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MG MGB Technical - bonnet problems

i can't work out how to adjust the bonnet , clicks in to position but there is still up and down play .there is a adjuster nut in the spring but can not work it out , the mechanism works fine and the bonnet is nice and sguare .


The adjuster nut is really a lock nut. The latch pin (dart) screws into the bonnet and the nut you can see is used to lock the latch pin in place.

To adjust, you'll need to slacken off the lock nut (you can usually force a spanner between the spring coils to get at this) then put a screwdriver in the slot on the pointed end of the latch pin and turn to adjust in/out. Might need a bit of trial and error, but you should be able to eliminate the play you've got.

Hope this helps


Is it worth removing the grille/rubber bumper before adjusting just in case the bonnet jams in the closed position? (I haven't checked my BGT, but I know that's the case for the MGA)

Neil McGurk

Why are you looking to adjust it? If the shut line looks nice and it is secure you do not need to do anything. There was an article (Safety Fast I think) where a midget owner adjusted the catch so it it closed with no play, and it popped open after going over a bump, and continued to do so until he put it back in the middle of its range. This is a potentially life threatening failure. There is a backup catch, but why take the chance on it working? It seems the catch is designed to allow flex in both directions. I also keep both the main and safety catches greased on all my cars. Not everyone does this sometimes you see show cars with their bonnets propped open and not a trace of lubricant near the slam panel, agsin if there is no problem and the apint is 100% everywhere its OK, but why not just lubricate it all and be certain?
Stan Best

the bonnet was removed for paint , and thats how it came back !


I'd certainly follow what Neil says and remove the grille before you attempt to adjust the bonnet just to be on the safe side in case things get stuck!


Hi Daz, yes if it's been removed then yes you will need to trim it to best postion, just dont make it so tight it cant wriggle a bit as the car flexes. When I did mine I screwed the bolt out a way and copper slipped the exposed threads befaore setting and locking it.
Stan Best

I'll add another step to the above...I learned this after having the bonnet come up on two of my MGB's (one at 70MPH on a motorway in the rain!!)...add a small leather strap to the front...sold by Moss or most any MG parts houses...good insurance!!

Bob Dougherty

Daz, the bonnet should be just touching the two rubber bump stops on either side when the center latch is made. Close the bonnet and lift it against the latch and then check the fit between the bonnet and wings. If the bonnet is high, then adjust the center pin of the latch downwards until the bonnet and wings line up, then adjust the two bump stops upwards until they just touch the underside of the bonnet bracing. Bumpers are shown circled in the attached photo. These may have to be shimmed or trimmed slightly for best bonnet fit.

Bill Young

It *should* spring up and down when fastened, that is how you get the correct vertical positioning of the front of the bonnet.

It can pop open if the head of the pin is worn or the latch or cable is sticking, in the forner case simply turning the pin 90 degrees whichever way suits the alignment best should put an unworn portion of the pin into play ... unless a PO has already done it the other way.

The rubber buffers should fit inside the grooves on the sides of the bonnet, they are not there to control bonnet height as there is no adjustment, they stop the sides of the bonnet flapping up and down.
Paul Hunt

Hi Daz,
I think this has been touched on already but make sure the rubber bits are in place...two bits on the top of the grille and some bits on the inside lip on the front wings/fenders...

This thread was discussed between 18/10/2008 and 21/10/2008

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