Wobble in the rear @ 80+ mph

[99svtdlb]

I have a 99 cobra and when I get on it, the car wobbles/weaves in the rear at about 80+ mph as I accelerate. It gets worse as I go faster. What in the world would cause this? Could it just be a bushing? Something with the IRS? Thanks.

 

[Dan_Soprano]

I have a 99 cobra and when I get on it, the car wobbles/weaves in the rear at about 80+ mph as I accelerate. It gets dangerously worse as I go faster. What in the world would cause this? Could it just be a bushing? Something with the IRS? Any ways I can check without taking it to a shop? Thanks.

IRS is aligned wrong. Get it realigned. My friend with an 01 Cobra had the same problem.

 

[99svtdlb]

how much did that cost?... are you talking about the actual IRS being aligned or getting it caster/camber aligned for the wheels?

...where could I get this done?

 

[tomustang]

you have to call around and check, alot of places do 4-wheel alignments

 

[99svtdlb]

I just got my car aligned the other day actually and it did it before and after I got it aligned. What should I do?

When I drive it normally, it drives straight as a whistle. But when I get on it...it weaves in the rear at around 70-80mph.

 

[Kilgore Trout]

Go back to that alignment shop with a rottweiler, six molotov cocktails, and several loaded weapons

 

[99svtdlb]

Go back to that alignment shop with a rottweiler, six molotov cocktails, and several loaded weapons

just might have to consider that

 

[Dan_Soprano]

how much did that cost?... are you talking about the actual IRS being aligned or getting it caster/camber aligned for the wheels?

...where could I get this done?

damn, I'll have to ask my friend. I think it actually had to do with the rear caster/camber. You can also call the ford SVT line direct. There # is on www.svt.ford.com

 

[99svtdlb]

damn, I'll have to ask my friend. I think it actually had to do with the rear caster/camber. You can also call the ford SVT line direct. There # is on www.svt.ford.com

dan...let me know what your friend says because if it's simply the rear caster/camber, it should be a cheap fix. Thanks. I'm assuming that it just needs to be put back into the correct specifications.

 

[Dan_Soprano]

dan...let me know what your friend says because if it's simply the rear caster/camber, it should be a cheap fix. Thanks. I'm assuming that it just needs to be put back into the correct specifications.

I'm pretty sure that is what it is. I'll know tomorrow afternoon when I see him. I know the ford dealer he brought it to ended up calling SVT, and SVT told the dealer what had to be done.

 

[Mike97gt]

dan...let me know what your friend says because if it's simply the rear caster/camber, it should be a cheap fix. Thanks. I'm assuming that it just needs to be put back into the correct specifications.

i am going to let on a secret. a lot of times even when you pay for a 4 wheel alignment all you get is a frt end toe set.

toe and go it's the make money way. and most people will never notice the difference. put it this way I have never seen another tech i have worked with align the rear wheels on a 4 wheel alignment.

how do you think shops can get away with paying the tech 1.0 for a frt end and 1.3 or so for a 4 wheel alignment. if the tech did all the setting right he could spend more time than the shop payed him to do it.

most auto techs work on the flat rate system. in this system if the alignment pays 1.0 hour ( typical flat rate pay for a frt end align)and he spends a half hour on it he gets paid 1 hour. BUT if he spends 2 hours on it he gets paid 1 hour to do it.

the system sucks what can i say. but thats how the entire buisness works.

 

[d90212]

I just got my car aligned the other day actually and it did it before and after I got it aligned. What should I do?

When I drive it normally, it drives straight as a whistle. But when I get on it...it weaves in the rear and gets dangerously bad at around 70-80mph.

did you get a 2 wheel or 4 wheel alignment? if you got the 2 wheel alignment, theyll just ignore the rear specs

 

[99svtdlb]

did you get a 2 wheel or 4 wheel alignment? if you got the 2 wheel alignment, theyll just ignore the rear specs

i did get a four wheel alignment. Would the problem be the alignment even if the car drives straight when driving normally, but when you get on it at high speeds, it wobbles? Pretty crazy.

 

[d90212]

perhaps your feeling an imbalance in the wheels. swap the tires from front/rear. does the imbalance follow? this would follow as well if theres a bubble in the tread.

also you should have received a printout of your alignment, before and after printout. if the printout looks good, it would probably rule out the alignment and need to look at either the suspension tweaking under load, drivetrain, or rearend..

 

[Dan_Soprano]

I'm telling you............my buddies problem was, under hard acceleration, the ass end would wobble back and forth like a fish tail. it got worse with speed. Sound like your prob?

 

[tomustang]

could also be a bad motor mount

 

[Disturbed One]

perhaps your feeling an imbalance in the wheels. swap the tires from front/rear. does the imbalance follow? this would follow as well if theres a bubble in the tread.

also you should have received a printout of your alignment, before and after printout. if the printout looks good, it would probably rule out the alignment and need to look at either the suspension tweaking under load, drivetrain, or rearend..

Even if the print out is good for the alignment, I know a couple guys/tech's that were fired for doing a 4 wheel alignment just by adjusting the heads mounted to the wheels of the car.

If the alignment is ok, I'd be looking for something bent, broke, loose.... anything that could contribute to it. All the lugnuts tight on the rear wheels??? might seem silly but I've had people complain about a wobble the faster they go and when I go look at the vehicle there's 2 lugs missing, 2 holding on with 3-4 threads and 1 lug all the way down finger tight.

 

[99svtdlb]

All my lugnuts are tight and my tread is fine. I have 275x35x18s in the rear with 245x35x18s in the front. What did ford tell your buddy to do?

 

[d90212]

Even if the print out is good for the alignment, I know a couple guys/tech's that were fired for doing a 4 wheel alignment just by adjusting the heads mounted to the wheels of the car.

If the alignment is ok, I'd be looking for something bent, broke, loose.... anything that could contribute to it. All the lugnuts tight on the rear wheels??? might seem silly but I've had people complain about a wobble the faster they go and when I go look at the vehicle there's 2 lugs missing, 2 holding on with 3-4 threads and 1 lug all the way down finger tight.

about adjusting the heads.... i remember those in the days.... and those machines really suck at alignments. since we moved to the new shop. our shop got the newest and latest alignment machine. wireless. lazererless. all reflectors and cameras. setting toe that is actually straight is now a one adjustment process.. ill try and post a picture of it later.
View attachment 489523

 

[99svtdlb]

Dan...was this the problem with your buddy's 01 cobra?

btw..I just got rear tires and my belt was broken. unbelievable!