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Removing broken self tappers.

Posted: Tue Sep 07, 2021 3:39 pm
by DaveEFI
Had new wings fitted a few years, and they used self tappers to secure the top of the plastic spoiler to the lip at the bottom of the front wing. (The original fixing was a small captive bolt in the spoiler and a nut inside the wing lip, but these shear, and I'd replaced them with M4 stainless steel nuts and bolts - fiddly to fit but worked) The new wings don't come with the hole for this bolt. Had to remove the spoiler and undertray to fix the windscreen washers, and what I'm left with is the thread of one of the self tappers sticking out of the wing which won't budge with Mole grips. And on the other side, the self tapper jammed in the spoiler (I'd guess there is a steel reinforcement plate inside)

Can't use heat on the plastic spoiler. Or really on the wing, as I don't want to damage the paint.

The spoiler is also a very difficult shape to put in a vice.

The bit sticking out of the wing didn't have a head on it. Almost looks as if it was inserted from the back and welded in place (lots of underseal inside the wing I don't want to disturb)

I'm rather at a loss. :D

Re: Removing broken self tappers.

Posted: Tue Sep 07, 2021 6:55 pm
by stevieturbo
pics ?

can you grind them down in lieu of actual removal ? Hammer and punch them out ?

Re: Removing broken self tappers.

Posted: Wed Sep 08, 2021 9:11 am
by DaveEFI
Was really just having a vent.

Remembered I had a small Stilson, so found a large washer that fitted to protect the paint, and got it out. Turned out to be the thread of a self tapper where the head had sheared off. Presumably when being fitted. So pretty rubbish self tappers - not that hard. And so it proved - with the spoiler clamped in the vice, a hacksaw made a slot in the head of the other side, and my cordless impact screwdriver got it out.

Did wonder about fitting captive nuts to the wings as I have them here in the right size, and the fitting tool. But not sure how they would survive this very exposed place rust wise, even with SS bolts. (Nuts and bolts are fiddly to fit)

Also thought about using one of those plastic trim 'rivets' - the type with the popper down the middle, since the main support for the spoiler is a nut and bolt only a few inches away. The top fixing merely clamps the spoiler tight to the wing.

Re: Removing broken self tappers.

Posted: Sat Sep 11, 2021 5:37 am
by unstable load
It'd be a bugger to ever remove again, but Sikaflex will hold that nice and tight.