Bonnet Catch

[gruffalo]

Car just decided to not lock the bonnet down properly, the knob just keeps turning through the locked position and goes all the way round to unlocked again, any one had this before?

[Ireland]

Is the knob turning and nothing happening with the locking rods?

If so then it's probably that the grub screw that holds it together has loosened.

[gruffalo]

No, the rods move and the bonnet locks but it keeps turning all the way to open again.

You can stop turning the knob at the point of max resistance and it is nice and firmly closed but when driving it will just vibrate past that point and flop towards open again.

[kevin63]

Sounds like the spring loaded grub screw is not locating in position to me. Screw the grub screw in slightly (if it's still there) but don't go too far as it will lock the knob in position. A 5mm Allen key will be required.

[pmessling]

is there not an allen bolt on the back of the knob that stops it going round and round? A stop?

[Mad Mark]

From memory there is a small allen/grub screw type thing that screws onto a spring with a ballbearing at the other end. This ballbearing locates into a recess causing the knob to lock in to place. chances are the BB has got jammed slightly or the BB spring and washer have fallen out.
It's easy to dismantle and put back together again.

[tur8o]

i havent looked closely but isnt there a roll pin thingy sticking out of either side of the knob that stops it turning too far? also, on a similar topic does anyone have any tips for stopping the the rods etc rattling/vibrating?

[gruffalo]

tur8o said:

i havent looked closely but isnt there a roll pin thingy sticking out of either side of the knob that stops it turning too far? also, on a similar topic does anyone have any tips for stopping the the rods etc rattling/vibrating?

adjust the rods a bit to make them move out further, the increased pressure on the rods holds them tight, well it did on mine.

[gruffalo]

thanks everyone for your input, guess I will spend some time under the dash this afternoon.

[Mr Cerbera]

The Knob itself is attached with a very small Allen screw for attachment/removal.

Above that, in relative terms to the centre of the Earth, is a Collar which has the 5mm Allen screw in it. It has two indentations which are located by a sprung ball-bearing located in the recess of the housing.

With the collar removed, the shaft will turn freely from one extreme (rods withdrawn and therefore bonnet open), through its middle position (rods fully extended and bonnet locked) to the other extreme (rods withdrawn and bonnet open again).

You have to work out a central postion to lock the collar on the shaft where one of the indentations gives you a locked bonnet(depending on whether you want to turn it anti- OR clockwise to open it). The other position will automatically engage at fully open position.

I now have a headache just trrying explain that so here are a couple of pics to (hopefully) help.

Good Luck !


Sprung Ball bearing in housing



Adjustable collar

Edited by Mr Cerbera on Sunday 4th September 16:21

[gruffalo]

Sir you are a star, will have a look one evening as rain stopped play this afternoon.

[gruffalo]

Well I can't get it to lock, it seems like I may have lost my ball and a spring, any ideas on sizes needed to replace?

[FarmyardPants]

Bump for browrz

[gruffalo]

Got mine sorted out by taking it to the garage and they took it apart and got it all working again, seems it was all there just not quite in the right place to operate correctly.

My spring and ball were pushed to far in or something like that is what they said.

[browrz]

Mr Cerbera said:

The Knob itself is attached with a very small Allen screw for attachment/removal.

Above that, in relative terms to the centre of the Earth, is a Collar which has the 5mm Allen screw in it. It has two indentations which are located by a sprung ball-bearing located in the recess of the housing.

With the collar removed, the shaft will turn freely from one extreme (rods withdrawn and therefore bonnet open), through its middle position (rods fully extended and bonnet locked) to the other extreme (rods withdrawn and bonnet open again).

You have to work out a central postion to lock the collar on the shaft where one of the indentations gives you a locked bonnet(depending on whether you want to turn it anti- OR clockwise to open it). The other position will automatically engage at fully open position.

I now have a headache just trrying explain that so here are a couple of pics to (hopefully) help.

Good Luck !


Sprung Ball bearing in housing



Adjustable collar

Edited by Mr Cerbera on Sunday 4th September 16:21

I have been playing with this mechanism on mine after several bonnet popping moments. The pictures were very helpful before disappearing backwards under the steering column.

But I have a question; the main knob is sprung so you can pull it toward you and it (reluctantly) pulls back against you (there is a small compression spring around the shaft, on the engine side of the bulkhead).

So how is this whole mechanism supposed to work?;
Is the ball bearing supposed to roll around the outside of the collar before dropping into one of the grooves (and you can see the marks where it has done this in your photo).

OR, are you supposed to pull the whole knob toward you, then rotate it and then push it back toward the engine and allow the sprung ball to side UP one of the grooved channels?

Looks like from the thread people think the first option, but having set it up like that I am left wondering why the whole thing was sprung, and I think the second option would be more elegant and less wearing on the collar….but I haven’t tried it yet.

Thoughts?

[gruffalo]

No pulling of the knob is necessary though can be quite pleasing, should just turn and the spring pushes the ball into the slot to stop it going to far.

Possibaly the most wrong sounding but correct posting I have ever made.

[FarmyardPants]

You're not suppose to pull the knob, just turn until it clicks. You shouldn't be able to turn it beyond it's intended rotation, it should click and then not turn any further.

[browrz]

Okidoki, less pulling and more twisting.
Now I think I'd better sign this thread off!
Cheers

[ukkid35]

I wish I'd seen this a couple of weeks ago, that would have saved some of the comedy paintwork coming off on the carpet tape that I used to sure the bonnet in an emergency.

I have since spent several hours upside down with my head in the footwell. I found that the collet grub screw was missing, nothing lined up, the ballbearing spring grub screw was completely obscured by the carpet.

I determined that:

• the pull/push spring is a bit of a red herring
• the collet should be fully inserted but this can't be done without loosening the the ballbearing grub screw
• the groves in the collet are insufficient to locate the mechanism in a locked position
• if you remove the two bolts holding the boss with the sprung ballbearing the boss still won't budge
• if you replace the collet grub screw with a bolt you can make this the back stop providing you locate it in the correct orientation

Only tested the to about 130mph, but it's not budging now.

[Mark.]

ukkid35 said:

• if you replace the collet grub screw with a bolt you can make this the back stop providing you locate it in the correct orientation

Only tested the to about 130mph, but it's not budging now.

Mine has a bolt too - must be a mod

Can confirm speed test to mildly above the 130 too.