I just bought a 73 beetle and have heard a clapping noise from beneath the caron two occasions. I am learning stick and am still a bit rusty - so, it may be my shifting and not a mechanical problem. I think itoccurs when I press the clutch and brake without shifting into neutral. Someone suggested that I may not be pressing the clutch in all the way. Could this be a mechanical problem? What do you think? Any suggestion would be helpful.

 

What comes to mind, back when I was a VW tech, when we did
a brake job and machined the drums, the lathe would make tiny
marks on the surface that would act just like a bolt thread , when
you pressed the brake the shoes would contact the drum and the tiny threads would cause the brake shoe to be pushed inward toward the backing plate( plate the shoes are fastened too) then it
would pop back towards the drum and cause a clicking or clapping
noise, the only way to stop it was to adjust the brakes up as tight
as poss and still not lock the drum, or just live with it untill the drum
got polished out again. This did not cause a problem, just a noise.