Car Vibrating

[mikeb89GT]

Just curious if anyone else has run into this. Seems like when Im on the Highway going 65-70 my car vibrates like crazy. Its been doing this since I got the car a few weeks ago, the tires were bad so I got new ones. While I was getting new tires I also had them do an alignment at the same time. Anyone have any ideas what could be causing this? Thanks for any input.
MIke

[PKRWUD]

Do you feel it in the steering wheel, or throughout the car? Does the vibration go away if you push in the clutch pedal? If so, it's engine related. If not, it's in the drivetrain. If the wheels have been balanced, I would suspect the driveshaft.

Take care,
-Chris

[mikeb89GT]

Ok on my way home from work tonight, I got the car to 65 which is when it starts to happen, and decelerated and it started to vibrate, seems like the whole car shakes. I then pushed the clutch in at 65 and it vibrated at that time too. I was thinking drive shaft, what do u think? It looks like a new drive shaft, maybe loose bolts?

[ex-lt1-guy]

I had the same problem, I found my front u joint was broken and missing a cap, causing me a lot of vibration above 50, once i changed it I felt like i was driving a brand new car, hope that helps

[mikeb89GT]

Yeah its real weird, seems like its only over 65 and worse on deceleration. I may check the bolts tomorrow on the drive shaft to make sure they are all tight.

[PKRWUD]

If it does it more on deceleration, I would definately suspect a bad u-joint and/or bolts. If they are good, try turning the drive shaft. It may have been reinstalled off of it's balance. If that doesn't work, I would have the driveshaft balanced.

Take care,
-Chris

[Coupe5oh]

I just posted a week ago about how i checked my d/s bolts cuz my car was vibrating on decell? sure enough, all 4 were backed out almost half way, when i tightened them, it was like i could shift better? and on the highway it got 10 times smoother, after a couple 5k launches i just did tonight at the track, i'll be sure to recheck tomorrow.... check them asap...

[PKRWUD]

BTW, if they are loose, over-torquing them is not the answer. Loctite 271 on the threads is.

Take care,
-Chris

[7000rpmisheaven]

I am getting ready to buy a couple u-joints. I was thinking about buying the ones from mustangs unlimited. Is is there a better place to buy them?

mikeb89gt- check my thread "harmonic damper removal" it seems that a bad balancer can cause a vibration also.

PKRWUD- how many ft/lbs do you put on driveshaft. Also I have a question about torque wrenches. I heard that you should get your torque wrench calibrated. How would I do this. Is there a way to test whether it is calibrated correctly? Should I even worry about it? About how much does it cost to have the driveshaft balanced.

[PKRWUD]

Originally posted by 7000rpmisheaven
PKRWUD- how many ft/lbs do you put on driveshaft. Also I have a question about torque wrenches. I heard that you should get your torque wrench calibrated. How would I do this. Is there a way to test whether it is calibrated correctly? Should I even worry about it? About how much does it cost to have the driveshaft balanced.

I don't use a torque wrench on those bolts, I do it by "feel", but I would guess between 80 and 100 ft.lbs. of torque.

Torque wrenches need to be recalibrated to ensure accuracy. Testing the accuracy of yours requires a calibrated torque tester. Usually the manufacturer offers recalibration as a free or inexpensive service. I try to have mine done once a year, but I use them every week. One thing you can do that will help maintain your torque wrenches accuracy is to make sure it's not "loaded" when you put it away. That means reversing the tension until the adjuster feels almost loose. Loose isn't good, but almost loose. Then tighten it a few pounds. For example, on my 1/2" drive Mac torque wrench, I like 25 ft.lbs. I back my wrench down to 15 ft.lbs., and then go up to 25 ft.lbs. before puting it in it's case. Every time. Also, FWIW, the best way to set your wrench at the desired setting for torquing is to surpass that amount by 10 pounds, and then go back to the desired setting.

Having your driveshaft balanced should be fairly cheap. Look up a Drive Line Service or Repair facility in the Yellow Pages, usually under Drive Shafts, and give them a call for an estimate.

Take care,
-Chris

[mikeb89GT]

Ok finally got rid of the vibration! It ended up being the drive shaft bolts like you guys said it was. Nice easy fix. I want to thank all you guys for your help. I have learned a ton reading your posts.