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VW Golf MK5 - Overhauling a seized bonnet lock

Article Date: 26/08/16

With my MOT looming on my car, I didn't want to run the risk of my cars bonnet lock failing the MOT. Recently when you try to open my bonnet now, you have to really pull hard on the lever to open the bonnet (almost as if the cable will snap), it will extremely stiff and I didn't want the risk of the car failing the MOT because of it. A few years back, I had a problem where the bonnet wouldn't shut properly on my Golf MK5, this was because the lock had failed. I replaced it in my bonnet catch article.

I didn't want to spend another £40 buying a new bonnet lock, so decided to see if I could overhaul it instead, as the bonnet lock hadn't completely failed, but was showing signs of all the grease drying out on the lock because it was stiff. I believe realistically this should be undertaken once per year as part of a maintenance schedule. The bonnet is susceptible to all sorts of rubbish and liquids from the front of the car, so corrosion can build up. Once it gets into the components it just gets worse over time.

Regreasing the bonnet lock seemed liked the solution, so here's how I went through sorting it out

bonnet Loosen the two screws next to the headlights. They are T20 torx screws. Once they are loosened simply lift up and unclip at the connectors by the vents next to the lock
loosen-tension

Before you disconnect the bonnet lock you will need to release the tension on the lock and handle. This will make it easier to remove it

Unclip the cable housing from the bulkhead above the headlight. It simply pops off

You then open it, by inserting a screwdriver in the following place. Just wedge a thin one in and pry upwards, or twist it to open.

tension-opened Once the cover is open, simply unclip the bonnet lock from the mechanism within. There's a metal grommet which attaches to a hole within the actual connector on the spring.
unclip-alarm

Before removing the entire lock and it's assembly make sure you disconnect the bonnet alarm. If you snap the wires the chances are you will need a new lock entirely.

It's held in a holder underneath, you will need to look over the bonnet as it sits behind the radiator next to the headlamp. It simply unclips from here.

To disconnect the alarm, simply put a screwdriver at the end and twist, or at the front slide it down the long edge in between the gap and lift the clip underneath

You will need two screwdrivers (or torx) bits to remove the bonnet lock on the Volkswagen Golf MK5.

The bonnet lock screws are T27 in size, although I didn't have mine, so I used a T25 bit which worked fine. Just watch out when tightening it up

The two screws on the right are the longest ones, remember this when fitting

bonnet-lock-removed

This is the bonnet lock after it was removed. This was after 3 years of being fitted to my car you can see how rusted and crappy it's become. Look where the bonnet handle connects, it was caked in rust

This is what releases the lock, if it sticks your screwed

lock-removed2 This is after I had initally removed the lock, personally I think when you overhaul it you should remove the entire unit so you have something to work with. The unit appears to be sealed together so it can't be dismantled, the only thing you can do is clean out the crap and regrease. This worked for me
lock-removed-3 As you can see the lock is pressed together, unless you want to repress the joins you simply have to clean it up as best as you could
rusty-cable Unclip the old connector, you may need to free it up as it will be rusted inside the housing
carlube-grease

Don't use WD40 for your bonnet lock. It's rubbish

Use a proper grease designed to lubricate and stay slippy. Lithium Grease is generally regarded as one of the best. I bought this entire tub for about £6 from eBay, it will last for ages and suitable for all types of jobs

Before you start regreasing the locks use a can of brake cleaner. It does amazing at clearing off the old built up crap on the bonnet lock and will help get rid of any build ups before you regrease it.

lock-greased

Once the brake cleaner has been used, apply grease generously throughout the lock and springs, making sure you get in every nook and cranny.

I made sure that I used a screwdriver and prised each spring open, also lifting up the lower spring and get under it

lock-greased2 Pay special attention to this area where the cable connects to. You should be able to pull this up as if it was being opened, but if the lock doesn't immediately spring back down it's not clear yet
lock-greased3 This is also where the bonnet connects, make sure there is adequate grease for it here too

Once you have assembled the bonnet lock, I suggest taping up the wire on the plastic housing. Then insert the wire through the holes in the bonnet and reconnect them to the tensioner. Leave the bonnet grille off for the moment and test with it.

If the bonnet opens and closes fine, then your OK, just reconnect the alarm wire then simply put the screws back in. If the bonnet lock doesn't close and jams, you will need to remove the lock and find out what is causing the problem.

If there is no tension to the wire (most likely) then you problem will be because either the guide rail has come off or the tensioner wasn't fitted correctly into the housing