Fuel leaking from tank

A couple of months ago I noticed there was fuel leaking from the tank of my C3. I took the car to my mechanic and we found that there was a hairline crack in the plastic fuel outlet of the pump. I purchased a new replacement pump (Valeo). We had major difficulty removing the locking ring securing the pump and in the end after sourcing a new plastic locking ring and O ring (original Citroen part) had to cut it to remove it.

The mechanic had a lot of difficulty re tightening the locking ring after the new pump was installed. It would appear to be tightening and properly threaded, but after a number of turns would come off its thread. After many goes it did stay in position, but fuel was leaking when the car was in motion. Eventually he welded a tool to get it secured more tightly, which appeared successful initially, but it is still leaking.

The mechanic tried positioning the O ring in a couple of different ways to get a tight seal, but I am still having the issue. He is competent and has looked after my car for many years. I watched the process. Just wondering if there are any insider tips about the O ring position or methods of tightening the locking ring to obtain a correct seal?

lumix93 wrote:The mechanic tried positioning the O ring in a couple of different ways to get a tight seal, but I am still having the issue

The o-ring sits on top the fuel tank before the fuel pump is fitted.

lumix93 wrote:The mechanic had a lot of difficulty re tightening the locking ring after the new pump was installed.

The locking ring rotates until the mark on the ring aligns with the arrow head on the fuel pump assembly.


The locking ring may be damaged now if it has been refitted incorrectly.


The Haynes Manual (here) Amazon link has some clear photographs of the procedure and is highly recommended for these sorts of jobs on the C3.

Thanks for the reply. I think that's the position we did have the O ring, but will verify about the positioning of the arrows and locking ring.

I will see if I can get my hands on a copy of the Haynes manual.

lumix93 wrote:I will see if I can get my hands on a copy of the Haynes manual.

You can have a discounted copy of the new C3 haynes manual, (including UK delivery) for less than £15 by clicking here - amazon

It covers the 2002 to 2009 models both petrol and diesel and has better paper quality than the older (2002-2006) manuals I have seen.