Thanks to various web page entries I’ve recently repaired a leaking fuel pump, and wanted to pass on my experiences...which maybe of use to other Golf owners.
I’ve got a very early Mk 4 Golf that has been very reliable. Very suddenly two weeks ago the cabin area of the car began smelling of fuel without any other noticable symptoms.
Following some advice on various web pages I did the following:
1. Disconnected the battery
2. Pulled up the rear passenger seat on the driver side to reveal a triangular shaped access panel below the rear seat.
3. Removed the three philips screws to remove a panel behind the drivers seat and got access to the top of the fuel tank and the fuel pump.
4. The top recessed section of the fuel pump sits inside what I’d liken to a large black plastic screw top lid (some people refer to it as a retaining ring) which has the centre section cut away showing the top of fuel pump. This recessed area was wet with fuel from a leak.
5. CAUTION re the next step – you may not want to try do this and just opt for changing the pump. I reconnected the battery and turned the ignition on which activated the fuel pump, this helped identify that fuel was seeping under pressure from the base of one of the protruding plastic pipes which forms part of the top of the fuel pump. There are two of them with fuel lines attached. I disconnected the battery following this check.
6. Advice on other web pages sensibly suggests draining fuel if there is more than a half a tank before doing anything else.
7. The two fuel lines are held on with an almost invisible spring clip within the end section of the fuel line. With a screw driver the clip can be gently pushed in which allows the fuel line to easily pull up and off of the top of the fuel pump. The lines can then be carefully pushed to one side.
8. Note the position of an arrow in the plastic moulded top of the fuel pump. In my case this was pointing directly backward to the rear of the car. It is a good idea to take photos to keep a record of the positioning.
9. Disconnect the power connector from the top of the pump by prising it out with a screw driver lift it vertically out of the top of the fuel pump and tuck it out of the way.
10. The black plastic retaining ring on the fuel pump has moulded sections around the diameter. With what I assume would be a proper VW tool engaging into these moulded parts of the ring, the ring can be undone. With a wooden mallet and as small piece of timber I was able to gently push against the moulded plastic and tap it repeatedly to begin to undo the ring. It undid in an anti clockwise direction.
11. When the ring is completely undone, the fuel pump and the rubber seal between it and the fuel tank can be very gently lifted out. The pump is a very tight fit and has to be angled toward the passenger side of the car to as it is lifted out to allow for the pump and the fuel gauge sender unit/plastic float attached to come out. As the fuel pump comes free if it is held over the open fuel tank this will allow for fuel inside the pump to drain out.
On closer inspection I found a hairline crack at the base of the fuel pump where one of the fuel lines attaches. When I looked closer I inadvertently snapped this off and found that the crack was over half way around this section and all the way through the plastic which was the cause of my leak.
At a local breakers yard I repeated this exercise to remove a replacement fuel pump from a breaking vehicle. I then got a bit hung up on the part number which was different to the part number on the pump fitted to me early Golf. It turns out the part had an ongoing revision process according to the local dealer who was helpful in tracing how the part numbers changed for early Mk 4 Golfs.
The VW dealer however wanted over £200 for the unit. Breakers yard - £35. I could have got one cheaper elsewhere on line but wanted to see the car the fuel pump came out of and also make sure it came out without any damage to the sender unit.
The fuel tank and sender unit are in two parts that connected together and are sprung loaded. This is worth bearing in mind when putting the pump back and having to push down on the unit.
Putting the new pump back was a little tricky. I tried putting the pump with its rubber seal back into position but could not get the seal to sit properly. In the end I did the following:
12. Removed the rubber seal from the pump, seating it into the neck of the fuel tank opening in its final position, wiping it with fuel as a lubricating liquid for when the pump was fitted inside it.
13. Orientated the pump correctly (in my case to show the arrow on the top of the new pump pointing to the rear of the car).
14. Angled the pump to one side as I lowered it into the tank to get the sender unit in and lowered the pump onto the seal and neck of the fuel tank.
15. Pushed gently down on the sprung loaded head of the pump to get the pump in its final position.
16. Placed the ring back on top of the pump and turned it clockwise to tighten it down.
17. Reconnected the fuel lines and power connection to the top of the pump.
18. Repositioned the cover back over the fuel pump/fuel tank.
During the first week of use I could still smell a very faint fuel smell. Although I had tightened the ring back down I did not go too mad to avoid what I thought was a risk of damaging it. But by pushing the down on the pump and tapping the retaining ring a little tighter with a mallet and blunt wood it solved the slight smell.
150 miles later it is still fine. Put half a tank of fuel in today to check out how the sender unit was working and all is OK.
On reflection this was very straight forward, and saved a fair bit on the repair bill. Hope this might help someone else...