I was on the track at Donnington this evening when my bonnet decided to part company with the car at 90 mph. Luckily it missed the car behind and landed on the grass completely undamaged. Turned out that the rubber bonnet latches I fitted (picture below)to get through the SVA just weren't up to the job. The front ones popped open, the bonnet lifted and the back ones just gave way. We finished the track evening with the bonnet gaffer taped on !!

I really want to fit some proper fasteners that I can secure with an "R" clip. the question is can I get some that will either cover the existing mounting holes or re use them.

I'm not running the risk of that happening again. Next time the car behind might not be so lucky.




[Edited on 21/6/05 by givemethebighammer]
Rescued attachment bonnet_latches.jpg

I used case clips priced £1.99 a set with a hole ready made for an R clip, not rubber covered though but that shouldn't matter now.

It's suprising how many people have had problems with these things. There is a preset distance to generate different forces on the mating surfaces which I received from the manufacturer. Those catches can withstand 45Nm! My guess is that the clamp and clasp are not far enough apart and as a result were too loose. I'll try to scan in the graph of forces I asked for with our clamps.

Thanks Hellfire

I put them on with the distances specified with the catches. They were OK when I first did them, I guess something may have stretched. I had also noticed that they tend to loosen slightly on hot days (black rubber is going to soften slightly). Anyway I have decided you can't get much more secure than using a metal catch and "R" clip. I just need to find some that fit over the existing mounting holes.

thanks again

No problem GMTBH

stick mine down with gaffa tape,just in case on track days.

I used some adjustable ones from Merlin Motorsport. Can be locked with "R" clips but self lock even without, and allow about 20mm of adjustment so might work to cover your original holes.

I have these rubber catches, and I'm planning to replace them very soon.

Doing 70mph and seeing the back of the bonnet lifting in the centre due to air pressure in the engine compartment is unnerving!

David

What about using Dzus fasteners? These are sva ok (though that is of no relevance now I know) and are positively locked, and in shear anyway. And they look good!

The biggest bonus of the conventional latches is their ability to 'pull down' when they are closed, holding everything tight.
I have seen Dzus on 7's though, and they do look tidy. I believe that Westies use them at the back of the bonnet - the front is held down with pegs that locate on the nose cone (I believe).

DJ

DONT FEEL BAD ABOUT THE BONNET COMEING OFF ONCE.......I KNOW OF ONE CAR THAT HAS LOST ITS BONNET 3 OR IS IT FOUR TIMES!!!!

We lost our bonnet with these rubber catches as well about 3 weeks ago,
looking back it was probably because they weren't spaced properly and put on in a hurry as they were cobbled back on to the MOT carb bonnet.

We Had Dzus fastners b4 and they started to lift at speed as they rode up the spring clip they lock onto,
and the paint always chipped off when operating as the zinc coating looked pants.

Unlucky, or lucky it wasn't that badly damaged seems there flying off nearly as often as cycle wings!

I inted to fit pegs to the front of my bonnet like Westfield do to stop the front wanting to lift at speed.

When they fly off is it front or back first?

Think it was Tifosi who had some really neat panel fixings at Stoneliegh, about £30 a pair If I hadn't used Dzus fasteners I would have gone for them , suspect when I redo my bonnet that is what I will use . May be worth checking thier website?

With the Dzus it was the rear of the bonnet that would lift as the whole bonnet must have been sliding backward and up on the spring clips they lock onto.
But fair play to them they never let go!

With the rubber catches I believe it was the front that went first or even 1 front corner as 1 hinge bar was ripped from the rubber latch.
possibly aided by the nose cone pushing up as this pushed up and forwards after the bonnet had flown off.

Try the Aerocatch for size - they are really bling and lockable too!


[Edited on 22-6-05 by RazMan]

Thats the type sold by Tifosi , looked to me to be very neat and secure if not exactly cheap.

I have these catches on my car , but also stuck an alloy U section to the back of the bonnet to locate under the scuttle lip so far have had no problems.
Paul.

I don't feel bad about having lost the bonnet as this time there was no harm done. However if it had hit the car behind (caterham) it could have done some serious (possibly fatal) damage. The thought of it happening on the M1 does not bear thinking about. I fitted the clips as per the instructions making sure I spaced them correctly. Why it came off I don't know maybe a combination of vibration, heat, excessive speed and pressure in the engine compartment ? Anyway I'm going to fit some steel fasteners with "R" clips to ensure it doesn't happen again. Northy the front broke loose first.

I have looked at several types of fastener. I think one of the two below look up to the job. Anyone used either ?

sorry to rant but not an experience I want to repeat.
Rescued attachment catches.JPG

Should be fine. However, the aerocatches are a superb piece of kit.

thanks Steve. the aero catches look good, but not so easy to fit. The steel over centre type seem the logical thing to use for me. I am thinking that the adjustable ones are the most sensible option as they are easy to adjust if they get loose.

The one on the left is like mine. They have a hole in them and the R clip pushes through locking them down. I only put clips in the fronts.

[Edited on 22/6/05 by Peteff]

I might point out that a low flying bonnet is a traditional seven pastime invented by the low flying mag readers.

Sorry for arriving late but I managed to miss this thread when it happened.

The same thing happened to me using the exact same catches. I was very precise about placing the catch and holder mechanism, and it felt tight and seemed to operate OK, but went after a while.
Doing about a fair bit up the road, I saw the drivers side of the bonnet flap up once at the front, I slapped on the brakes, but the bonnet had dissappeared about 30ft up in the air and landed (painted side down) on the road. I had to respray the bonnet. Luckily no-one was hurt.
I replaced the rubber SVA catches with proper stainless steel spring catches. No trouble with these whatsoever.
I have known other folks who have lost bonnets and all have been using these SVA friendly rubber catches. These have been the only commonality in the failures.
IMHO these aren't up to the task EXCEPT for passing the SVA, and then should be replaced.
They are dangerous. Again this is only my opinion. Some people have used them and found them OK. But IMHO the failure rate is far too high.

alister,

The more I talk to people about the incident, the more people seem to have had the same thing happen. I'm just glad no one got hurt. No warning with mine. But I guess at 90 mph it was going to happen very quickly anyway. All fixed now stainless catches and r clips all round. See post "Belt and Braces".

SVA compliant, ha ! you won't cut your finger on the catches but the bonnet may take your head off when they let go !

[Edited on 1/7/05 by givemethebighammer]

With the colour scheme of our car being Yellow and black, does anybody know of any alternative catches in black?, because they do sound to be a weak point.

We had Dzus painted black before but the paint chipped off over time and due to how they open.

Or even any suggestions on how to do it in another way with no visable catches at all.

Maybe some vents in other areas like the side pannels would relieve the pressure better and stop it trying to lift the bonnet.

The side of my car are polished (not too well )
aluminum so the stainless catches don't look out of place. I guess you could get them anodised though? (the catches that is).