IMPORTANT MOD: Bulkhead Drain Plug

[Nige_RS4]

My local specialist reminded me that the next time my car goes in, it needs the bulkhead drain plug removing.

They are seeing an increasing number of A4s (B5 chassis) with electrical failures (and mouldy carpets) due to this plug becoming blocked and water leaking into the passenger footwell via the pollen filter.

Essentially, it is there to prevent water getting in to the bulkhead from below, but this is very unlikely, and as out cars get older, the chances of this drain plug becoming blocked increases.

If you're under the car it's a 5 second job to prise out. If not, you need to lift the battery up and remove it from above - it's an odd shaped rubber bung thingy!

From memory, I have heard of wet passenger footwells in this forum before - maybe this is the cause??

p.s. mods might want to make this a sticky?

[ZeroK66]

Good point, been meaning to check mine. Going to have my battery upgraded, so will do this at the same time.

[shineydave]

there's actually 2 in there, one under the battery and one under the servo, i mentioned them in my write up on servicing the S4. i'd also recommend removing the drip tray above the pollen filter as there's a drain at the end in there that was also blocked on 2 S4's i've seen recently.