NA bouncing bonnet

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Forgiven
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NA bouncing bonnet

Postby Forgiven » Fri Jun 19, 2020 5:49 pm

On the highway my NA bonnet bounces. It's secure, but disconcerting. Is the fix something that I, a non-mechanical minded (and tool limited) owner can fix?

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KevGoat
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Re: NA bouncing bonnet

Postby KevGoat » Fri Jun 19, 2020 7:35 pm

I recall my NA's bonnet use to lift disconcertingly at high speeds, they're quite thin & light. I just checked the front latch was positioned and locked in correctly and checked the hinges.

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Re: NA bouncing bonnet

Postby manga_blue » Fri Jun 19, 2020 9:13 pm

Has someone fitted gas lift struts to it? They tend to make the bonnet bounce.
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Re: NA bouncing bonnet

Postby Forgiven » Sat Jun 20, 2020 11:24 am

manga_blue wrote:Has someone fitted gas lift struts to it? They tend to make the bonnet bounce.


Nope, just the standard single arm that one lifts up and sticks in the underside of the bonnet.
To my uneducated eye there's too much play where the bonnet attaches at the front.
I'll see what a couple of guys say when I go for a Club run next Sunday.

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Re: NA bouncing bonnet

Postby 93_Clubman » Sat Jun 20, 2020 11:32 am

Are the black rubber bonnet bump-stops that the bonnet rests on still present?

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Re: NA bouncing bonnet

Postby Forgiven » Sun Jun 21, 2020 9:45 am

I had a careful look at what was going on. The connecting ring in the middle of underside of the bonnet had play in it when engaged. Couldn't see how to adjust the catch into which it went, so bound the ring with some self-fusing silicone tape. That is, made it fatter in its middle. Not the professional solution I'm sure, and presumably, it will need to be replaced periodically, but it doesn't rattle anymore. (In the garage at least.)

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Re: NA bouncing bonnet

Postby 93_Clubman » Sun Jun 21, 2020 11:14 am

Are the black rubber bonnet bump-stops that the bonnet rests on still present? They're at the front corners of the bonnet & if missing will allow freeplay.

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Re: NA bouncing bonnet

Postby Forgiven » Sun Jun 21, 2020 11:31 am

93_Clubman wrote:Are the black rubber bonnet bump-stops that the bonnet rests on still present? They're at the front corners of the bonnet & if missing will allow freeplay.

Yep, still there.
The shut lines around the bonnet and headlights are not right I don't think, plus I think the front clip is not the original, so a front end bump in the past maybe is the cause of the catch being out of line.

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Re: NA bouncing bonnet

Postby 93_Clubman » Sun Jun 21, 2020 11:36 am

Fair enough, you can twist the rubber bump stops to raise or lower their height, but if flush then will look out of place.

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Re: NA bouncing bonnet

Postby Forgiven » Mon Jun 22, 2020 5:14 pm

93_Clubman wrote:Fair enough, you can twist the rubber bump stops to raise or lower their height, but if flush then will look out of place.

Oh, I didn't realise that. Thanks. (I thought they would be designed to be hard down.)

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Re: NA bouncing bonnet

Postby StuwieP » Mon Jun 22, 2020 6:50 pm

Forgiven wrote:I had a careful look at what was going on. The connecting ring in the middle of underside of the bonnet had play in it when engaged. Couldn't see how to adjust the catch into which it went, so bound the ring with some self-fusing silicone tape. That is, made it fatter in its middle. Not the professional solution I'm sure, and presumably, it will need to be replaced periodically, but it doesn't rattle anymore. (In the garage at least.)


For mine, the catch is literally just worn out from use - so it's thinner where the clip engages than the rest of the d-shape. Sounds likely your issue too. I tried to adjust the catch lower to remove the play but without luck. if it works, it's a solution right?
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