When is a Tear Not a Repair?

It's not very cold out there yet, but it is believed a cold winter is ahead of us, which is bad news for cabriolet owners with plastic rear windows.

The freezing cold weather tends to make the plastic windows very brittle and more prone to damage - this is reflected in the number of customers we get in the December & January months.

It is one of the most annoying things when you realise that your perfect looking hood has a hole in the plastic rear window! The hood looks great, except for the hole/rip/tear in the window. It seems a shame to have to replace the whole hood if it's just the window that needs replacing. Luckily it is often possible to only replace the rear window, rather than the whole hood!

Every car design has a different type of hood, sometimes there's even a choice of hoods with a whole list of different types of rear window. The Mazda MX5 for example comes in a choice of material - vinyl or cloth - and a choice of window - plastic, heated glass, zipped plastic, non-zipped plastic, zipped heated glass, non-zipped heated glass and some other variations.

9 out of 10 times a plastic rear window can be replaced, some easier than others. For example the BMW E30, BMW E36 and the BMW Z3 mostly come with a zip going right round the window. This means that the only labour costs involved is unzipping the old and zipping in the new rear window - a 45-minute job. You have to make sure tough that it is an OEM window so that you can be sure that it fits properly.

The Mercedes 129 however is not as simple as that. The window is stitched into the actual hood, wherefore the whole hoods needs to be removed in order for the stitching to be unpicked and the new window re-stitched. There is a lot of work involved here, so the price for replacing this window can be quite high, but this is still a cheaper option than getting a whole new hood.

The Mazda MX5 also has a zip, but only at the top of the hood and does not form part pf the window assembly. The window is stitched into the hood. This means that like the Mercedes hood the hood needs to be completely removed, the stitching unpicked, and the window replaced.

The Peugeot 306 has a very interesting way of attaching the window to the hood - it is melted into place using electrodes. There are wires running round the rim of the window through which a current is passed which in turn heats it up and bonds it to the hood. We suspect only Peugeot garages are able to bond a window in this way.

It is still possible for us to replace the window, but not using the electrode method. What we would do is remove the old window, and replace it by stitching a new one in place. The only difference here is that the stitching is visible.

Some hoods have a bonded rear window, which means that window is bonded to the hood using heat. A special press-welder does this and bonds and presses the heated molten plastic into the hooding material. ETC owns such a tool, which enables us to bond windows into the hood. The whole hood needs to be removed to do this so that the old window can be taken out, and a new window can be bonded into place.

The other day we had an old MGB come in with a small hole in the rear plastic window. The owner wanted us to replace the damaged section only but sadly this particular hood has a rear-window that covers both the rear window and the side windows. We advised our potential customer to buy a new hood, as the labour cost to unstitch the whole section would cost more than to buy a brand new vinyl MG hood.