Plastic Nuts

[Faheem]

I was doing some work on the car over the weekend which involved removing the wheel arch liner, in order to remove it you have to undo two plastic 10mm nuts that secure the liner as well as the casing for the abs sensor.

I tried to remove this ever so gently but the threads just sheared off.

Any suggestions on how I can secure the liner and the casing back in place?

My goto would be to drill another set of holes close to where it sits originally and mount it there. However, my concern is I can't put a speed clip behind the hole that I drill to secure the screw in place. I could try a self tapping screw but will that even work with it being steel? Not really my area of expertise so any suggestions are appreciated.

Thanks.

Edit this is the nut that I was trying to undo when the threads sheared off.

 

[g8jka]

One of mine looks to have sheared off in the past before I owned it and they have just used a self tapping bolt in its place and it holds fine so you will be ok with one of them. The 2 plastic bolts underneath the car that hold the rear of the liners are also prone to the threads shearing off.

The one used on mine looks like this

 

[Faheem]

@g8jka is it still mounted in the same place? Unsure whether it is possible to drill out the old one or just use a self tapping screw in another location.

 

[mrscalex]

Fraid you didn't read my engine removal thread that told you how to remove these safely

I did snap some last time all the same when I removed the wiring centre heat shield.

I drilled out the stub of the thread. Put a self tapper through from the wheel arch in a slightly enlarged hole and secured it with a starloc. That way you get a tiny bit of wriggle room to aim it where you need it as it can be crowded down there. I then used a new plastic lock nut of the original size on the correctly sized self tapper. From the engine bay it all looks original. If I find the size self tapper I used I'll post.

 

[g8jka]

@g8jka is it still mounted in the same place? Unsure whether it is possible to drill out the old one or just use a self tapping screw in another location.

I can't remember exactly but I have a feeling it is either just above or below or either side of the original which has been removed. The unit is still located in the same place.

 

[Faheem]

Thanks.

I devised a temporary solution. Whilst it isn't perfect it will do the job just fine for now.

There were enough threads left on the bottom that I was able to put a nut there. I then cut the head of a bolt off and tightened that into the nut. The rest you can see.

For the top, however, I had no choice but to bolt the casing into the liner. Not perfect but the liner is secured so should hold the casing.

 

[Faheem]

@mrscalex Rob, I'm curious to know what the correct method is  do you have a link to the thread.

I did read it when you first posted but I skimmed through it could have saved me hours today had I read it carefully

 

[mrscalex]

I'm on my mobile so can't scan through right now. I hope it put it in there after saying that!

There's no reliable way I can figure out other than using a dremmel to slice through the plastic nut. There's no guarantee with releasing fluid and it's a very brittle projection.

 

[DrWong]

I'm on my mobile so can't scan through right now. I hope it put it in there after saying that!

There's no reliable way I can figure out other than using a dremmel to slice through the plastic nut. There's no guarantee with releasing fluid and it's a very brittle projection.

Thanks for this! I'm sorting my sills and snapped the upper studs holding the front arch liners on both sides. I needed to remove the plastic trims at the rear of the sills so searched the forum and saw your tip. Got a cheap rotary tool from Amazon and used cutting discs to first cut the base of the plastic nuts off. I then pared back the plastic until I could just about see metal and then used a sharp knife to cut the final bits of plastic away from the thread. Took about an hour each and I cut into the plastic trim pieces a bit, but infinitely preferable to snapping a metal stud

 

[Mazza]

I managed to snap one off a while ago. These studs are welded so ground down the bit of remaining stud, centre popped it and drilled a hole through. Then used a hex head self tapper after treating the hole and surround with anti rust paint.

 

[DrWong]

Yeah, I think I’ll have to do similar for the ABS ones I did in. Did you drill through into the engine bay then? If so, presumably you treated both sides of the metal?

 

[Mazza]

Yeah, I think I’ll have to do similar for the ABS ones I did in. Did you drill through into the engine bay then? If so, presumably you treated both sides of the metal?

The one I snapped was the underneath, into a box section, so could only get one side. Definitely paint both sides if you can get to both.

 

[DrWong]

My underneath ones came off fine on both sides, which was lucky as I wasn’t even considering they might snap - despite having already snapped the ABS ones! It was when I realised I needed to remove the rear plastic trims that I didn’t want to take any chances and searched the forum

 

[Nodzed]

Same as, drilled out and self tapper.

 

[DrWong]

My plan is to drill hole, insert stainless self-tappper through from engine side, trim off the sharp tip in the wheel arch, treat / paint both sides, then replace plastic nut

 

[the Nefyn cat]

Or if you feel like spending a bit more https://en.wikipedia.org/wiki/Rivet_nut .Useful things once you've got the magic setting tool.

 

[Sean d]

Or if you feel like spending a bit more https://en.wikipedia.org/wiki/Rivet_nut .Useful things once you've got the magic setting tool.

I use riv nuts at work and have used them on the Z, I sheard both bolts on the passenger side mirror when I stripped the 2.8