Fixings for wooden panel - what are they?

[HPsauce]

Taking out the wet "wooden" panel under the passengers feet to tackle my "blocked drains" I realised that the number of screws holding it in place was precisely zero.

From the evidence of odd bits of cable there and elsewhere the car has obviously at some time had a mobile phone car kit installed and I guess they needed to access the relay panel and just binned the fixings and threw it back covered in carpet.

Can anyone tell me what the correct screws/bolts are to hold it down correctly? Once it's all dried out I hope to fix it back properly, I'll also probably paint the board with marine varnish or similar to protect it better against future mishaps!

[Adrian E]

They are a slightly oddball screw size - TPS or local dealer can get them and they're not horrific cost. I need a new board for mine as one corner has swelled at some point. The boards are extremely expensive - am tempted to make one from marine ply I've got from making a table extension!

[Goran]

I have a better suggestion. Why not make a new one out of a nice piece of perspex?
That way you will also be able to line it up with the holes properly.
Only one question - why did Audi use chipboard? To absorb moisture/condensation?
Maybe use a piece of perspex with some felt glued to the back?

[Dezzy]

It's MDF and i can't think of any other reason than it's cheap and easy to cut, although when they get wet don't they swell? The screws go into plastic and therefore will probably have been Flange Head Pozi Drive Self Tapping Screws (i don't have any either) and i'd expect then to have been black. Not sure about size.

I was thinking along the same as Adrian, Marine Ply and using the compressed cardboard one as a template.

[HPsauce]

Originally Posted by Adrian E

a slightly oddball screw size

I tried googling that and got some very strange images!
I haven't looked closely, but are they bolts into a metal fixing then? If so I'll try a random selection from my collection until I find something that fits.

Ah, missed this first time round.

Originally Posted by Dezzy

The screws go into plastic

I'll have a careful look when the weather improves.

[HPsauce]

OK, I had a look just now and it looks like any reasonable pointed screw of the right length will do the job, as long as the head is large and flat enough.
I have plenty in my stock to solve this, but found another problem....

I offered up the board (still drying and rather swollen along one edge) to realise the holes were nowhere near aligned.
After a bit of mental 3D gymnastics I worked out which face was out (brown) and which faced the relay panel (black foam) and which edge was the bottom (2 screwholes very close to it).
Whoever had been in there before had put the thing up upside down! No wonder there were no screws; nowhere for them to go into.

The only bonus on this is that the water damage and swelling is now on the top edge so 3 of the 4 screwholes are bone dry and as-new, with the third only slightly swollen.
Though if installed correctly the panel is actually about 1cm clear of both the floor and transmission tunnel side, so any water ingress would have to be quite severe to affect it much.

Anyway this highlighted another query. At the top of the panel is a flap of heavy, black insulation material, sort of bitumen-coated. The previous installer had placed the panel on top of this which I suspect is wrong.
Looking at it I think the panel should be a snug fit over the whole face of the relay panel, with that flap laid over the top edge of the panel, but then under the carpet (if it reaches that far).

Could someone have a quick look in their front passenger footwell beneath the very top part of the carpet, to confirm that please?

[Adrian E]

From memory the only way you can get the panel to fit properly is to put the flap over the board, otherwise it holds the board away from the relay panel

I can pull a screw from my panel and measure the shank and head sizes, plus thread length if you want? Car will be coming out tomorrow for the 1st time in a fortnight!

[HPsauce]

Originally Posted by Adrian E

fit properly

It will finally, when I'm finished.

Thanks Adrian, you've confirmed what I thought. It wasn't like that before so there was water around the relays - bloody car phone installers!

No need to measure the screws, I've got loads of varying sizes so won't have any problems getting 3+1 to fit. Looks like 20 to 25mm is about the right length depending on the amount of swelling.

[HPsauce]

Originally Posted by Dezzy

It's MDF and i can't think of any other reason than it's cheap and easy to cut

I think there may be another reason, sound and electrical qualities.
With everything out and the relays exposed you really can hear them clicking away.
MDF is pretty sound-deadening whereas a harder material such as ply or Perspex would actually transmit it. And Perspex might create static.
OK, there's a very thick foam-backed carpet on top as well as an overmat, so maybe not a problem?

[Dezzy]

Oak or Mahogany 20mm thk is a good soound insulator

And yes, i've been driving around for a while without mine in and it's noisy, a lot of road noise without the carpets fitted too.

The flap you talk of must be a FL thing as i don't have that.