Cobra Out of control!!! HELP!

[TerminatorTom]

So I recently purchased an 04' Cobra vert. Runs great and was extremely well taken care of, but of course, still has the dreaded "COBRA CLUNK". But on top of that, there is a way more significant problem

When I'm driving, if i press on or let off the throttle, not only do i get the patented "clunk", the car steers itself left or right depending on accel or decel. This problem becomes VERY apparent at highway speeds. Everyone who has been in the car with me has felt like I'm just swerving back and forth.

And i can reproduce these results by simply letting off the gas every single time. It feels like the rear is literally steering itself.

I know for sure this has something to with the rear end being put under an acceleration/deceleration load because if i put the car in neutral and coast, there is no sign of this problem at all......

So if anyone has had this problem or has an idea on how to fix, your input is GREATLY appreciated.

Thanks Guys

 

[stangaholic280]

Why not start with the basics first? Have you taken it to be aligned and balanced? Could solve your steering problem right there.

Does it have aftermarket headers, if so your clunk could be a bad gasket...I know I thought I had the dreaded head tick and all it was was an exhaust leak.

 

[2000gator]

My cross axis joints were bad in my car and it caused it to wander a good bit. I replaced them and it feels much tighter now. Not sure if thats your problem but they are located on the top and bottom of the knuckle. Easy to inspect just check for play with the wheel on or off. This was on a 99 irs

 

[TerminatorTom]

Just for Clarification, It feels like the rear end that is steering. I feel nothing at all in the steering wheel, but i have to correct it or I'll drive off the road. So im pretty sure it has something to do with the IRS, just not sure what

 

[Slow99x]

If you feel that your rear end is causing your out of control feeling then your rear wheel bearings are going bad. I had this same problem and a new set fixed it. You might want to talk to Bruce from fulltiltboogie. He sold me the entire knuckle assembly for the same price as shops wanted for just the bearings.

 

[racebronco2]

I would guess the wheel bearing also.

 

[Unitek]

Crazy someone just posted this. My buddy just bought a 04 and the car on the highway steers all over the place at crusing speed of 55mph, like almost out of control dangerous. WOT the car fish tails and on decel it gets into even worse fish tail. The car doesn't clunk at all, it just feels like its driving on flat tires. anyone got any ideas ?

 

[ac427cobra]

Crazy someone just posted this. My buddy just bought a 04 and the car on the highway steers all over the place at crusing speed of 55mph, like almost out of control dangerous. WOT the car fish tails and on decel it gets into even worse fish tail. The car doesn't clunk at all, it just feels like its driving on flat tires. anyone got any ideas ?

9 times out of 10 this is caused by a halfshaft retaining nut that has worked loose. When the car is run in this condition it causes the bearing to self destruct. If left to run long enough like that it will eventually destroy the hub as well. The hubs at your friendly Ford dealer now list for almost $300 EACH! That's not the knuckle assembly, those list for over $600.

FWIW

:thumbsup::coolman::beer:

 

[skratpiece]

WHEEL BEARING!. Mine was the left rear. Caused the car to feel like ruts were pulling it all over the road. There is a complete rebuild video somewhere out there. This is just a little piece I found from a quick youtube search. Ford replaced mine under warranty. This may explain to you what's going on. [nomedia="http://www.youtube.com/watch?v=s1CqCFJVKNU"]YouTube - Cobra IRS Hub and Bearing RR[/nomedia]

 

[TerminatorTom]

So if it is a bearing or halfshaft, would that mean it would only feel like that under a load? If I'm doin 70 or so and put it in neutral and coast, the problem is completely eliminated

if it is one of those two things... What could I look for under the car? Or are there any other symptoms

 

[ac427cobra]

So if it is a bearing or halfshaft, would that mean it would only feel like that under a load? If I'm doin 70 or so and put it in neutral and coast, the problem is completely eliminated

if it is one of those two things... What could I look for under the car? Or are there any other symptoms

It would happen any time it's loaded or unloaded with power or steering.

Best thing to do is jack up the rear of the car and feel the rear wheels for play. Wiggle them at the 12 and 6 O-clock positions and again at the 9 and 3 O-clock positions.

FWIW

:thumbsup::coolman::beer:

 

[TerminatorTom]

Well if I am coasting in neutral, there are no problems even when turning.
It actually feels pretty decent. But as soon as I'm on the throttle, no es bueno.

I just drove home from work and this is all bad. Like borderline dangerous.

But I'm about to get under the car right now.

Will update on wheel play and anything strange....

 

[ac427cobra]

Well if I am coasting in neutral, there are no problems even when turning.
It actually feels pretty decent. But as soon as I'm on the throttle, no es bueno.

I just drove home from work and this is all bad. Like borderline dangerous.

But I'm about to get under the car right now.

Will update on wheel play and anything strange....

If it is in fact a wheel bearing it will feel unstable if you change lanes at a brisk pace on the freeway.

Jacking up the car and feeling the tire for play is going to be your first check.

:thumbsup::coolman::beer:

 

[TerminatorTom]

Ok, so bad news is my jack is missing. BUT, i do have ramps and was able to get under the car and tinker around. I what i found seems somewhat disturbing to me:
If I push/pull on what Im guessing is a damper on the bottom of the diff, it moves EXTREMELY EASY, which in turn is able create a bunch of space between the subframe and the bushing in the two bolts above it. This is moving the entire diff and I'm able to do it BY HAND!

Something seems wrong here....

 

[ac427cobra]

Ok, so bad news is my jack is missing. BUT, i do have ramps and was able to get under the car and tinker around. I what i found seems somewhat disturbing to me:
If I push/pull on what Im guessing is a damper on the bottom of the diff, it moves EXTREMELY EASY, which in turn is able create a bunch of space between the subframe and the bushing in the two bolts above it. This is moving the entire diff and I'm able to do it BY HAND!

Something seems wrong here....

If the differential mounts are shot, that is very common. This is one of the main contributors of the Cobra clunk. You should not be able to move the differential by hand AT ALL!!

FWIW

 

[TerminatorTom]

Yea its not even difficult to do. I can move it far enough to smack part of the irs subframe thats in front of it and that actually sounds like my clunk. Looks like i have to get the exhaust off to really get to those bushings...

Are those just the front diff bushings?

 

[3Dglasses]

Loose rear toe links can also cause this sensation, but it sounds like you found the issue...

 

[TerminatorTom]

Ok, So i thought it was just the diff bushings.... wrong....
While that eliminated a lot of my "clunk", the problem persisted, but this time luckily i had a jack.
So it seems like the inner tie rod bushing is shot and moving all about... If thats what it is anyway... So im on the hunt for the part but cant seem to find it anywhere besides for who wants to charge a grip for it...
Any suggestions

 

[1wild-horse]

buy bruces (ac427cobra)toe link upgrade kit, you'll be happeir with that over the stock pieces anyway. change both sides and get rid of the weak ass links under there.

 

[Teej281]

Buy a new tie rod kit from Bruce. His kit is awesome. Its on my car and its a solid piece. I just need to get it all adjusted now.