Ian Barrett gives us a run through on his Modification for his bonnet stay. They are well known for being pretty flimsy and useless along with you having to be pretty cautious not to burn your hands on them too when using them after the engine has been running.

There are a few other Bonnet Stay Mods out there by Steve Heath and Mod-Wise but I think you'll agree this a pretty good one too. Cheers Ian.

Why modify?

I modified the bonnet stay on my pre-cat 4.3 because the original upright ‘strut’ was fouling the bonnet heat-shield, rubbing a hole in the heat-shield and there was potential for, with enough time, the bonnet to be damaged too.

Oh, and on the whole the thing was pretty ugly. 

I also wanted to make it a bit more useable, and this became a major part of the design. Inserting a universal joint into the strut gave the flexibility to stow the strut in its usual position whilst allowing it to be bolted to the crossbar for stability.

It also allows the strut to attach to somewhere other than the wing so you can work on the passenger side of the car without it being in the way. Putting a cable tie on the front chassis member allows the strut to stand on the chassis, tucked under the cable tie so the wind can’t lift the bonnet.

The end results of my work are Pic1 where it is in the stowed position and Pic2 which shows the Universal joint used.

Stowed Away

Universal Joint

OK that’s enough chat, let start modifying.

The original stay has a double kink at the bonnet end and a single 90 degree bend at the other. The wing end is left untouched.

The bonnet end has to be attached to the crossbar in a manner which will fix it firm. Getting it welded was an option, but the angles would all have to be worked out beforehand, making the job difficult, so to allow for on-the-car tweaking I attached the strut to the crossbar by bolting them together.

I cut the bonnet end of the strut so there was only a single 90deg bend at this end. Tapping out the end so a M6 bolt can be inserted into it.

The strut attaches to the crossbar utilising the original hole in the flat plate on the crossbar. To bolt them together you need a washer at the front and back which is bigger than the hole in the crossbar plate. At the front this is a simple washer, but at the back is an arm which takes the weight of the bonnet when the crossbar bends under the weight. A hole is drilled in this which is just big enough for the bolt to pass through and a slightly bigger countersink is drilled at the back which is just big enough so the strut sits into the countersunk hole.

If you haven’t done so, now is the time to insert the universal joint into the strut. I bought mine from a remote control model shop. Modellers use them as drive shaft UJs. Or if you want to push the boat out you can get one from RS components. Whichever you choose, you need one which fits a 6mm drive shaft.

You can then get a good fit to the bonnet strut by gently filing the end 5mm or so of the strut so as to make it a tight fit into the UJ. As I said earlier, this fits into the strut just a couple of inches from the top bend. The extra length created by inserting the UJ isn’t necessarily a problem but measure it all up because you might need to cut a bit out to stop it fouling the bonnet edge when folded into the stored position.

Fit the crossbar, strut and bonnet support arm together and bolt loosely. Twist the UJ so it allows the strut to fold into its usual stored position and align the angle so the UJ is straight through when the strut is attached to the wing. Tighten the bolt to pinch it all together and the job is done.