When considering purchasing a Golf MK1 consider this unassailable fact right at the outset.... the vehicle will be at least 25 years old.
Stop and think just how many of the vehicles' then contemporaries may still be seen in regular use on the road; I don't know about you but I have not seen a Ford Rs1600i or XR3/XR3i, Alfa Romeo Alfasud Ti or Talbot Lotus Sunbeam in use for a great many years? Except perhaps at Castle Combe circuit where a few ol' timers can be seen breaking down in the pits along with their modern day successors wannabe supercars, Supapoo UnImprezas*, much to the amusement of the VW owners!
* Yes, I have driven one - it was a load of pony (and trap) - work it out Supapoo owners, I would rather have my 2000cc AUDI engined 16v Golf Mk1 GTi anyday!.
Primarily, the culprit for the demise of these cars, all great performers of their day, is tinworm. The other factor is simple neglect of owners who fail to undertake routine maintenance.
Rust is prevalent on Golf MK1 models, particularly in the windscreen scuttle, A pillar and rear valence. Please note whilst the former and second area may not be too serious, gout in the rear valence can be terminal; nobody produces pattern replacement parts, the VW panels have long-since been deleted from ETKA and dependent upon severity total re-fabrication of the deceased panel may be necessary. This is extremely unhealthy for one's wallet and will make one's bank manager somewhat peturbed. If there is evidence of a previous rear end shunt then proceed with extreme caution; a poor repair in the past may leave the vulnerable tailgate area with nothing more than an abundance of filler and brown dust (formerly metal, now rusted beyond serviceable use.)
Other problem areas are the spare wheel well and the front and rear inner arches. Filth gathered from the road (or rally course!) collects and rots from the inside outwards. It is merciless and may result in lethal welding bills (on the basis that there might be sufficient good metal present on the vehicle to weld patches to...)
Non-sunroof models are available, even in GTi guise but usually only in older models (X-reg). There is some virtue in seeking these out (particularly if your Golf is destined for track use - much strength and anti-body flexing capability is invested in a tin top) because the rain gullies and soak away channels in the factory installed units are prone to rusting. I have seen examples of A-reg models with annihilated sunrooves, that are all but impossible to repair, irrespective of how much money one might be willing to part with. Aftermarket sunrooves are usually likely to leak, have poor seals or simply detract from the vehicle itself... It is a matter of personal taste.
Another example of, 'rust in peace', or should that be pieces, is the hatchback aperture (where the hatchback closes onto a rebate) where poorly fitted and probably perished rubber seals allow water to rot out the aperture and usually the door skin of the hatchback - we've all seen hatches grotty along the bottom edge 'eh? Suspension turrets are also know favoured places for the Golf MK1 to suffer - usually the gaut permeates from below, upwards and outwards - a nasty suprise and not cheap to put right, underpinning the value of Waxoyl and maybe a good coating with a quality Scholtz spray treatment. I would recommend 3Ms version for viscosity and longevity.
If you are paying for a vehicle restoration, make certain the workshop is equipped with the tools, skill and knowledge to carry out the task. I am fortunate in that my friend has 40 years industry experience but for most they must rely on recommendation. If possible do try and get a photographic record of all aspects of the restoration; such evidence displays the problems encountered, how they were tackled and adds to the vehicle's perceived value if re-sale is likely to occur further down the line. In conjunction with photographs, do communicate with the bodyshop and conduct regular inspections of the work in progress. I would be very wary of any workshop unwilling to accommodate unannounced, ad-hoc visits - have they got something to hide?
Interiors may be a little sorry for themselves but whilst door cards and furniture may need to be specifically sourced, VW Golf MK2, Rovers and some Fords are quite happy to donate suitable comfy seating.
If engines are excessively smoky then assume it will require either a rebuild or replacement (sometimes this is not all bad, particularly if you were considering an engine upgrade anyhow...) Golf MK2 digifant PB engine coded GTi 8v engines or Golf MK3 / Corrado 1800 or 2000cc 8v engines are good donors to use. 16v and G60 engines are rarer, therefore more expensive but also more expensive and difficult to install as engine wiring looms require modification. Just how many engines for sale are listed with the complete, intact engine loom? Also electronic components are necessary, i.e. ECU and ignition module and these may be pricey. 1.8 Turbo 20v conversions are a nonsense, same as VR6; simply too much torque for the lightweight body shell - don't waste your time and effort.
Golf Mk1 footbrake travel and sensation are legendary.... when used for the first time one finds it horrifying to think that such braking effort expended by the driver is rewarded by so little by the master cylinder and servo on the 239mm discs. Yes, the car was designed a LHD for the German market and then when introduced to the UK it required a truss-rod to be run the full length of the engine bulkhead to apply the braking pressure.
Consequently, UK specification Golf Mk1's essentially had VERY POOR brakes, yet suicidally VERY FUN brakes. They may be easily improved by using later Golf Mk2 16v 22.2mm master cylinders and servo but also the 256mm discs and hubs from such models. This latter conversion is existing brake system dependent as there are at least three different permutations of factory supplied front brakes.
Contrary to popular belief, rear disc conversions are something of a nonsense with this model. The rear axle mounted brake compensator, which diagonally splits and apportions braking effort to front and rear is really only a token innovation. It nearly works but not quite. One would be best sorting 280mm discs, calipers etc. from a Golf G60 or Corrado and fitting them to the front retaining the original drums on the rear. TSR-Performance manufacture extension fitting brackets ideal for this conversion. Call Tom, formerly TSR-Performance's Chief Technician and Workshop Manager at his new venture, RetroResus on 01278 - 686998.
Once you have accepted the fact that you are extremely unlikely to pick up a mint condition Golf Mk1 on eBay, albeit rather a tidy, usable running restoration project at best, then you are in the realm of common sense. Of course, sometimes you might come up trumps but more often than not you may be the top of a list of between 10 to 15 previous owners (some of whom may have treated the old gal with something less than respect) consequently your pride and joy may have a number of areas which, 'need a little love'.
However, it can be very difficult, bordering on impossible, to economically bring back to life a vehicle which has suffered chronic neglect. Also, once you have shelled out, where do you insist on calling a halt? Some vehicles may be borderline, whilst others are a moneypit. Avoid the latter by taking strenuous lengths to carefully and thoroughly inspect the vehicle before parting with your hard earned pounds, shillings and pence.
If buying via eBay, DO go and view / drive before bidding.
There are a great many forums and informative books you may use to personalise your Golf MK1 and you may even like to try your hand at some of the enhancements I have mentioned. Just one small thing to bear in mind... Never over-estimate your capabilities (particularly with brakes! Arrrgggghhh!!!) and always be prepared to ask advice.
I hope this guide may be of some use to you in the process of selecting what was and still remains, the original hot hatch and ONLY model worthy of the legend GTi (Peugeot, I spit on you for badging that 206 litter with this monicker!)