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wheel arch liner torx screws

BoxsterLL11

BoxsterLL11

PCGB Member
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I have just removed the front wheel arch liners again, the second time in two years which may have to become an annual event, to remove leaf debris etc that gets stuck behind them as well as removing lots of little stones that get trapped in the cooling fan shrouds and the suspension arms.
Am think of replacing the torx screws with stainless replacements.
Anyone done this and where to get them.
Only ones I could find so far are these.

https://www.accu.co.uk/en/sealing-raised-torx-wood-screws/377424-SHRKSW-4-5-20-20-A2
 
Torx screws listed are not a perfect replacement as they do not have they raised shoulder underneath the head that locates into the holes in the liners.
But apart from that they are a perfect size and am sure they will still keep the liners in place.
Not that my OE ones are particularly rusty but some are worse than others and if I need to pull the liners off every year I like the thought of stainless ones.
 
The shoulder prob stops them being overtightened and splitting the plastic. Mine are rusty too...maybe just replace them now and again.
 
I usually rub down, give a coat of cold galv spray and a coat of satin black. Screwing into a bit of wood holds them for spraying. Easily keeps them ok for a couple of years.
 
I started this thread over 5 years ago.
Was always going to replace the torx retaining screws for the wheel arch liners and undertrays but never quite got round to it.
Am currently giving the car its "12 year service" as due to recent back and hip problems all the service jobs are overdue.
So am going to town while the car is fully up an axle stands.
I removed the rear wheel arch liners the other day to improve access for the spark plug change (although not by much) and several of the torx screws were badly corroded. Two so badly that I had to grind of the heads with a Dremel which consequently melted the plastic liner which will also now need a repair.
I revisted the link I posted in #1 and decided these would not be suitable.
I did some more searching on Accu's website and found some that I thought might work so I ordered some.

In #4 it was suggested the screws can be just replaced, OE in mild steel again.
Design 911 sell the 16mm long ones at £1.08 each + vat and the 19mm long ones at £0.75 each + vat.
The corresponding speed nuts also at £1.08 each.

I am not a "keep original" guy if I can fit something better, cheaper.
So concours is out of the window !!!

So I bought something comparable screws from Accu with stainless washers.
Have tried a few in place and they seem to work fine.
Although some of my speed nuts are also in poor corroded condition and suspect these may be disintegrating when fitting the new screws in and therefore unable to tighten the new ones up.

Have found these speed nuts at another online retailer for half the price Design 911 sell them including vat.

I wil post up a few pics of the mod later.

And on the subject of the 12 year service, I am also replacing the gearbox plastic sump as part of the gearbox fluids change.
Its the "replacement" part as supplied by Design 911 at less than 50% cost of the Porsche part.
The plastic sump is supplied with OE aluminium screws to be tightened to 2.4 Nm.
Even my small torque wrench starts at 5Nm.

So once again, I am replacing these OE aluminium M6 screws with stainless ones.
A chap on youtube replaces his with carbon steel to a torque of 9Nm
I have been informed by Accu the max torque for the M6 stainless ones is 8.5Nm.

I also found the offside galvanised brace badly corroded so another job to sort.
 
Having started to de-rust, clean-up, treat and paint the corroded braces have realised they are not galvanised but just painted.
The front ends of these are just inside the rear tyres and at the mercy of everything the rear tyres throws up off the road.
So can't understand why these mild steel components have a basic paint coating when most other rear suspension components are aluminium.
Am using my tried-and-trusted system used on my MG's of treating rusty parts.
De-rust mechanically (rotary wire brushes/resin wheels etc) as much as physically possible, 2 treatments of Jenolite, 2 coats of brushed Bonda Rust primer (normally but skipping the 2nd as between burshed coats it requires 3 days to cure) and then giving 2 coats of sprayed etch primer instead.
Then any top coat to suit, in this case steel wheel silver.
 
Last edited:
Just to finish off this thread, having finished doing my 12 year/120k mile service and sorted the torx screws etc.
In most positions, the stainless torx screws I had bought did the trick in replacing the OE screws.
But in some positions, the speed nut clips were also so corroded that the new sharp threads of the stainless screws just caused the original rusty speed nut clips to disintegrate so I replaced them with new ones (I bought the new ones from the Heritage Parts Centre in Sussex).
In certain places, where it was either where the wheel arch liners overlapped and the upper one had the speed nut clip or where the fron valence screwed into the undertray and the undertray had the speed nut clip, there was too much flex between the two and the new screw threads would not start to screw into the spped nut. Perhaps longer ones might have worked.
So had to fit the originals in these positions.
So reading back posts #5 & 7 from 2019, I derusted the OE screws using a Dremel with a small copper wire wheel (at a much reduced speed otherwise the wheel just sheds all the copper wires !!!) for the underside of the head and thread, and my bench grinder wire wheel for the top of the heads as these were quite corroded.
Then as suggested, I screwed them into a piece of wood, 2 coats of etch primer and 3 coats of gloss black enamel (Tough Stuff enamel).
This worked really well.
Have posted a selection of pics if anyone is interested.P5080090.JPGP5080091.JPGP5080099.JPGP5100051.JPGP5110061.JPGP5140049.JPGP5150050.JPGP5170049.JPGP5200059.JPGP5220051.JPG
 
A word of advice if anyone else intends to remove the rear diagonal steel braces.
All the nuts/bolts keeping the braces, central bracket and cross-member in place all have a torque of 65Nm and are re-useable.
The bolts at the very front of the diagonal braces are single use bolts and are tightened to 30Nm + 90 degs.
I got this info from a Youtube mechanic who has a video to cover almost every job on a 981.
These bolts are M10 x 35mm high tensile steel, grade 10.9.
Genuine Porsche part number is 99907284001
I bought these as I was ordering other screws, washers etc from Accu.
 
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