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Failed MGB bonnet catch - an alternative solution
In V8NOTE438 Malcolm Venables reported a dangerous experience he had suffered with his bonnet catch failing which allowed the bonnet to blow up onto his screen. He describes how it happened and recommended the bonnet catch should be checked carefully as a service item. Here Jon Moulds explains how he has developed a solution. (May 12)

A number of reports recently have described how MGBs have had bonnets fly open at speed. The cause has been due, in part, to the original type of safety catch failing to do the job it was designed for. Having experienced this first hand when a bonnet opens at speed, often several things happen: the bonnet prop is ripped from its mountings, the bonnet hinges will bend along with the rear section of the bonnet frame, the front of the bonnet will wrap itself around the roof, damaging it beyond economic repair, the roof itself may become dented from the force of the impact and the windscreen can shatter.

The whole event will take place in a split second and the first a driver will be aware of the situation is when an incredibly loud bang occurs as the bonnet hits the roof, not to mention the driver's view of the road ahead will be completely blocked whilst attempting to get the vehicle to the side of the road: a potentially life threatening situation.

What can we do to ensure this dangerous situation doesn't occur? The first essential check is to ensure both the bonnet catch and safety catch are properly adjusted. *Note* Whilst working in this area, the bonnet release catch and cable could probably do with greasing as they are often forgotten about until at the crucial moment the cable goes "ping".

As an extra cautionary measure, some owners elect to fit a bonnet strap. This is a fine solution so long as you don't mind non-original features, but what can an owner who is both safety conscious, yet would prefer their car continued to appear standard from the outside do? Well, for those with originality concerns or a rubber bumper model that cannot easily be fitted with a bonnet strap, there is now an alternative solution in the form of a second safety catch.

The solution I came up with was to utilise a "break away cable" kit as you can find fitted to caravans or boat trailers and a small U clamp. The kit adapted to the MGB bonnet comprises of a simple sprung clip, like a carabiner, at one end which should be attached to the existing U bracket on the slam panel of the car. The other end of the suitably shortened cable is secured to the original safety catch with a clamp.




The installation is quite straight forward as follows:
> Remove the 3 bolts holding the safety catch to the bonnet.
> Drill two small holes through the handle of the release mechanism.
> Shorten the cable to around 8 inches in length.
> Pass the cable through both of your pre-drilled holes and loosely fit the clamp.
> Reattach the safety catch to the car.
> Adjust the length of the cable to suit the car. You should aim to keep the cable as short as possible whilst giving enough free play so you have space to reach in and operate the sprung arm of the carabiner.
> Tighten the clamp up and trim off the excess cord.

The plus points of this modification are it allows the car to maintain a standard outward appearance but gives a third layer of security in case the bonnet catch and original safety catch fail. The only down side is that you will need to release the sprung clip of the carabiner every time you open the bonnet, but arguably this is no more effort than having a leather type bonnet strap fitted?

Suitable breakaway cable kits can be sourced from either your local automotive supplier, your local caravan and camping supplier or even your local chandlery. Suitable U clamps can often be sourced from the same suppliers or even from within the lighting section of a DIY home improvement store.


See our illustrated A4L PDF note online for better copies of these photos. More
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