Engine undertray fixings

[mr.oogieboogie]

Dos any one know the size of the rear engine under tray fixings as the holes near the rear wheel arches look larger than the others for the under tray.

All the best

[DaKa]

I had a similar problem, I believe caused by the previous owner breaking the original fixings.

I used brass thread rubber expanding rivnuts which have been in place for a couple of years without issue.

https://www.ebay.co.uk/itm/282732204333

Can't recall if M6 or M8

[fjmuurling]

On my SE M6 x 20

[sailorbob]

You may find a mix of sizes, mine is like this where the some of the originals were replaced with larger rivet nuts. They were falling out and the holes had ovalled so the holes needed drilling out and larger ones fitting.

Is a loose undertray the cause of your noise?

[tomcattom]

I had exactly the same on mine @sailorbob. My undertray was held on with self tapping screws when I got the car Most of the rivnuts were either completely missing or the bolts in them had snapped off and were spinning in the body. I ground all the old rivnuts out and replaced most of them with standard M6 rivnuts but a handful had to go up a size to M8 because the hole in the body had to be enlarged for one reason or another.

[MrDangerUS]

I have replaced all of them with screw-in M6 x 15mm Furniture Hex Drive Flat Head Nuts For Wood with epoxy.

Now, I can use an electric ratchet to drive the screws in; no over-torquing concerns.

I'd love to include a picture, but the ridiculously low picture size restriction of this site makes it impossible.

[Sparky]

A quick edit - even on a mobile - makes it perfectly possible.  What would be the benefit of a 5+Mb pic of a fixing?

[snowrx]

I've done the same on my car. I cleaned the holes out well, then put some epoxy on the outside of the insert and gently screwed it in, and wiped off the excess and allowed it to set well.  I put a little anti-seize compound on the inner threads to help with disassembly.  I just hope the metal used doesn't corrode too quickly! Maybe there are stainless ones available.