Disco 2 Replacing Td5 chassis fuel lines

Hello, noticed that there are some wet patches around the fuel lines on the chassis and thinking there might be a slight leak somewhere either hose itself or connection at the fpr. What is the best way to replace these? also, in terms of replacement parts, is it possible to make your own using normal fuel hose and connectors (what sizes would be required?)

I would be surprised if you can use normal hose and connectors. The Td5 fuel system is high pressure system. From the fuel pump it goes to the fuel filter at 0.75 bar, then back to the fuel pump and from there to the engine at 4 bar. You need to make sure any replacement can stand these pressures.

Graham Carter said:

I would be surprised if you can use normal hose and connectors. The Td5 fuel system is high pressure system. From the fuel pump it goes to the fuel filter at 0.75 bar, then back to the fuel pump and from there to the engine at 4 bar. You need to make sure any replacement can stand these pressures.

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actually, i think between between pump and fpor, pressure can go up to 7.5bar then it is regulated to 4bar after the fpr. From anther forum, someone made these observations using a custom made pressure sensor:

Raw fuel pump pressure (sender installed upstream of FPR):

- Runs between 6 and 7.5 bar (different vehicles)

- Not a steady value, even when idling oscillates in a 0.5 bar range

- Decreases as fuel heats up

- Decreases slightly as consumption rises (full boost)

Regulated fuel pressure (sender installed downstream of FPR and injectors, i.e. downstream of fuel cooler)

- Runs at 4 bar steady (nothing new)

- Decreases sharply when consumption rises (down to 3.5 bar)

- Can be used to diagnose FPR!! i.e. if not sufficciently steady or below 4 bar then FPR is toasted.

My comments came from the workshop manual. According to that, the FPR regulates by diverting excess fuel back to the tank. So I'd agree that the pump could have a higher maximum pressure. If the FPR is working properly, it shouldn't get above 4 bar.
But my comment about the pressure stands.
You can see a picture of the original parts here at the LR classic parts web site. https://parts.jaguarlandroverclassic.com/parts/index/part/id/L5.L5I.L5I02.L5I02050/brand/land-rover/

Graham Carter said:

My comments came from the workshop manual. According to that, the FPR regulates by diverting excess fuel back to the tank. So I'd agree that the pump could have a higher maximum pressure. If the FPR is working properly, it shouldn't get above 4 bar.
But my comment about the pressure stands.
You can see a picture of the original parts here at the LR classic parts web site. https://parts.jaguarlandroverclassic.com/parts/index/part/id/L5.L5I.L5I02.L5I02050/brand/land-rover/

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Thanks, was actually looking for the part number... holy f*** £406.76

Yep silly price for what is just 2 8mm pipes inside 10mm covers. I repaired a leak in the high pressure side by swapping the connections at the filter and the fpr so that the leak was on the low pressure side - and repaired that with an 8mm push fit connector.
That was 2 years ago...and still holding

I replaced the full set on my lads Defender td5. The pipes are fitted with connectors on the end that are not reusable, as they are heat shrunk onto the fittings. Which section of pipe are you looking at ? Are you sure its diesel thats leaking, as the brake pipes run the same route on the chassis.

A few years back on my old td5 disco I replaced the 2 rear lines with custom made braided hoses from a local hydraulic hose company.

don’t ask me the name of the company or sizes/fittings etc as ived been to bed since then but it cost me a fraction of OEM replacement pipes

I cable tied the new hoses to the originals along the chassis

tilly2 said:

I replaced the full set on my lads Defender td5. The pipes are fitted with connectors on the end that are not reusable, as they are heat shrunk onto the fittings. Which section of pipe are you looking at ? Are you sure its diesel thats leaking, as the brake pipes run the same route on the chassis.

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good to know. there was no odor but i assumed it was just because it was 'old' diesel