Oh Nuts!!

[PaulMason]

Hi, wonder if anyone can help? When I got my 2008, W164 ML 320, it had neither of the 2 front undertrays. I've bought one from eBay which fits, but I am struggling to find some of the fasteners. The 3 deep recesses in the picture align to captive nuts in a cross member that runs behind the bumper, in front of the engine. Does anyone know what size/spec the bolts are as I have tried a number of options to no avail? The other fasteners aren't a problem as I have bought some clips and matching nuts, so I can make those work, but these 3 don't allow for a clip to be used so I need to find a nut that fits the captive.

Thanks in advance.

 

[SpikyMikey]

Does this help?
FG 164.125 - OIL PAN UNDERSHIELD > Mercedes EPC Online > nemigaparts.com
If this is the correct undertray. If not, try here:
FG 164.125 - ENGINE COMPARTMENT PANELLING > Mercedes EPC Online > nemigaparts.com

 

[PaulMason]

Does this help?
FG 164.125 - OIL PAN UNDERSHIELD > Mercedes EPC Online > nemigaparts.com
If this is the correct undertray. If not, try here:
FG 164.125 - ENGINE COMPARTMENT PANELLING > Mercedes EPC Online > nemigaparts.com

Thanks, I'll have a butchers and fingers crossed! Appreciated

 

[BTB 500]

I'd be very surprised if they weren't a standard metric size. You should be able to get the diameter from the hole/captive nuts that they go into, and an estimate of the length. I would probably add a washer plus spring washer to stop them vibrating out. eBay is great for stuff like this as you can buy small numbers of any size nut/bolt/washer/etc. you might need, and they're cheap enough to just try again if the size isn't quite right.

 

[W1ghty]

Pardon our interruption...

might be these???

 

[PaulMason]

Pardon our interruption...

might be these???

I've actually been there as it's just around the corner from my work and is mega handy as they do all sorts of fasteners and clips etc. Got some for the S Class and they are right but for the ML th ones I've got aren't right unfortunately. As an aside, would definitely recommend the seller and decent prices, decent quality and a really good range too

 

[PaulMason]

I'd be very surprised if they weren't a standard metric size. You should be able to get the diameter from the hole/captive nuts that they go into, and an estimate of the length. I would probably add a washer plus spring washer to stop them vibrating out. eBay is great for stuff like this as you can buy small numbers of any size nut/bolt/washer/etc. you might need, and they're cheap enough to just try again if the size isn't quite right.

I've tried an M4 (too small) but and M5 is too tight. Tbh the captive nuts are crusty and I don't want to force anything for fear of gacking them as I think the second undertray uses the same fasteners as the 2 trays overlap from what I can make out