The single most useful thing to know before cleaning a convertible top is which kind you have, because vinyl and cloth are not the same material and do not want the same treatment.
Work out what your top is made of
Vinyl has a smooth or lightly grained plastic surface — the pinpoint grain was original on most American cars from the 1950s through the 1990s. It is a sealed surface, so dirt sits on top of it.Cloth tops are woven. Haartz Stayfast, for example, is a solution-dyed acrylic face over a butyl rubber inner layer with a cotton backing, and it was specified as original equipment for decades. Because the face is woven, it holds dirt in the weave rather than on the surface, and it depends on a factory water-repellent finish that cleaning gradually removes.That last point is the one people miss: cleaning a cloth top removes its proofing, so it needs re-proofing afterwards. A vinyl top does not.
The method
- Rinse loose grit off first. Grinding sand into either material with a brush does more damage than the dirt ever would.
- Use a dedicated convertible top cleaner appropriate to your material, or a mild soap. Work in shade, never in direct sun on a hot panel.
- Use a soft brush on cloth, working with the weave. Use a cloth or sponge on vinyl.
- Rinse thoroughly. Residue left in a woven top attracts dirt and holds moisture against the fabric.
- Let it dry fully raised, then re-proof cloth with a fabric protectant.
Things that quietly cause damage
| Avoid | Why |
|---|---|
| Automatic car washes | Brushes catch seams and the rear-window surround, and high-pressure jets drive water past seals |
| Bleach or strong household cleaners | Attack stitching thread and strip the water-repellent finish from cloth |
| Glass cleaner on a plastic rear window | Ammonia clouds and yellows plastic curtains. Plastic is not glass and wants a plastic-specific polish |
| Folding a damp top away | Creates mildew and sets creases along the fold lines, which is where tops split first |
| Cleaning in direct sun | Product dries before it can be rinsed, leaving residue bonded into the weave |
The rear window deserves its own attention
On older cars the rear window is frequently the reason the top failed in the first place. A plastic curtain clouds, then cracks at the fold line, then lets water in. Never fold a top with a plastic window in cold weather if you can avoid it, and never clean it with anything containing ammonia.
When cleaning has run out of road
If seams are opening, the fabric has gone stiff and chalky rather than supple, or water is getting in even though the top latches properly, you are past maintenance. Bring the car to the shop in Monroe and we will tell you honestly whether it needs a repair, a new window, or a new top. See our convertible top replacement page.