TOPIC:

Hey guy, I've just replaced the tachometer seal (a pain in the arse getting it out) on my 77 a1. Putting the new seal it doesn't sit exactly flush with the housing, is that normal? And with the tacho drive in its kinda tight also, as in using my finger to turn the drive there's a bit of resistance. Do they loosen up? Photo attached.

No it should fit flush.

Did you remove all of the old one? Seal should be lower than picture.

It looks to me like you have a damaged thread on the drive unit. The other threads look to be full of grime. Either of those could cause it to be hard to re-install.

If you clean the threads with a wire brush and try to fix the damaged starter thread you can probably reuse the unit.