P38A What have I done now

Hi guys right I've changed front and rear ujs and I now have developed a low drone from the rear end over 70 mph. Below 70 it's fine. I've been back under car and not got any play in the new ujs and all the bolts are tight. Oh it's a my 2002 4.0 cheers guys for any light you can shed on it

Did you mark the flanges and the shaft and fitted in the correct rotation?

Maybe knocked a balance weight off??

Marked the flanges but not the shaft don't understand what you mean about correct rotation though

the fact you marked the flanges means you have fitted unit in the correct rotation....i.e. With the marks aligned.

Marking the shaft relative to the flange is done so when you fit a new yoke the flange and shaft are aligned in their original rotation to each other too.

Remove bolts and turn round one hole and put back on and try, if not OK turn again

rogerboy said:

Remove bolts and turn round one hole and put back on and try, if not OK turn again

Click to expand...

Not possible to do that.

You could rotate one end 180 degrees, but I'm not sure if that would make any difference?

Could it be a tight UJ that just needs to bed in a bit?

Saint.V8 said:

the fact you marked the flanges means you have fitted unit in the correct rotation....i.e. With the marks aligned

Click to expand...

What happens if you fit a brand new propshaft and you have no marks to use? Serious question. Does it need balancing in situ or something?

Saint.V8 said:

the fact you marked the flanges means you have fitted unit in the correct rotation....i.e. With the marks aligned.

Marking the shaft relative to the flange is done so when you fit a new yoke the flange and shaft are aligned in their original rotation to each other too.

Click to expand...

marking the shaft at the sliding joint,to ensure phasing is correct flanges will only fit in correct alignment

MrGorsky said:

What happens if you fit a brand new propshaft and you have no marks to use? Serious question. Does it need balancing in situ or something?

Click to expand...

you just bolt it on after checking its phased correctly (new ones have been known not to be)no balancing needed or marking of flanges

Cheers guys after reading what you have all said I think I've made a boo boo with it so may as well take them off and see about getting them re balanced