brake bleed screws: sizing them up.
 

Can anyone tell me the thread spec for the brake bleed screws, and the true size across the flats. I want to get some spares before giving mine some grief, as some beggar has pretty much rounded them all already.

I asked the jokers at the local Porche parts place, they were unsure of any sizes, and wanted over £9 ($15 ) for the front ones alone, but I think they will be standard metric sizes.

Mines a N/A 944 2.7L 1989, and I think the front bleed screws may be different to the back (I'm guessing 8 x 1.25mm front and 7 x 1mm back). Anyone know for sure?

On my car across the flats in back is 7mm

The front is not 8mm, 7mm or 5/16 - I'm still trying to figure out what it is. I'm going to try a 9/32 this weekend.

If it's not any of these then I'd guess 7.5mm but I'm having an awful time trying to find a 7.5mm deep socket or 7.5 mm wrench