This is expensive!
A complete restoration is very expensive and you should not attempt do do it yourself unless you are specially skilled or like the challenge. If you try and fail it could mean that all the expensive material you have bought is wasted. Just one mistake could ruin it all...
The only job that is fairly easy do no is to change the outer top on the newer cars (66-). But if what you find underneath is not OK...
How to check the top
Up to ´65 the top was made of a textile material (the equivalent material is today used by many makers of cabrios, Mercedes, Porsche, BMW etc). If taken care of these tops last for many years, mild washing and vaccumcleaning. Dark tops gets lighter, while light tops often gets a little dirty. After 15-25 years it starts to crack and the seams loosens up. Then the only alternative is to put on a new one. There are ready made to buy, but a craftsman normally wants to make one from scratch. There are many wooden parts in the topframe - se this (large) drawing - that tend to root away. especially the front
bow (up to ´72), the rear windowframe and the rear wooden bow (up to ´65). Check if they are soft! the frame itself often rusts and sometimes it is necessary to weld where the front bow meets the frame (especially on the ´72 model). It is fairly easy to see if the frontbow is bad. From ´73 the front bow is all steel and I have never heard of any problems with it. All wooden parts are available to all models in wood or plastic.
From 1966 the outer top is of vinyl. The vinyl shrinks , and the side wires that straightens the top are often broken, and not so easily replaced. After 10-20 years the top starts to crack and must be replaced
Be suspicious to all cars with a new outer top, if the inner roof and the padding is old, maybe the owner just changed the outer top just to cover up all that is bad underneath. Ask for pictures and/or references. Be especially careful if the owner has made the job himself!
The rear window
is a weak spot. The window frame (made of wood and steel) quickly roots and rusts away if water leaks in.
This is quite easy to see. The window should be in line with the outer top. If the window has sunk back or collapsed towards the base of the top, that is a bad sign. Often you will find a lot of sealant has been used. Originally the window is fitted in the same way as the front window and no extra sealant is used. Signs of leaks can also often be seen in the rear luggage compartment. It is likely that you will find a lot of rust under the carpet and under the rear seat.
The window frame is often completely rotten, even if it looks fairly good condition. The frame weakens and loosens its shape. This makes it impossible to fit the rear window correctly. The result is that it gets loose when folding the top up and down. A new frame is expensive, but possible to buy new to all models (not from VW they only have them for the model from ´75)
Also check that the window is mounted correctly (straight and not to high or low). If this is not correct it may affect the folding of the top and the car "looks wrong". This is impossible to correct without renewing the top (both inside and outside)
The front bow
Is made of wood up to model 1972. On the last years the bow was made of chips like a chipboard. It often soften and bulges making a gap i the middle. This results in windnoise and rain getting in. This is easy to see. Often you can see a extra moulding glued to the windscreen frame, when everything is alright no moulding is needed.
Often the front part of the frame, where it meets the bow, is badly rusted. Repair parts are avaliable.
On the 1303 this problem disappeared as the bow is made of steel.
All wooden parts are avalible and there you can also find plastic replacements of good quality.
A completely new frame?
Sorry that is no longer avaliable.
Here is a detailed drawing of the frame.
You can also read the New Top Guide