Replacing the Fuel Lines

Modern Petrol now includes Ethanol which can eat away at old fuel lines from the inside out. I was unsure of the age of the lines in the van so decided to do a complete overhaul. A fuel leak in the engine bay could lead to a serious fire and not something I want to take any chances with.

Examples of perished fuel lines:

There are some excellent posts on the Club 80-90 Wiki I recommend reading around fuel lines in a VW T25:

• Fuel System – 1.9 Fuel Hoses
• Petrol Engines – Fire Warning

Once you’ve decided to changed your fuel lines, choosing the right size and quality hose can be a bit of a minefield. However, Brickwerks explain the different types and the 100% Ethanol rated hose they supply.

UPDATE: The 100% Ethanol rated Fuel feed pipe and Fuel return pipe kits from Brickwerks are recommended. 

(Although there have been no issues so far with the R9 kit used below, I’ll be upgrading to the 100% Ethanol ones when I do the job again, just to be on the safe side)

The kit fits as follows:

[Fuel Tank Outlet]
[7.3mm Hose][Fuel Filter][5.6mm Hose][Reinforcement Insert][Polyamide Pipe][Reinforcement Insert][5.6mm Hose]
[Fuel Pump]
[5.6mm Hose]
[Carburetor]
[5.6mm Hose][Reinforcement Insert][Polyamide Pipe][Reinforcement Insert][5.6mm Hose][Non-Return Valve][5.6mm Hose][8mm to 6mm Reducer][7.3mm Hose]
[Fuel Tank Inlet]

As well as the above, the kit includes grommets for the bulkhead and a variety of cable ties.

Tools needed for the job:

• Scissors
• Flathead screwdriver
• Petrol can (if draining tank)

Identifying the Fuel Lines

I have marked in red the hoses which will be replaced:

The lines then run through the bulkhead, under the chassis and connect to the fuel tank. Here are some additional photos to identify the fuel lines in the engine bay:

Fuel line from Fuel Tank Outlet into engine bay

Carburetor Outlet to Fuel Tank Inlet (via non-return valve)

Fuel line into the Fuel Pump Inlet

Fuel line between the Fuel Pump Outlet to Carburetor Inlet

Removal

First jack up the van and drain the fuel tank. This procedure is covered in my other post Replacing the Fuel Tank.

Once the fuel tank is empty the fuel lines connected to the tank can be cut, I snipped through the hard line with a pair of scissors. While under the van make a note of where the fuel lines go, you’ll need to channel the new ones in the same position.

On to the engine bay, unscrew the hose/jubilee clips and pull the fuel lines free of the Fuel Pump and Carburetor.

Do the same for the line from the fuel tank and finally disconnect the Fuel Pump to Carburetor. There may be some fuel left in the line but it is pretty minimal.

Fitting the new Fuel Lines

First I fitted the hose connecting Fuel Pump outlet to Carburetor inlet, I measured against the original hose and cut to size.

Next I fed the return hose hard line through the bulkhead and secured the 5.6mm hose onto the Carburetor outlet. (This section also includes a non-return valve to stop fuel going back into the Carb). Make sure the grommet is slipped over the hose before securing to the Carb, it protects the fuel line from rubbing.

Underneath the van on the Nearside I connected the pre-assembled 7.3mm/reducer/5.6mm hose section to the Fuel Tank inlet. The Polyamide hard line was fed from the the hole in the bulkhead down the same route the old fuel line had taken. I trimmed the hard line to the right length, inserted the reinforcement tube and pushed it into the 5.6mm hose before securing with a hose clip.

Finally I secured the whole return feed in place with the supplied cable ties.

Fuel Pump outlet to Carburetor inlet

Feeding the return feed through the bulkhead

Return feed secured in place with grommet

7.3mm/reducer/5.6mm connected to Fuel Tank inlet

Return Feed secured to chassis

Issue: The next step was to attach Fuel Feed line but I couldn’t get the 5.6mm hose onto the Fuel Pump. I took a measurement and found my Pierburg Fuel Pump has a 6mm outlet but a 8mm inlet. This meant it was impossible to fit the 5.6mm hose all the way on.

My solution was to get a short length of 7.3mm hose and a metal 8mm to 6mm reducer (had to be metal so it doesn’t melt in the engine bay).

The setup now looks like this:

[Fuel Tank Outlet]
[7.3mm Hose][Fuel Filter][5.6mm Hose][Reinforcement Insert][Polyamide Pipe][Reinforcement Insert][5.6mm Hose][8mm to 6mm Reducer *metal*][7.3mm Hose]
[Fuel Pump]
[5.6mm Hose]
[Carburetor]
[5.6mm Hose][Reinforcement Insert][Polyamide Pipe][Reinforcement Insert][5.6mm Hose][Non-Return Valve][5.6mm Hose][8mm to 6mm Reducer][7.3mm Hose]
[Fuel Tank Inlet]

Like the return feed I slid the hard line through the bulkhead with the grommet in place. Just after the engine bay the original fuel line went through a circular bracket, I fed the new line through this before it goes towards the Fuel Tank.

Just like the return feed, I cut the hard line to size, inserted the reinforcement tube and clamped in place. Job done!

Pre-assembled 5.6mm/Fuel Filter/7.3mm into Fuel Tank

Reinforcement Insert in Polyamide hard line

Fuel Filter and Feed Line secured in place

The last step was to put a small amount of fuel in the tank and start the engine. No leaks and it runs fantastic!

Conclusion

If you’re thinking of doing this with your van i’d definitely recommend spending the extra on the 100% Ethanol rated hose available from Brickwerks, the components are excellent quality and come part-assembled. Also, the Stainless Steel hose clips will last forever.

Make sure to check your fuel pump inlet size beforehand as you may need an additional length of 7.3mm hose and reducer.

It was a straightforward and quick job to do. (It has taken me longer to put this blog post together). The engine now starts first time and runs much smoother. Additionally, I feel much safer knowing the fuel lines are new and I can keep an eye on their condition.