There is a vast difference between the simple soft-top of a Frogeye Sprite and the complex, multi-layered convertible top of a Jaguar XK150 DHC: while one can be replaced in its entirety for little over $150, the other can easily cost thousands to recreate. And the quality of the top is not necessarily related directly to the value of the car – Volkswagen Beetle convertibles have top-quality lined and padded tops from Karmann that can be just as costly to resurrect as those on Aston Martins and Ferraris.
If you’re thinking of buying an open-top car, the first thing you should do on arrival, if the top is down, is to ask the owner to put it up. This will show you how well he’s treated it, how difficult it is to put up and if there are any major faults with the mechanism. It's also essential for the test drive as, with the top up, you hear the nasty noises from the engine, transmission and suspension that with the roof down you’d never imagine were there – and you can see how secure and wind-proof the top is when driving.
Restoring an original
Don’t be put off by a top that has faded; you can re-colour it. The process, using products such as Renovo, will also help to waterproof the top if it has become a little porous. Older products such as Maxol are quite thick and, though effective on very worn tops, can bulk up the material and make it stiff.
Recolouring a faded top is a great way to preserve the originality of a well-patinated car, and the importance of preserving an original soft-top cannot be overstated: it can be extremely difficult, not to mention expensive, to get as good a fit and finish again. Renovo’s range includes colour restorer in black, dark blue, brown and green, plus cleaners and waterproofers, for fabric tops; it now also includes cleaners and waterproofers for vinyl tops (which do not fade, so don’t need to be re-coloured).
Plastic rear screens go cloudy with age, due to scratching and UV exposure. They can be improved dramatically with specialist plastic polish but, if split, must be replaced. There’s no need to replace the whole top: a trimmer can renew just the window, or you can buy sheets of Vybak window material and the necessary tools to do it yourself from RatSport.
Prestige Car Tops has come up with an MGB top complete with glass rear screen with heated rear window that you can fit yourself, folds down as normal and costs as little as $400 complete; a window like this could be incorporated into a range of other 1960s soft-tops if desired.
Vital to the fit of the top and its durability is the condition of the top frame. If your top is awkward or stiff to put up, or the top material is chafing on the frame, something is probably wrong. Talk to others in the owners’ club and look at the frames on their cars.
Frames can become bent and can even get broken through rough or incorrect handling, and they don’t always get repaired accurately. Wear in the pivots can dramatically affect the shape and tension of the top frame, leading to the frame sagging above the windows, the top not fitting properly and the door windows not lining up with the top; that in turn can cause leaks, pinched and damaged top material, or a flapping or lifting top.
Repairing a worn top frame may entail its complete removal from the top and the car, so that worn pivots can be built up with weld, redrilled and new pivots inserted, but it is definitely worth the hassle.
Top frames from the 1950s and earlier often contain wood, because it is the ideal material to hold nails and tacks locating the layers of headlining, packing and top materials. Unfortunately it rots, warps or simply weakens from excessive use and needs specialist replacement.
On a quality top, there’s a great deal more between the frame and the cover than you may think. There’s the headlining, of course, then padding, which would originally have been horsehair – and this is still the best material for the job. It is spread out very carefully and held in place by layers of calico cloth. The spread of the horsehair and the tension of the calico and headlining are critical.
When you come to the outer covering, there is a bewildering range of materials available. You thought it was just vinyl, cloth or mohair? As Mick Turley of MCT Jaguar Restorations explains, there’s more to it than that: ‘German mohair is the best: it just doesn’t fade at all and still looks like new after 15 years on the car, if it’s kept clean. Then you can get contract mohair, which is two-thirds the price, or English mohair, or Twillfast or Stayfast which are half the price. Then there’s Double Duck, or canvas, which goes grey with age; and Duck, which is, as it sounds, half of Double Duck and is the cheapest cloth option. Then there are various vinyls, of which Everflex – used by Rolls-Royce – is the best.’
Mick is the first to admit that you might not need to pay for the most expensive option, especially if you’re selling the car, but if you want a perfect top that will continue to look that good for decades to come, paying the top craftsman makes sense and so does choosing the best material. The only downside (apart from cost) is that a top made with the top mohair may be a little bulkier than a vinyl one, calling for all the trimmer’s skill to ensure that it will fold smoothly without chafing on the frame or the car. Mick makes another good point: ‘Be extra careful when you’re restoring the bodywork of a drophead. Talk to the trimmer and make sure that you get the panels around the top-well spot on – otherwise it can be impossible to make the top fit and fold without chafing, which can ruin a very expensive top in no time.’
All tops were once canvas or duck, with mohair becoming the choice of quality and vinyl the choice of cheapness. Today, owners often retro-fit higher-quality tops.
If you’re buying a top to fit yourself, the first thing you should do on taking it out of the packet is to lay it over the existing top and compare the size and shape: cheap pre-made tops often skimp on material and if the top is not as wide as it should be over the side windows you will get leaks and wind noise problems that are just not acceptable.