split second later the other and does the "wiggle" just get used to it.

But it also seems to be getting worse. And it doesn't do it as much at low speeds vs highway speeds.

Take a measurement between the passenger side front and rear wheel centers and drivers side. I had a LCA get out of adjustment and mine did the same thing. I also thought it was a bent relocation bracket and they looked straight. Didn't find the LCA problem till we had car on 4 wheel alignment machine.

Also welcome back stranger.

I'll check that out...

... and thanks!

 

[Mustang30212]

My old fox body did that...it was broken welds in the torque boxes.

Not sure if it applies to the S197 platform or not.

RH

 

[kwiksilver]

rig a hose to equalise the air pressure in both tires (2 chucks with a long hose will work) You might have unequal air pressure making one tire larger than the other. The wierd thing is that it switches directions. I agree about the lca bushings. Being a 3 link, one bushing could cause the rear to lurch.