I think the problem with that is that the air path round the radiator is blocked on the post-26 body so there isn’t room for the springs there.
For years I have had to pull one catch and press the other side of the bonnet to get it to rise and then ‘bounce’ it while pulling the other catch to get that to release too! Many years ago I fitted a new square-section foam rubber for the back of the bonnet (hood) to rest on and it used to spring up readily but not any longer.
My nylon screw heads (in the pivot area) are pretty flat now so perhaps the bonnet has moved back and is jamming. I’ve been meaning to add springs to help it release for years so perhaps this summer…
I had the same problem and tried the usual remedies but nothing helped. The bonnet lifted a small amount but the catches would reengage when I let go of the bonnet release.
Eventually I decided that the spring needed to be a bit stronger.
I bought a length of catapult elastic from eBay. (Apparently fishermen use catapults!) I threaded it down the centre of the spring, round the bottom wire, and then back up the centre. I clamped the two bits of elastic together at the top using a wire rope clamp from Screwfix.
It took a bit of trial and error to get the length correct but this beefs up the spring a bit and lifts the bonnet clear of the catches.
After a few months, the elastic appeared to relax a bit so I adjusted the wire rope clamp.t
You don’t have the correct Hook on the front of the Bonnet. I think someone broke the original and did a quick bodge. You need to make a correct Hook and get it brazed to the cross bar.
The correct Hook is long so it is further from pivoting axis. Giving spring better leverage to open Bonnet
Alan
The hook arrangement in Lotus54’s photos is exactly the same as that on my '67 S3 i.e. factory fit. The later S4 bonnets have a glassed in steel stiffener rail around the front and sides (S3’s are braced with rope tube glassed centrally into the under side of the bonnet to form a large X shape). Welded/brazed to this perimeter rail is the longer version hook that does indeed put it farther forward of the pivot point.
Hi Mike,
I’m just going by the Sprint i had.
I would make a long Hook for better mechanical advantage. Like you say could be glassed in neatly. I don’t have photo of my Sprint and now i’ve sold it.
Maybe someone has a photo, easy to make a Hook.
Alan
Hi Alan,
Until your earlier post I had never really thought about the mechanical advantage of having the hook farther forward, I just assumed that the bonnets were just “different”. The hook on my S3 was actually broken so I made an exact replica. I now know what to do if it needs modifying to get a better lift from the spring.
This was the condition of the hood – err, bonnet on my Elan when I got it. The catches would release but the hood would not move, so the catches would re-engage. I cleaned all of the gunk off the nylon screws, replaced the worn out stuff up there too, and then did your trick of putting a small block of stiff foam at the edge of the bonnet opening just next to the catches. Now the bonnet pops open nicely, so long as I pull both releases at the same time. I can see that the foam will not last forever though.
I think the real issue is that the spring is justbarely up to the job of popping the bonnet up under the best of conditions, and those conditions were 60+ years ago. I do like the idea about moving the spring mount point forward though; that should provide some mechanical advantage.
I agree with Alan and others. The hook must be wrong (too short) - the spring needs more leverage not more tension.
My bonnet, about which there is nothing special, pops up six inches or so with no problem. With greased skids it leaps up rather alarmingly a foot or more.