A8 soft close boot / trunk failure [Archive] - Audi Forums

: A8 soft close boot / trunk failure


Gridders
04-11-2013, 05:55 PM
Posting my bonnet failure has reminded me to post this.

My A8 has power boot with soft close function. One day, out of the blue, the boot failed to close and just kept opening again. Eventually I slammed it shut but clearly all was not well.

A few days later, fearing the worst, I set about investigating and found the following, which was a simple, mega cheap fix but would have been a /$100's bill at a dealer.

The soft close motor is separate from the main closure motor. It is activated by a microswitch in the boot latch which closes when the latch hits the locking pin on the boot slam panel. On most cars, this pin is in a fixed position, but on the soft close A8, it sits on a slider and is held in the open position by a small coil spring under tension. Once the boot latch closes, the microswitch is activated and the motor operated, pulling that pin down into the car and thus soft closing the boot.

Access to the pin and associated mechanism is easy via removal of the boot rubber seal and black plastic slam panel trim, then a few 10mm (I think) bolts/nuts. I took mine out and immediately noticed that the small spring had snapped. Its about 5mm diameter and about 30mm long and hooks onto obvious points.

the result, the pin was too low for the latch to reach on the main motor and the boot couldn't close so just re-cycled open.

I had to buy a huge box of different sized springs (handy to have you know) for a whole sum 5 ($7 approx) The actual spring costing i the region of 2.5 pence (I'm guessing at 5c) and took 30 minutes at most to fix.

A word of note though, make sure the boot (trunk) rubber seal is properly re-seated or the boot wont align properly when closed and while you're at it, check and lubricate your boot hinges. Some have steel pivot pins that are prone to corrosion and seizure that ends up costing a fortune in boot motors.

Happy motoring.