[Mgs] Driveshaft orientation

[PaulHunt73]

Yes the sliding joint only ever goes towards the gearbox, and the UJs do have to be aligned correctly.  My Haynes has an exploded drawing showing them incorrectly aligned and assembled drawing showing them correct.  My WSM is correct.  It's much easier to show in a picture of course, but I'll try describing it in less than 1000 words.

The flange halves of the UJs must have their axes in the same direction as each other i.e. if the gearbox flange half is vertical then the axle flange half must be vertical as well.  Get it wrong and you get excessive wear in the UJs .

But that's not the whole story.

As said the sliding joint comes apart which means it can be reassembled in as many ways as there are splines.  Two of these ways will give the correct flange orientation, but only one of them is how the shaft would have been balanced originally.  Get them 180 degrees out and you could get significant imbalance and vibration.  There should be alignment marks on the two halves of the sliding joint but they are often missing and even when there are very faint.  More info with pictures here http://www.mgb-stuff.org.uk/ps.htm

Both Haynes and the WSM make great play about when removing the propshaft you should mark the flanges it goes back on the car as it came off.  That's a nice to have, but it's not essential, as the shaft is balanced as a unit and should run correctly whichever way the pairs of flanges are bolted up to each other.  After all, if you were buying a new propshaft the flanges wouldn't have been marked.

PaulH.
  ----- Original Message ----- 


     The sliding joint (sleeve & spline) end is forward, toward the gearbox.
      As the driveshaft may have been separated at the sliding joint (they will pull apart when off the car), check that the yokes of the universal joints are aligned.
  Bob



  On Aug 25, 2021, at 3:29 PM, <jimray at hartcom.net> <jimray at hartcom.net> wrote:


    Can anyone give me the correct orientation (front to back) of the driveshaft on an 80 MGB. Does the end with the sleeve and spline connect to the differential or the transmission. I’ve seen examples of both configurations.
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