Sticking Bonnet

120,600 miles, 22nd October 2010

Update February 2012. This repair wasn't very successful. Read my article about fitting a replacement bonnet latch.

I had heard of fellow Mk V Golf owners having problems with their cars' interior bonnet release lever becoming very stiff, sometimes resulting in either the lever breaking, the cable snapping, or both! The bonnet release on my car was becoming noticeably stiffer and only a few days earlier I had had trouble getting the bonnet to close fully. Therefore, after my success at replacing my car's original battery, when I again had trouble getting the bonnet to close fully, I thought that repairing a sticky bonnet release would be another easy task. I was wrong!

With the bonnet open, I found I could easily remove the front grille (the bit with the big VW emblem on it) by just removing two small torx-head screws. The grille then unclipped easily enough. I then saw the 3 larger torx-head screws/bolts which held the bonnet's locking mechanism in place. They came out easily enough. I could ease the lock mechanism up to get access but not much as the release cable and and alarm bonnet switch wiring were still connected.

Viewed from front of car, bonnet locking mechanism, still attached to cable & wiring, exposed.

Looking from the back I could see rust at the very end of the release cable. This rust was beginning to spread and jam the lock mechanism which explained the stiffness.

Viewed from rear, bonnet locking mechanism showing rust at end of release cable.

By squirting lots of WD40 over the rusted area, leaving it to work and then raking out bits of rust using an old screwdriver, I was able to clean it up a bit. It was impossible to get rid of all the rust. I then applied a bit of oil to try to prevent further rusting.

Securing the lock mechanism back in place didn't initially appear difficult at all. I then closed the bonnet, pulled on the bonnet release lever but the bonnet stayed firmly shut!

Fortunately I hadn't replaced the front bit of the grille so I was still able to get access to the 3 bolts holding the lock mechanism in place. I removed them and carefully lift the bonnet (which is still engaged with the lock mechanism) just enough to be able to poke a screw driver into the lock, spring it open and release the bonnet. Phew!

Turned out the release cable sits in a guide which has to be attached to the lock mechanism for it to work. As I had eased the lock mechanism back into place the release cable had unclipped itself from the lock. Without the cable and guide being attached to the lock, pulling the bonnet release just flexes the cable, it doesn't spring the lock.

Knowing this, I tried for quite a while to push the lock mechanism back into place whilst keeping the cable and guide attached. There was not much room to work with and I found this impossible. Fortunately, after much trial and error, I found that you could ease the lock mechanism roughly into place, move the cable guide into position just underneath it and then, with an Allen key (or any small L-shaped piece of metal) pull the guide up where it clips onto the lock mechanism. Tighten the lock mechanism's screws/bolts, give it a test or two before you replace the front grille and your car's bonnet release is as good as new!

Update February 2012. This repair only delayed the rust for just over another year. I eventually needed to replace the lock mechanism to fix this problem properly. It turned out to be a cheap and easy job. Read my article about fitting a replacement bonnet latch.

I suspect over time the bonnet release will again start to stiffen as the rust at the end of the cable eventually returns and begins to jam the mechanism again. I will see how long my repair works but I may eventually have to replace the last section of the release cable (the cable has an easily accessible joint just behind the driver's side headlight). Hopefully I can buy just that last section of cable. I don't think this would be too hard to replace.

It is important to realise that you can only do this repair/maintenance whilst you can still open the bonnet. If you wait until the lock mechanism jams completely or the bonnet release cable snaps whist the bonnet is shut, you will probably have to break (and subsequently replace) the front grille in order to get at the bolts holding the lock mechanism in place. Worth doing as soon as you notice the bonnet release becoming stiffer.

Final note. I found it hard to detach the wiring to the alarm's bonnet switch in the lock mechanism and so it was attached all the time I was moving and cleaning the lock mechanism. These wires are quite thin and you risk breaking them. If this happens, your car's alarm will probably fail to arm because it will think the bonnet isn't shut properly. Didn't happen to me fortunately (although I did notice some wear) but you've been warned.