I'm hoping that this may just need a front end bushing, ball joint and tie rod replace, but it may be more? Tonight, I finally got to drive my 93 GT to Huntsville, after nearly 2 months of repairs. Anyway, noticed the vibrations to be the worse at any speed over 65. Vibrations felt like they started in the rear, but the steering wheel shakes really, really bad and the car rides so much more rough at 65+ Does anyone know what may be the problem? I thought about wheels off balance, but if it was that, wouldn't it vibrate all the time?

 

What sort of repairs?
Could just be out of balance tires though.

 

tires would cause vibration at higher speeds if it's not far off....

other possibilities.

driveshaft
wheel bearings
rotors (yes it can cause a vibration)
incorrect pinion angle on the drive shaft
tires being oddly worn (could be tread seperation on one or more tires)
tires could also be slightly worn caused from the following 2:
-bad shocks (yes it could fugg it up)
-alignment out of whack
could be alot of things, it's all about trouble shooting....

 

Well, another thing I forgot to add. The front tires are a different size than the rear and it also has 3 different brand tires on it and let's just say they aren't new, but look like they have decent tread left...?

 

ok...change those first....if it's a fox, I believe the correct tire size is 225 60 16

 

Like replacing the tie rods(inner/outer), ball joints, wheel bearings, steering rack bushings, sway bar/endlink bushings, etc. I planned to replace all this crap in the fall of this year. Then, I was planning to buy some of those 17" Pony R's, some 245/40 and then gettin the alignment and hope after I fixed everything, that there won't be any vibrations afterwards? The car is all original, with 130K miles on it and nothings ever been replace, that I can tell, except the oil, plug wires, plugs and air filter.... oh and the mismatched tires

 

don't forget to flush your cooling system (actually flush it, don't just run water through it) change your thermostat out (put a 180 in) change your diff fluid don't forget to check for metal shavings and also don't forget the friction modifier, change the tranny fluid out, I reccommend royal purple syncromesh. check driveshaft for play (shouldn't wiggle at all)

change your brake fluid out with a real good bleed job starting with the back. bleed mastercylinder if you can. all new dot3 or dot 4 fluid
flush out power steering with new, some shops have special tools to do this correctly, car will feel great afterwards.

these are all things I would do to a car that old that wasn't exactly taken the best care of.....

 

Well, all that's gonna take a while, because I'm not made outta money and this is a toy, not a daily driver. Already flushed the cooling system, changed out the WP and thermo. About to do a fresh tune up today, because a couple of the old plug wires are almost burned into

 

Sounds like some front end problems. Tires would be the cheapest and easiest fix. Probably something in the front suspension.

Just dont take it to Firestone, they will tell you that your car needs $15,000 in repairs and that its not safe to drive.

 

ya, don't listen to normal repair places.....most will gip you. my dealership has done all the work I've needed to any car including my cobra if it was something I was incapable of. I normally know people local to me to do all kind of repairs, don't get too upset, normally vibrations are not a serious problem. the most problamatic is a U joint typically. out of balance, shocks, and wheel bearings are typically annoying, if it's a wheel bearing, I'd try to get it replaced, but I wouldn't be disturbed at driving it, drive at a slower speed and you'll be better off.

 

Um, I disagree here. If it is a wheel bearing and at the rear, it could tear up an axle. At the front end it could tear up a spindle. While a rear axle is not that hard to replace, a spindle is. Either way, it is more money that didn't need to be spent.

Start at the mismatched tires, first.

 

The factory tire size on the 91-93 pony rims was 225/55.

 

like I said, I would replace it...however, in most cases when a wheel bearing has started to vibrate, then it has some time before it will cause damage to other components including the axles and spindles. they are specifically designed this way. as a reference, both of my front wheel bearings went bad in my 99 cobra while I was cruising at 135 MPH on the way to the track...I knew because it was silky smooth as always and then it started to vibrate the wheel and brake pedal when I pressed it......when I got to the track (I slowed down to about 65-70 MPH) about another 2 hours later I found out what it was by doing a shake down. I took it back home after a weekend of watching others having fun and enjoying it all in the beautiful spangdalem area, I took my 3.5 hour drive home on these same ones, I ordered a new set while I was up there. when I returned I drove it another 2 days with a 30 minute drive in each direction, and I got the parts on that thursday (took wed. off.) and when I changed the fronts out at a local shop, I also did the rears since I was there. I inspected the spindles and there was no wear at all. on this car the hub and bearing were a complete kit on the fronts.....no spindles aren't cheap but it's pretty easy to tell.....get the front end off the ground and shake the front tires top and bottom for play, and then right and left for play....if you feel play, they need to be replaced. alternately in more severe conditions, the wheel will actually slide in and out. I'd check the front bearings first.....but more then likely you would feel the vibration at lower speeds from a wheel bearing. so if it's not that, then your wheels and tires are off ever so slightly....it doesn't take much to make a difference in smoothness on any car. balancing tires is relatively cheap....make sure the shop that does it, if you don't balances the rear tires, some shops don't because the novice car person wouldn't recognize or most times feel a rear wheel out of balance.

 

Thanks for the help guys. I'll check the bearing tonight, but I have to drive the thing to work, at least once this week, considering, I haven't drove it at all in the 2 months I've own it. As for the vibrations, when I hit the brakes, nothing shakes. When I'm cruisin at around 65 or below, nothing shakes. It only shakes bad, (steering wheel, front end), when I do anything around 68+ Anyway, I'll check into it soon.

 

Your experience is opposite of mine and a lot of others I have known throughout the years.

Telling someone to go ahead and drive on bad parts - especially critical suspension and steering parts - is very bad advice.

 

regardless it's not gonna be his bearings, if it doesn't shake below that or cause a rubbing noise, he is not giving symptoms of bearings, the bearings will produce a humming noise from about 30mph on....and when turning and weight transfer the sounds will change....