Bonnet Catch Won't Open

E

exdos

Senior member
My Z4MC's bonnet has refused to open today. I've tried all the usual tricks, but no joy. I'm going to remove the access panel to the headlamp to see if I can sort this out from inside. I know the mechanism is very clean so it's not gummed up with muck. I've posted the photo of my car and could anyone tell me if it is missing any form of rubber "stops" which I would normally expect to be present. To me, it looks as though there should be something in the hole in the black panel which I've indicated with the green circle.

Thanks for any help anyone can give me.

openbonnet.jpg
 
Zed Five said:
Have you tried getting a friend to gently press the bonnet down with plams of hands as you pull the cable?
Click to expand...

Yes, enlisted the wife. I'm now awaiting the "To Do" list as the price I'll have to pay. :roll:
 
exdos, looked at mine just to be sure, you don't appear to have anything missing. The only rubber stops are either side of the long rubber strip along the top of the bumper that is part of the metal strip holding the bumper in place. They have spring-loaded screwed-in shafts that push the bonnet up when the front catch is manually released by you - your photo shows both of these stops, and you have both catches. You've put an arrow to one catch, the other is just in front of the washer bottle.

Perhaps one of the Bowden cables (right term ?) that triggers the side catch release has gone ?
 
How crazy, I've just got this exact same issue.

Really need to know how to address this since I gotta top up my oil.
 
Here's a pic of my catch on the same side so you can see the cable mechansim. Upside down, sorry - but having had more of a look you should be able to get to it through the access panel... Might need the hands of a child to do anything though...

IMG-20130110-00112.jpg


The cable looks and feels like it is slotted into a silver bracket, kind of like the way brakes work on a bike. If the cable has slipped out of the bracket there will be no tension, so I guess it won't pull the catch mechanism when you press the button to open it ? OR the little bullet shaped slide that actually pulls the catch open has gummed up...
 
When you say the bonnet doesn't "open", do you mean it doesn't pop up or that once it's popped up, you can't get the catch to release the bonnet?
 
I'm sure I read somewhere that a sharp bang on the bonnet while pulling the handle inside is the way to fix this.
 
Bing said:
exdos, looked at mine just to be sure, you don't appear to have anything missing. The only rubber stops are either side of the long rubber strip along the top of the bumper that is part of the metal strip holding the bumper in place. They have spring-loaded screwed-in shafts that push the bonnet up when the front catch is manually released by you - your photo shows both of these stops, and you have both catches. You've put an arrow to one catch, the other is just in front of the washer bottle.

Perhaps one of the Bowden cables (right term ?) that triggers the side catch release has gone ?
Click to expand...
Bing, Thanks for confirming that I'm not missing any rubber stops. Are those spring loaded shafts you mention not the bonnet sensors for the alarm?

I was working on the air-intake system the other day and I'm wondering if what I've done has fouled the cable, I didn't take too much notice at the time.? :cry: On the positive side though, my air intake mod has been a success. :)

Thanks for your photo of the catch; that's a big help, I now know what I'll be feeling for.:thumbsup: (no smutty comments from anyone required!!!!!!!!!)
th30d0r3 said:
How crazy, I've just got this exact same issue.
Click to expand...
I intend to look at this tomorrow, so I'll report back and take a few photos for you. :thumbsup:

Redzedfour said:
The black plastic panel covering the radiator is missing or did you take that off :?
Click to expand...
That photo was taken sometime ago when I was doing something else to the air-intake. You see, I'm obsessed with air-intakes and devising ways of improving them. :oops: :smart:

Adelphi2 said:
When you say the bonnet doesn't "open", do you mean it doesn't pop up or that once it's popped up, you can't get the catch to release the bonnet?
Click to expand...
The catch releases and the bonnet pops up on the right side, but nothing is happening on the left and it remains locked.
daz05 said:
I'm sure I read somewhere that a sharp bang on the bonnet while pulling the handle inside is the way to fix this.
Click to expand...
Tried that too. This is what is now making me think what I did the other day has fouled the mechanism/Bowden cable. Bing's photo of the catch and the short length of cable appearing from the sheath suggests that it wouldn't take much to get in the way to restrict the movement of the cable.
 
Exdos, the sensor for the alarm is the black plastic box just behind where the firewall braces meet at the back of the bonnet.

One of the screw-in springs on mine pushed all the way through and i had to replace it, so they can fail. However they are not attached in any way to the side catches so I'd suggest that's not the problem.

When you say 'left' do you mean in the photo, or looking forward from the drivers' seat ? Just confused because the intake system is on the right in the photo - my photo is of the left hand side from the perspective of your photo so you need. O reverse it in your head for the other side. I guess it is possible you knocked the cable out of the retaining clip if you are talking about the intake side, but I did give mine a wiggle and it is pretty firmly held... By a plastic grommet, which I suppose could perish.

Shall stop withering now. Happy to help :thumbsup:
 
Bing In my photo, there's an alarm switch at about 4 O'clock in the green circle. That's the part I thought you were referring to as a spring?

When I say "left" I mean Nearside/passenger side just in front of the air-filter box. Once I'd seen your photo of the catch it became much clearer to me, that what I've done is most likely to be the culprit. :( In any event, I'll discover a way to access the catch from inside and then it'll be a "fix" that every one should be able to use. :thumbsup:
 
exdos, that's not an alarm, it's the spring / stopper I am referring too. When you finally get into your engine compartment you'll find it is a rubber bung with a thread cut into it and the spring loaded stopper screwed into the middle. There's nothing attached to it - both sides simply push the bonnet up far enough for you to get your fingers under to the centre catch.

Hope you get it sorted :thumbsup:
 
I've taken the nearside wheel off and removed the plastic panel from the wheel arch liner and the bonnet catch is accessible this way. :happyclap: :D

I pressed on the lever arm and the bonnet opened. :thumbsup: Since it was easy enough to undo this way, after lubricating the catch, I closed the bonnet and tried releasing it again, and it still wouldn't open. The cable is not fouled by any of my work, so I think the cable might have broken, so I'll investigate further. The main thing is that I've been able to open the bonnet and so I can now repair at my leisure.

Now that I've found this out, it should be possible to get access to the catch without removing the front wheels.

IMG_0795.jpg


Bing I've taken a photo of the part which I think is a switch for the alarm system. It looks very much like a similar part on my Z3MC which I know for sure is an alarm switch (common problem on that car). I've not undone it to see if it has a wire connection to check though. As always, I'm prepared to be wrong.

IMG_0796.jpg
 
Glad you managed to open it without too much hassle, my father had the same problem with his Z3. Clearly you've worn through the cable by opening the bonnet too often in order to fettle the induction system :P

I must say, like Bing, I thought the switch for the alarm was at the back of the engine compartment and that which you have photographed simply adjusts the height of the closed bonnet so it will sit flush with the wings. I'll have a look at mine when next I venture into the garage.
 
That's just a bump stop. as Bing and BMWZ$MC have said the alarm switch is between the braces on the bulkhead.
 
Glad to be corrected on the bonnet stops :thumbsup: :thumbsup:

BMWZ4MC, I think you're probably right: I do open and close my bonnet more than most will. However, a small price to pay. :wink:
 
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