Pulsing vibration at 35mph+ in Deuce

[gem1410]

My 1970 Deuce has a vibration that starts around 36 MPH. The vibration pulses from mild to almost nothing all the way to max speed--Less vibration at 50mph+--It fells like the passengers side is where the vibration is coming from--I rotated out the right front tire for a new one and still have the same vibration--the drive shafts do not have any impact marks but I have fooled in the past--I was told the mid shaft sometimes vibrates--does anyone have any ideas on fixing this vibration--Thanks George

 

[tm america]

check the wheel bearing .and make sure everything in the front end is tight and in alinement

 

[WillWagner]

Check drive line phase and for loose flange bolts. Also check the shaft between the trans and t-case..those are always comming loose. Check to see if the drive shafts are bent and for too much slop in the slips. I had a harmonic vibration and It went away after I swapped from a sprag to an air shift t-case.

 

[gem1410]

What I have sounds like a harmonic vibration--I have an air shift--How do you check for drive line phase?--thanks

 

[gem1410]

I found what phased is--I will check it out tomorrow--Thanks---top shaft in the picture is phased and bottom is not

 

[Barrman]

Check all of your tires for pressure too. With a gauge. I had a harmonic on my Gasser that would go from nothing to big shack and back to nothing in about a mile while at speed and then repeat every 3-5 miles. One of my inner rear tires was at 5 psi or so. It still thumped like the rest, but it wasn't like the rest.

I agree with the above that it probably is a drive line issue, but thought I would bring up the obvious as well.

 

[gem1410]

I will check the tires today -- I run the tires at 50psi--what do you suggest for highway--thanks

 

[drgreg]

50 psi.

 

[FormerNewMVGuy]

I had the same vibration also, Turned out two of my inner rear tires had only 5 psi pressure. I aired them up and the vibration went away!

 

[gringeltaube]

..........How do you check for drive line phase?--thanks

Not an issue here..., Deuce drive line propeller shafts all come indexed (1 missing spline) for correct assembly only. Just check for loose bolts, worn out U-joints, slip joints, etc. as recommended above.

G.

 

[Jake0147]

My 1970 Deuce has a vibration that starts around 36 MPH. The vibration pulses from mild to almost nothing all the way to max speed--Less vibration at 50mph...

I'm not quite sure how to read that... You are saying that at any given speed, the vibration comes and goes?
If so, that would tell me it is a tire or wheel end (rim, bearing, hub) type issue, and there's probably more than one involved. tire balance, tire out of roundness, mismatched air pressure or tire diameter in the rear tires... If it settles in and stays constant at any given speed, then I'm with the folks above, it still could be a single tire issue, and also could be driveline related.

In the driveshaft picture above, the top shaft is phased correctly, and the bottom one is incorrect.
You will find that almost all driveshafts (I havn't checked on a deuce yet) will use an odd number of teeth on the spline. That means there is no such thing as 180 degrees out. If it's almost right, but not quite, it probably needs to be flipped 180 degrees.
Driveshaft segments between universal joints ALWAYS have the yokes in the same plane. They look like this ]====[ every time. If you remove every single joint, then EVERY section, from the longest section with a slip joint included, right to the little stubby piece in between the two universal joints on the right end of the driveshaft in the pictuer above, the ends are ALWAYS going the same direction.