Replacing the Bonnet Struts
Paradise Garage




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© 2000 Brian F. Schreurs
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Cheap tires are like cheap wine and cheap women: You'll regret them later.
According to the service records we inherited with the Paradise Garage 1985 Jaguar XJ-S, the original equipment bonnet struts manage to last for less than a year before they go all saggy and droopy. This is laughably unacceptable. And we hated the makeshift prop rod that came with the car! How inappropriate for a Jaguar. To top it off, the struts that come in green Jaguar boxes run near $100 each.

Fortunately, there is an alternative. Thanks to Kirby Palm's Experience In A Book, which is available for free download off his website, we knew we could safely replace the bonnet struts with aftermarket alternatives. Not only that, but we could make the bonnet open better: struts could be had which would open the bonnet further than stock! Also, according to John Napoli's suggestion in The Book, it was easy to make the bonnet open itself. Well we know a good thing when we see it. So we hustled on down to the local parts emporium, grabbed a pair of Pro-Lift #92307 struts (for a 1984 Honda Accord hatchback), and completed the Palm/Napoli Bonnet Strut Mod.

This is an old, original, weak bonnet strut best used for propping doors and garbage can lids. It is bolted to a stud at both ends.
Open the bonnet. Take a moment to marvel at the V12 because, if you're a car guy, then you have to take a moment to marvel at any V12, no matter how often you've seen it. If you don't understand this, then you're on the wrong website. "Ahhh... vee-twelve" is an appropriate homage. You may place extra emphasis on the twelve if you wish.

You will need an assistant at some point in this operation. If you're not using a prop rod, that point is now. If you have a prop rod, then you'll still need one in a few minutes.

Disconnect the old worthless struts on the body-side. If you don't have a prop rod, be sure someone is holding the bonnet for you. If you have a prop rod, then no harm will come to you by undoing the struts. All of the bolts holding the struts in place are 1/2".

Hook a tape measure round the end of the strut where it connects to the bonnet, and extend it out to about 30 inches. Lay it along the path of the strut. Now have your assistant (if you haven't had one up till now, go get one) slowly tilt the bonnet forward. Instruct that he continue to tilt forward until the 22-1/4" mark lines up with the body-side mount hole. Meanwhile you will be watching the front grille very closely. If you see or hear anything which appears as though it could be the $200 grille getting ready to snap, tell your assistant to stop.

Where the grille hits the bumper is the only tight clearance. You don't want to break that grille.
In our case, we had no problems. Most cars should have enough clearance. You have, however, been warned to check.

This is the only clearance that needs to be checked. Set the bonnet back on the prop rod or make your assistant sweat it out for the next 10 minutes, as you prefer.

Remove the bonnet-side of the old worthless struts.

Go get the new struts and reinstall on the bonnet-side.

Ohhhh, haven't been paying attention? Very well, we were paying attention and will now save you some grief. The charge-side of the struts go toward the body. The proper arrangement for the hardware is as follows: bolt head, washer, spacer (with strut riding over it), nut (tightened up to the spacer), washer.

The safety catch should fold and lock back, thus.
Note that the original struts were fairly snug in the space allotted by the spacer, but the replacement ones are not. After repeated openings and closings we have determined that there is no evident harm in this.

We're wimps and were unable to compress the struts to align them with their body-side mounting points. If you're manly enough to do this, bully for you. Instead, we had our assistant hold the bonnet far enough forward that the struts naturally fell into place. Easy.

From now on the bonnet should hold itself up. Now for the self-opening portion of this exercise!

Basically, these struts are pretty darn powerful. But there's a safety catch which gets in the way of the struts opening the bonnet. It is located on the bonnet, lefthand side. Napoli recommends knocking the retaining pin out and removing the assembly; we found that on ours it has a retracted "locked" position and was relieved of duty simply by pushing back on it till it clicked.

That's it, congratulations! You now have a bonnet that opens itself, opens further, and most important, stays open.

Just for grins we took measurements of the bonnet clearance. Mesuring from the corner of the bonnet to the corner of the bonnet's recess in the bodywork, with the prop rod we found a mere 33 inches of clearance. With the Pro-Lift struts in place we got a much improved 46-1/2 inches! It even looks better this way.

The first time you release the latch and watch the bonnet arc open on its own, you will stand in awe. It is magnificent. After a moment you will wonder how you are to close it again. The operation is simple with practice. Keep the driver's door open, push the bonnet closed with the left hand, and reach in for the latch with the right. You can do this without even looking awkward if you practice at home a bit. Plus, while you practice, you get to watch that bonnet go up. It's so cool.

Thanks to Kirby Palm and John Napoli for coming up with these ideas!