vibrating mk1 again

[noise]

my -76 mk1 is vibrating again, the vibrations dont stop even if i turn of the engine, so i think it is the propshaft

the uj is new and i had it balanced 2years ago.

i feel a little gap in the sliding joint

[redeemer]

Middle bearing and rubber ok?
are th end joints of the prop shaft in line with each other? That is if the output shaft of the gearbox (where the uj mounts) is horizontal, the one on the diff has to be in line with that that is horizontal.

also to determain which part of the half is knakered, I jacked the van from back, and then my bro stated and engaged in gear, and I did see the wrapping up and down of the bad section, at certain harmonic speeds.

[baconsdozen]

Jack up the back of the vehicle and support it well on axle stands.Take off the wheels and preferably the drums,remember not to touch the brake pedal.Start it and run it in gear note the speedo reading where the vibration is at its worst.
Put it in neutral,make up a stand using something like a bottle jack and adjust it so it just touches the rear section of the prop in the middle.Slowly turn the prop,you might find it is no longer true,if so mark the low spot (bit closest to the ground) .Position a jubilee clip on the shaft with the clamp bit exactly opposite the low spot you marked.Try the vehicle again.If the vibation is worse,rorate the clip 180 degress,if its better add another clip,if that makes it better still junk the prop but if adding another clip makes the vibration worse again the loosen both clips and rotate them apart in opposite directions.
Repeat the operation on the front part of the prop if it's of the split type.
It is acceptable to use a clip in this way,the centrifugal force need to cause it to open is far,far in excess of what ever will be encountered on a rotating prop shaft.