Fiat Coupe Club UK

Undertray issues

Posted By: djmobi

Undertray issues - 12/06/2019 08:28

Hey everyone. We had some mental rain a few days ago and on the way home from work at 2am I was driving along a country road and despite just fitting brand new HID 5500k's which are amazing, i didn't see a load of flooding till too late and I hit it at about 40.

Now my undertray is hanging down and rubbing. It looks like it's torn out the clips and not damaged the undertray itself but I could do with a bit of advice on what to do.

I will obviously try and find some clips and order them, so if anyone has any advice on where to find them that would be cool, but I could also do with some advice on what I could use to secure it in the meantime.

I haven't had a chance to properly get under it yet so I thought I would ask to see if anyone has any top tips first.

Back at work tomorrow so I've got to sort it today
Posted By: DaveG

Re: Undertray issues - 12/06/2019 11:39

There's a load of screws at the front that screw into the bottom edge of the bumper, but they usually go rusty and break off / round off. There's a 13mm bolt at each side just ahead of the wheel that bolts into the bottom of the "eiffel tower" brackets which are close to the oil cooler (o/s) and intercooler (n/s) but often the bottom of the eiffel towers rust away too. There's a 10mm bolt that bolts into a short bracket coming from the radiator bottom support bracket (towards the n/s), and finally two more 13mm bolts (IIRC) at the rear that bolt into the subframe, either side of the sump, usually with big washers. But as well as the mounting points at the front/side rusting away, the rear points can become loose when the holes in the undertray grow bigger from wear, or the undertray starts to split/break at those points, meaning that any or all of the mounting points become fairly useless so that cable ties are commonly used to secure the undertray.

So in short, the answer is cable ties (or just remove the undertray for now, but that might take longer if you have to drill out any of the front screws)
Posted By: Possum

Re: Undertray issues - 12/06/2019 11:40

I would use cable ties as a short term fix as they are easy to fit and even easier to remove with a pair of side cutters.
Posted By: clanger

Re: Undertray issues - 12/06/2019 13:52

Longer term where you have a solid support, Rivet Nuts work well. I've done a couple round the front and one on an Eiffel tower where the original nut had torn out.
Posted By: djmobi

Re: Undertray issues - 12/06/2019 20:54

Cheers for the replies everyone. I had a proper look and the undertray is slightly damaged in a few places and has no attachments to the front bumper anymore.

I looked online and found what was described as undertray clips but by the sounds of it they won't be right if it's mainly bolts and screws.
Posted By: Master_Mariner

Re: Undertray issues - 13/06/2019 08:48

If you get some large washers, you should be able to re-attach everything nice and tight. Even over the ripped parts

If there is a bit of rattle with the under-tray where its ripped and vibrating against the bolts just extra tie that area down with tie cables.

Hopefully you won't have any problems moving forward.


Posted By: Possum

Re: Undertray issues - 13/06/2019 11:06

Originally Posted by Master_Mariner
If you get some large washers,

What us "old blokes" refer to as "Penny Washers", because of their size,
Posted By: Master_Mariner

Re: Undertray issues - 13/06/2019 11:43

Shhhh Possum...but your right. Very Old.

Posted By: MIB

Re: Undertray issues - 13/06/2019 13:25

The fixings that slide onto the front edge of the undertray are M6 Chimney Nuts.
I bought 20 on E-bay from adl-componentsltd, described as 'M6 Chimney Nuts Lug U-Nut Speed Threaded Fasteners Spire Captive Clips Fixings' for about 6 delivered.
Posted By: djmobi

Re: Undertray issues - 14/06/2019 07:47

Thanks for all the advice everyone. I have temporarily sorted it and have ordered some m6 chimney nuts to do it properly later
Posted By: Skiday

Re: Undertray issues - 25/06/2019 21:20

Isn't it illegal to fit after-market HID lights nowadays?
Posted By: barnacle

Re: Undertray issues - 26/06/2019 16:50

Yes. Also LED lights. I believe it's also part of the MOT check, too.
© 2019 Fiat Coupe Club UK