406oc.co.uk

Hi All i am after some advice on how to replace the fuel filter on my 406 HDI, it may sound silly but how do you open the filter up so that you can put the new element in. The filter housing top is black with an arrow pointing one way with a negative sign and an arrow pointing the other way with a positive sign and a plastic shaped nut in the middle, i have tried to remove it in both directions with quite some force and no joy, so am after any tips on how to remove the top, many thanks in advance.

Had the same problem hith my previous Hdi90 cistern, never resolved it

If you look here I think this is the answer

Oh and welcome

Many thanks for the reply will try what is suggested in the thread and remove the canister and stick it in a vice. Will report back on my findings

Have you tried putting a 22mm (I think) socket and extension bar and twisting it anti-clockwise? It will be quite tight as a little bit of dirt does get under the lid and tends to put grit and debris on the rubber o-rin and the threads and of lid to stop it from twisting off.


Luckily mine came off by hand but once I replaced the o-ring it would turn a little bit and then stop and I faffed thinking it was going on crossed threaded but in the end I sussed it just need some force to twist in and lock in. (I spent about 45 minutes studying the entire assembly lol.

I did read that some do crack the housing though.

Maybe be worth while buying a new housing and lid to pop the new fuel filter in and replace the rubber o-ring?

Is it Bosch or Siemens fuel system? Bosh has 2 hoses on the top, Siemens hase 3.

The one that needs to go in a vice (not always) is the one that has a plastic ring nut around the top of the filter housing, the reason for this is that you can break off a pipe if you slip off the plactic ring nut whilst trying to undo the ring nut.I've done several dozen of these filter changes and broken two.

The one with the plastic nut is best left on the engine, it is easier to undo the housing top because it is solid on the engine and is less likely to get cracked than if it is in a vice.
Simply turn the nut 90 degrees anti-clockwise to undo it. it might be tight as there is a spring clip under the housing lid,(plus the reasons that bruce gave) use a socket, extension and a ratchet.

Don't worry about dirt because you can clean the whole housing with brake cleaner or carb cleaner before assembly.

Not all 90 HDi are self priming, my 406 90 had a hand pump, but the 110 usually are.

Its strange that i dont usually have much luck but i have done 5 fuel filter changes on my picasso hdi and 2 on my 406 hdi and never had any problems with unscrewing the filter housing and have never had to remove one from my car. I always disconnect the 3 pipes and i use a strap wrench and always got it 1st go without any cracked filter housing (yet)...just dont go wild and if you can get a strap wrench use it as i have always found it very easy with one, dont use a chain wrench as a mate of mine did ...DOH !!!

welshviking wrote:Its strange that i dont usually have much luck but i have done 5 fuel filter changes on my picasso hdi and 2 on my 406 hdi and never had any problems with unscrewing the filter housing and have never had to remove one from my car. I always disconnect the 3 pipes and i use a strap wrench and always got it 1st go without any cracked filter housing (yet)...just dont go wild and if you can get a strap wrench use it as i have always found it very easy with one, dont use a chain wrench as a mate of mine did ...DOH !!!

Some you win....and some you lose

i used a chain wrench when I did mine, it's all I had to hand Didn't damage it tho, I couldn't turn it by hand but with the chain wrench it was a piece of gateaux. I've bought a strap wrench for next time anyway.

Thanks for the replies guys, mine has 2 pipes on the top, i am going to have a go at it at the weekend and fingers crossed wont break anything as a new one is £80+ according to the local dealers

You'll be fine, your type is usually one that comes apart without too much fuss.

A couple of things to note....take note of how everything fits when you remove the top and when you refit the top make sure the lid goes down square, it can be a bit tricky to get it square (it will leak badly if it isn't square).