Front crank oil seal replacement

[Simmo78]

Good afternoon all,
I’m just in the process of replacing the water pump in my S4 FHC and after much deliberation still haven’t decided when is the best time to install the front crank oil seal.
I have manufactured an alignment tool to ensure the seal runs concentric to the shaft and to ensure it’s all aligned with the back plate.
My dilemma is, do I fit the back plate and timing chest with the alignment tool in place and torque everything up then remove the mandrel and tap in the seal, or do I fit the back plate and timing chest then remove the timing chest to fit the seal before refitting (but risk misaligning things)
Any thoughts gratefully received, thanks in advance.

[Hawksfield]

Hi
Quick answer, complete and torque the chain case then fit the seal. Just like you will probably do it in few years time.
Good luck