Ok so just bought a 62 beetle, with a 1600 twin port. Lost drive the other day - I'll explain: goes into gear fine clutch out fine but no drive. I pulled of the passenger rear hubcap and found metal shaving on the lip of the rim, the split pin on castle but was snapped and the axle and castle was just spinning lots of grinding noises. The bug is seriously low with massive camber, the last owner told me it has euro wheels and runs 185's. It's my first bug, I've had it for 3 weeks.

So the questions:

My bug must be IRS to get that much camber?

I'm guessing there is the gearbox output, CV, driveshaft and then a spline on the end of the driveshaft that slots into the rear drum? Then I'm guessing it's the rear drum spline that has failed/been chewed out? So basically I need new drums?

Everything from the chassis down is new, new brakes, reco gearbox, reco engine, new suspension (narrow beam and adjustable spring plate), new everything with patina body sitting on top. So if this is the case why has the rear drums failed?

Will this be an on going issue with my wide wheels, lowered suspension and camber?

Do I have the whole idea of how my driveline works right? Do both wheel get power from the gearbox or just the passenger side as that seem to be the one that is spinning?

Cheers guys sorry for the newbie questions.

Your bug would be swing axle. You have stripped out the spline in the drum. You need a new drum. Only one side is spinning because of the diff. It will spin the unloaded side while the other side is stationary. It may or may not happen again.

They chew out when they get loose and.or of poor quality.

Get the axle nuts tightened correctly on the new ones.

good looks and reliability dont always go together

As said above - raise it a bit

Every inch raised will add longevity to your drive line

How could the rear axle or its splines be broken by a 1600? Would it mean that the rear axle nut had been loose for a while and the whole lot was wobbling about under load?
If it's due to a loose nut, would it be just OK to renew the parts?

The fact that the drums are "relatively new" rings alarm bells with me. Try to get hold of a pair of good 2nd hand original drums, as they are much better quality than the 'new' after market drums.

Hopefully, the axle splines are OK, as they would be harder than the crap drums that have obviously been fitted. Make sure the axle nuts are tightened to the correct torque, and regularly.

And raise the rear end...that will remove a lot of the load on the splines.

Do both wheels drive (LSD) or is it just the passenger side?

Both wheels should get the same amount of drive in normal operation... The factory/standard diff's are all conventional types (apart from some rare 1960's factory LSD ones) using spiral-bevel final drive.
ALL factory rear ends are independent (IRS), so it's unclear to just use that label.
Earlier ones are SWING-AXLE: larger-looking Closed Drive-shaft.
Later ones are FOUR-JOINT: thinner-looking Open Drive-shaft, with 4 C.V.-universal joints (often called "IRS").
It's easy to look underneath (subject to lowering!) to see which type of rear axle it is.
If lowering causes "massive camber", you probably have the earlier swing-axle type. It's meant to be bad to have a swing-axle with large camber as it can starve the rear wheel bearings of lubricant (oil from the diff.).