Not good vibrations

[Rockettvr]

Hi all
I've just replaced my recently broken drive shaft with a second hand unit. On the test run I'm experiencing a vibration around 55-60 mph so as I've not changed anything else I'm guessing somethings out of kilter with the replacement shaft. As I see it I've 2 choices
1 take off the replacement shaft and get it balanced
2 as my old shaft was fine I can disassemble the UJ and swap the broken hub ( splined) part over from the new shaft onto the old one thereby retaining 90% of my old shaft and refit that to the car
Any thoughts, ideas, wisdom, advice gratefully received
Thanks Ron

[Aeroflop]

Also check the corner for ANY loose nuts. I had also vibration at the same speeds (and up from there), therefore jacked up the corner that had got the latest work (right rear, U-joint and a wheel bearing) and found that the longitudal bolts that keep the A-frame connected to the chassis were a bit loose. Not that much that it would've been visible to the eye, but I tightend them a bit and voilà, the vibration is gone.

[adam quantrill]

Did you replace the UJ/s in the secondhand one or not bother?

They are the most likely source of vibration - if either they have a slight stickiness to them or you made a mistake fitting and trapped a needle bearing between the end cap and spider, which will make part of the joint off-centre.

If you get that side suspension off you can of course replace the whole lot (or bits of it) without removing the spline/stub axle from the bearing which saves re-torquing the hub nut.

While you have it off check for easy movement in all axes at each UJ.

[wild rover]

Most definitely the splicers. Try forcing new grease in and try if it improves you know the balance is okay and require new splicers. If the splicer is stiff as Adam explained a sharp hard crack with a hammer on the yoke normally frees it off.