Trunk (Bonnet) hinge play
 

I was muddling around in my trunk yesterday and I noticed that on the extractor vent outlet under the rear window the paint had been scraped off of a couple of the little bridges / grills in the outlet opening. A little more examination showed that the front edge of the trunk lid was just grazing over a couple of the bridges as the trunk lid was closed. The little bridges have a slight outward bulge to them and the amount of bulge is clearly non uniform since the trunk lid front edge was not contacting the bridges on either side of the scraped piece and the distribution of the scraped bridges was rather random across the extractor vent opening.

I did an immediate fix to the problem by positioning the trunk lid on its mounting holes so that the lid sat further back about 3 mm which eliminated the contact problem. However, the back edge of the trunk lid is no longer nice and flush with the back of the rear 1/4 panels. While doing some open and closed testing on the trunk lid, I noticed that as the trunk lid is approaching the closed position, about 50 mm from full closed there is a fair amount of fore - aft play in the hinge mechanism. As you are closing the lid there is a slight natural tendency to push a little forward on the lid and the play in the hinge mechanism is what allows the contact to occur. If I very carefully lower the hood and pull back on it ever so slightly the contact does not occur. With the lid just held barely open (latch has not engaged) I can move the lid for and aft about 3 - 4 mm quite easily. I tested the hinge pivots when the lid was fully open by pulling up, down and sideways on the lid and the and there was no obvious slop in the mechanism. Given that the lid does not get opened and closed a lot, I would be a bit surprised by significant wear.

I am curious as to whether other 142 and 144 owners have similar for - aft movement in the lid as it approaches the closed position? Given that signs of wear were not obvious, I am wondering if the kinematics of the hinge mechanism conspire to amplify the normal clearances in the pivots - there are 5 pivots in the one linkage so 5 small clearances might up adding to a lot of slop in a particular alignment. The intent of my question is that if this for aft movement in the lid is a normal feature, I am not going to pursue new replacement hinges as a possible fix.

It occurs to me that the other possible fix is to take a brass drift covered with a couple layers of leather along with a ball peen hammer and massage those high bridge points in the vent opening a bit so that they are lower. The paint already requires a little touch up so as long as I don't go extreme and flex the steel so much that the paint cracks I should be good - unless the contact point then moves to a new spot!

Oops! Boot not bonnet - pardon my English.