Jump to content

Draining out fuse boxes


Recommended Posts

I had an "interesting experience" yesterday crossing a stream (twice) - somewhat deeper than expected after v heavy rain for the last 2 days and a normally 8" deep stream on the farm started coming up over the bonnet! Twice because I then had to go back through it as there was no other way to get home.

When I was drying out the inside later on I discovered that the compartment under the drivers seat ain't watertight. Now this being a Tdi, there's no ECU to worry about, but the late Tdi 90s still have the "engine compartment fuse box" under there, same as a Td5, plus the heater plug timer and a bit of wiring. There was about 1/2" of water in there after four bonnet-depth water crossings.

I could just drill a hole and put a blanking grommet in that I could take out if it needs to be drained, but I wondered what other solutions there might be... ?

So ... what would be ideal is some sort of one-way valve which will let water out, but not in, in other words if there is water in the compartment it will drain out through the valve but if the vehicle is in deep water it won't come in.

I seem to recall that some old vehicles (series 3s??) had some sort of one way valve on the axle, to act as a breather but not let water in, would that work? or if not, any other ideas please?

Oh and any recommendations for waterproof spotlights would also be welcome as the Ring ones on there leak a bit under 18" of water :blink::lol:

Happy New Year :)


Link to comment
Share on other sites

Series vehicles do have breather valves, but I don't think they'll work unless they are upright. Air filters casings have a thing you could use on them that would do the job. Funny rubber things that sticks down underneath.

Don't know the proper name, but no doubt Ralph will be here as quick as a greased whippet up a drain pipe to give you part number etc.


Les. :)

Link to comment
Share on other sites


What about an auto-bail for a boat?

There are some which have a venturi arrangement and actually suck water out when you are moving through water, but there also ones with a float valve which shuts off when it is in water but allows drainage when the boat is out of the water.

Wouldn't be terribly hard to make - if you've got a lathe, some plastic & an O ring for the seal.

You could even just put a plug-hole from a sink in it? - or a hole & a cork!


Link to comment
Share on other sites

Guest diesel_jim

That rubber bit is called "Valve assembly, air intake", park # NRC8955, used on all air bozes from 2.5 NA up to 300Tdi.

personally though, from experiences with them on my air box, i'd not bother Steve, i'd put the rubber grommets in the seat box and then blitz it with mastic at every leak-looking place.

Link to comment
Share on other sites


Hadn't thought of using the 'fanny' off an air filter. When my Safari snorkel arrives I'll have one going spare, as I'll be replacing it with a WD40 cap for waterproofing.

The only trouble is they aren't all that water proof in terms of letting water in the wrong way - but it might be OK. I'll do some "testing" - cheers for the idea :)

The box has already been blitzed with silicone - which is annoying me because I can't see where the water got in, it should be watertight for a quick immersion like that (about 15 sec crossing the stream and about 30 crossing the main river) even if water would get in if submerged for a long time. I had to drill a hole in one corner and park it on a slope to drain the water out!

Also, there is nothing like water coming over the bonnet to act as a sharp reminder that the previous owner never bothered to properly seal up the snorkel he fitted! :blink:

Si - I'll also look into the auto-bail idea, thanks :)

Link to comment
Share on other sites


sealed his there are pics on his website.

with a full explanation there to.

Trouble is that you can "think" you have it properly sealed - I already did :blink:

I wasn't in the water for long enough to have the water entering from inside (only about 1/2" got in the footwells with the doors "closed" - LR door seals being what they are :lol: ), and I don't do that much deep wading, if there is a foot of water inside the vehicle I am going to have bigger problems anyway so draining the fuse box isn't going to be top of the list, I just want to stop it getting in from underneath during a quick submersion which on the face of it should be simple ... but :angry:

Got a couple of good photos on the second run back through though, not as good as yours of Wales but still fairly respectable - wish there had been somebody on the outside with a camera too but I was by myself

Link to comment
Share on other sites

As Tony says - seal it. Before you do, coat everything inside with WD40 or vaseline. Electricity + copper + water = green fluff and dead vehicle very very quickly. I don't know what the box looks like, but if you could squeeze a dessicant pack in there too it'd catch any moisture that seeps in.

I suppose another method would be to pressurize the box using a feed from a compressor if you have one.

Link to comment
Share on other sites

Dunno, if the earth moved I didn't notice - too busy away in the 90 shooting stuff for the freezer - fresh gosling legs and new potatoes straight from Dad's garden for supper, yum :)

Off fishing this afternoon as it is an absolutely glorious sunny day here. Is it still snowing? :P

Photos from Christmas will be posted when I get home, catching the ferry back tomorrow morning at 0600 and an hours drive to get there which means getting up at stupid o'clock :blink:

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...

Important Information

We use cookies to ensure you get the best experience. By using our website you agree to our Cookie Policy