Undertray fastener upgrade?

[jonnyspyder]

I have just removed and replaced my front bumper (2011 987 Spyder) and found a lot of corroded fasteners holding the bumper to the under tray or holding the wheel arch liners/brake air ducts in place, just wondering if anyone has found a better solution? The OE fasteners needing attention are the flanged black Torx head self tappers, two sizes: 4.8 x 16 with T25 head and 4.8 x 19 with T27 head (part numbers 999 073 22709 & 999 073 41801 resp). The shorter screws with the smaller Torx size heads are rather more feeble, they appear to be used where two panels are held together close to the bodywork but I think that the slightly longer screws will work without harming the body when in place... so has anyone found quality aftermarket screw of same dims, or has anyone swapped out with an alternate fastener that will work with the clips the tappers attach to - perhaps quick fit half turn Zeuss fasteners for example? I have scoured the usual aftermarket suppliers but either the flanges are too small or the correct size screw comes with the puny T25 head... any ideas/input appreciated

 

[AVI_8]

Not sure if this will help but I bought this kit to replace under tray and wheel stone guard fasteners for my BMW lately.
This is a problem on all cars, these fasteners just rust out after a few years, I often have to cut them off.

 

[AVI_8]

Would help if I posted a link!

170Pcs Galvanized Multicolor U Nut Fender Bumper Fastener Clips Tapping Screws | eBay

Mainly serves as a solid link between products. Product material: nut 65 manganese steel, screw stainless steel 304. Product attributes: multi-colored galvanized, strong rust resistance, the surface is not easy to oxidize and discolor.

www.ebay.co.uk

 

[jonnyspyder]

thanks - the cross head scares me, I think you are right about these fasteners being a problem on all cars but I fear had mine been cross heads many would have ended up needing cutting, at least with the Torx they all came out, and my car is my daily drive and is 13 years old. Perhaps I should replace with OE, if they last another 13 years

 

[AVI_8]

thanks - the cross head scares me, I think you are right about these fasteners being a problem on all cars but I fear had mine been cross heads many would have ended up needing cutting, at least with the Torx they all came out, and my car is my daily drive and is 13 years old. Perhaps I should replace with OE, if they last another 13 years

Yes fair point, though these and not torqued up tight and the screws are stainless steel and should not rust quickly, for peace of mind original might be best for you. They’re very easy to cut off though in the future using a reciprocating saw. That’s how I removed the original ones on my BMW and they were 8mm hex socket heads.

 

[½cwt]

Appreciate this is about 987, but on my 986 (all crosshead) I swapped all the 'self tapper' style screws to stainless steel. No more corrosion problems, other than the speed nuts rusting and breaking up, but you can't have it all. I also put a dab of grease on the thread and speed nut once it is screwed home.

 

[DRZ911]

Trying a bit of an experiment here.
Have got black torx self-tappers and loose washers in black stainless on order from ACCU.
Will let you know how they shape up against the single-part OEM version when they arrive.

 

[DRZ911]

Finally got my new stainless steel fasteners from ACCU fitted to replace the manky rusted steel ones (all of which are only 2 years old).




Cons :
Screw and washer are not one piece as OEM
No serrations on the underside of the washer as OEM
Pros :
Black finish A4 marine stainless screw/washer which will probably outlast the car itself
T25 Torx head same as OEM, but about 50% deeper so gives more engagement with the bit

Will let you know how these fare over time.

 

[911UK]

I have just removed and replaced my front bumper (2011 987 Spyder) and found a lot of corroded fasteners holding the bumper to the under tray or holding the wheel arch liners/brake air ducts in place, just wondering if anyone has found a better solution? The OE fasteners needing attention are the flanged black Torx head self tappers, two sizes: 4.8 x 16 with T25 head and 4.8 x 19 with T27 head (part numbers 999 073 22709 & 999 073 41801 resp). The shorter screws with the smaller Torx size heads are rather more feeble, they appear to be used where two panels are held together close to the bodywork but I think that the slightly longer screws will work without harming the body when in place... so has anyone found quality aftermarket screw of same dims, or has anyone swapped out with an alternate fastener that will work with the clips the tappers attach to - perhaps quick fit half turn Zeuss fasteners for example? I have scoured the usual aftermarket suppliers but either the flanges are too small or the correct size screw comes with the puny T25 head... any ideas/input appreciated

the basic issue is the only option are these basic oem fasteners

but as responses have shown there can be some alternatives

 

[stanuk964996]

Finally got my new stainless steel fasteners from ACCU fitted to replace the manky rusted steel ones (all of which are only 2 years old).

View attachment 97621
View attachment 97622

Cons :
Screw and washer are not one piece as OEM
No serrations on the underside of the washer as OEM
Pros :
Black finish A4 marine stainless screw/washer which will probably outlast the car itself
T25 Torx head same as OEM, but about 50% deeper so gives more engagement with the bit

Will let you know how these fare over time.

Could you link to the parts you used for this? Looking to do a similar job on my 997!

 

[flatstick]

Good post,
My car going in next week to be checked over ready for a June road trip,Did a trip in 22 and at 180mph heading down to Stuttgart the undertray came away, trust me it soon gets your attention!!!!
When we got back i went to my indy and he said the all do that with age, so now i have new fasteners and all the bits of the tray are laced together with zip ties so they all hold each other but can still be easy removed.

Dean

 

[DRZ911]

Could you link to the parts you used for this? Looking to do a similar job on my 997!

The company is ACCU.
https://www.accu.co.uk/?gad_source=...t8pbGblxm_1o7RftvCjcwdhA1pbPN9cRoC_2MQAvD_BwE
The part numbers that are shown in the previous photo are on the attachment below (equivalent to the original 4.8 x 16 with T25 head, Part No. 999 073 22709).
Hope that this helps.
Note :- this is NOT the equivalent for the fixing with the in-built spacer - 4.8 x 19 with T27 head, Part No. 999 073 41801.