Drive Shaft: How much is acceptable?

[Hawklover]

Now that the car is back together...........I have noticed a marked vibration in the seat........how do I know if the drive shaft needs to be re-balanced, or the universal need to be changed?

The above is at speed on the X-way.

[DEEPNHOCK]

Year/model/driveline option info needed.
Did you move the engine to a different set of mount holes?
1 piece driveshaft? 2 piece driveshaft? Different rear springs?
Sometimes a perfectly balanced driveshaft can cause a vibration if the yoke angles are not equal.
Keep after it... You'll get it!
Jeff

Now that the car is back together...........I have noticed a marked vibration in the seat........how do I know if the drive shaft needs to be re-balanced, or the universal need to be changed?

The above is at speed on the X-way.

[Dan Timberlake]

here are some tests to start.

http://www.hurst-drivelines.com/files/Driveline-Vibration-FAQ.pdf

This device would help determine if the vibration is high at wheel rpm or driveshaft rpm.

http://www.manddsmallengine.com/briggs/tools/19200.html

U-joints should move in all directions freely, but have no discernible play.

If all the joints are smooth and free with no clearance I'd use a wire pointer or dial indicator to check each section of driveshaft for runout near the ends and the middle while rotating by hand. Much more than 0.010 inch is suspect. there may be indications of missing welded on weights. the location of the missing weight is a good first guess for adding weight during the DIY balancing process described below.

Running the car up to X-way speeds while securely on stands or a lift can offer the opportunity to observe the drive shaft whipping or bouncing if the balance is bad. Brave souls experiment with one or a pair of hose clamps as balance weights on the ends with visible vibration. Move the head around until the vibration is lowest, then add a second clamp for 2x weight, then "split" the heads for a progressively lighter weight. The ro

[tbirdtbird]

This is the car you had a new ring gear/starter installed, right? No such probs before disassembly, right?
No tire/wheel changes, correct?
Was flywheel removed to change ring gear? perhaps flywheel to crank bolts not tight
Try rotating driveshaft 180* at differential.
Could be a lost driveshaft wgt as mentioned.
Vibration in relation to engine speed or highway speed?
If vibration at 50, what happens if you coast at 50?

Unrelated to this case, friend had a Sentra yrs ago with brutal highway speed-related (not engine speed) problem. Everything was tried, wheel balance, alignment, exorcism, etc etc,. He had me look at it out of sheer frustration. I rotated the spare out to each tire position until the vibration went away. Long story short, Turns out he had used that flat-tire-inflate-a-can stuff in the bad tire. It may have sealed the leak, but that goo all congealed in the bottom of the tire giving a huge tire imbalance. Could never figure out why the balancer shop didn't uncover this, unless they really did not do anything, I wasn't involved in that. For the record, once you use that stuff, your emergency may be over but your tire is now NG

[JohnM15]

Make sure your u-joints are in phase.

[Hawklover]

1964 GT hawk 4speed transengine was not moved,springs the same as before, one piece driveshaft, universal taped up before taking shaft out to remove trans..plenty of lube in ujoints vibration same at 50 or 80..

Year/model/driveline option info needed.
Did you move the engine to a different set of mount holes?
1 piece driveshaft? 2 piece driveshaft? Different rear springs?
Sometimes a perfectly balanced driveshaft can cause a vibration if the yoke angles are not equal.
Keep after it... You'll get it!
Jeff

[Hawklover]

flywheel removed to take ring gear off and new one installed no tire wheel changes

This is the car you had a new ring gear/starter installed, right? No such probs before disassembly, right?
No tire/wheel changes, correct?
Was flywheel removed to change ring gear? perhaps flywheel to crank bolts not tight
Try rotating driveshaft 180* at differential.
Could be a lost driveshaft wgt as mentioned.
Vibration in relation to engine speed or highway speed?
If vibration at 50, what happens if you coast at 50?

Unrelated to this case, friend had a Sentra yrs ago with brutal highway speed-related (not engine speed) problem. Everything was tried, wheel balance, alignment, exorcism, etc etc,. He had me look at it out of sheer frustration. I rotated the spare out to each tire position until the vibration went away. Long story short, Turns out he had used that flat-tire-inflate-a-can stuff in the bad tire. It may have sealed the leak, but that goo all congealed in the bottom of the tire giving a huge tire imbalance. Could never figure out why the balancer shop didn't uncover this, unless they really did not do anything, I wasn't involved in that. For the record, once you use that stuff, your emergency may be over but your tire is now NG

[Ron Dame]

Wasn't there a bulletin that indicated that in some instances 5 or 10 degrees out of phase helped with vibration? I'm still chasing a similar vibration in my truck.

Year/model/driveline option info needed.
Did you move the engine to a different set of mount holes?
1 piece driveshaft? 2 piece driveshaft? Different rear springs?
Sometimes a perfectly balanced driveshaft can cause a vibration if the yoke angles are not equal.
Keep after it... You'll get it!
Jeff