[Vwdiesel] ALH vacuum pump

[S P SHERMAN]

My '00 Golf has a vacuum leak somewhere. I've done a quick inspection of the vac lines with no obvious culprits. One thing which I found that seems suspicious is that the  nipple on the vac pump itself is loose (the one the main vac lines goes on); it rotates and has some wobble where it enters the case of the pump.

My question is, is this normal? Shouldn't the nipple be tight on the pump body? And if it is not right, does this nipple screw into the pump body or can it be tightened again?

 

Thanks