Td5 fuel filter.

When you say "at the front of the filter" do you mean at the actual filter(behind driver rear wheel)? The filter screws on to a filter head. Filter head has 4 connections(thus 4 hard lines coming to/from it). Do you have a leak at the filter head?
better to take photo.

What 'usually' happens is that when you remove the filter to replace it, there is a rubber o-ring that doesn't always come off with the old filter, but there is a rubber o-ring on the new filter that when you fit it, you inadvertently now have 2x rubber o-rings, and it can leak from there. If this is not your issue, then they can leak from the line fittings in one of two ways.
The head has 4x screw in ports where brass fittings attach. One leak possibility is that the filter head has a crack at one of those threaded ports. The lines themselves have quick fit(or push fit) type connections that that push into the brass fittings coming out of the filter head. The push fittings have two tabs(square shaped) that need to be squeezed for the quick connect to release ... kind of like the trans cooler lines at the trans cooler. When new, you can use your fingers quite easily to squeeze the release blocks, but when a bit aged, you need a tool of some kind. 'pliers' specially designed to make it easier to squeeze the quick connects exist(and relatively cheap), but if you have patience and tools to make your own this is also an option.
You need to clean up this area so you can see if there is a leak at the threads of the brass fitting(can be bought if needed) or at the quick connection fitting. The brass port is generally not a problem, the filter head can crack or the o-rings inside the quick connections can get leaky.

But if you mean that the leak is way up front near the fuel cooler or fuel block(or fuel pressure regulator), then again all fule lines are quick connects, basically same connectors all round. They can be had aftermarket if the quick connect have leaky o-rings.

Bit of apology, I didn't see that one of you pics can be read more easily. I think you have one of the pics 'arrowed'. If this is where the leak is, then again, clean up and take photo of it leaking.
Like I said, if it turns out to be the quick connect, you can undo the brass port off the filter head and size up the exact size quick connect.
I replace some and added some to my TD5, and just got a whole bunch of ebay for reasonable money. IIRC(and not 100% sure of this) .. the size is something like 7.89mm or roughly that.

Ebay example.

You can get them from some car parts places. VPW has some for not a huge price.

The strange 7.89mm size is because technically they are 5/16"(i.e. 7.89mm!)
If you have a heat gun(180° deflector is handy too) you heat up the hard line and remove old, and replace with new. it's not easy, but not impossible.

But you need to be sure it's not the filter head thats got a micro-fracture at the threaded port. Old one on TD5 had this, and I removed the brass fitting, used thread seal and got it sealed up for a bit while waiting for a filter head to come up to replace it.

Thanks Arthur, the leak seems to be where the line joins to the quick connect fitting.

Educated guess, it the low pressure return line, outboard front of the filter housing, that's a short line back to the pump, that's been disturbed when changing the pump.
I'll order a handful of the fittings.

Quote:

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Originally Posted by V8Ian

The plumbing seems strangely complex, to me, two laps of the car before it's used. [bighmmm]

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Not really, The low pressure feed goes into the filter, gets filtered and then returns to feed the high pressure pump. The high pressure feed goes to the injectors, the unused fuel returns via the fuel pressure regulator to the top of the fuel filter housing where it then goes in the air bleed return line to the fuel tank. I am guessing that there is a provision for air in the filter assembly to return to the tank and the line from the FPR makes use of that.

The quick connect fittings finally arrived, they feel cheap and flimsy.

Attachment 193057

These fittings do not resemble what's in the car. The ones on the car appear to have a knurled collar, are they supposed to unscrew? Where the fuel line enters the fitting, there is an O ring, this is where the leak is. Can the O ring be replaced? Is the fitting on the car Land Rover/ D2 specific and available?

I think those types still fit the button press style, which is what should be on the D2. I don't know if they changed the D2 vs the D2a in any way .. can't think why they would tho.
The connector type is the one I linked too on Ebay about 4 posts prior. Thats what they should look like. if you view that, the white square is a release button. one on each opposite side. And the tool to help remove the recalcitrant connectors looks like needle nose pliers with the tips curled into each other, like pincers.

The style you have there is the fitting on the top of the fuel tank for pump body.

As the connectors age, they get harder to press the buttons to release the quick connect.
A bit of WD/CRC/whatever can help, but when new they are easily pressed by fingers to remove them.

The type you have, still get hard to remove with age, but I found much easier than the button type that should be at the fuel filter and up at the FPR. There is one collar type fitting up at the FPR too(like the auto trans cooler type collar fitting).

And yes, o-ring inside the quick connector, but hard to remove and refit(in my experience). I haven't seen o-rigns for sale for them tho, I tried to use a regular small o-ring, but stuffed the connector trying to get the old one out.

Ok, had another squiz, armed with your information, Arthur.
I have the wrong fittings, I need a 90⁰ elbow. A closer look and decent torch revealed the buttons that need squeezing. They look like the same fittings that Incisor and I struggled with on the L322. We couldn't buy the right tool and I forget how wa eventually got them undone, but I'm pretty sure it involved some words that wouldn't be used in polite company.
The L322 had better access than the Disco.

Before any other smart arse says it, it was a good only the impolite Inc and myself were present. [tonguewink]

Ordered the last two 90⁰s in stock, from some Victorian show. They're the same style as original.

Quote:

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Originally Posted by V8Ian

....They look like the same fittings that Incisor and I struggled with on the L322. We couldn't buy the right tool and I forget how wa eventually got them undone, but I'm pretty sure it involved some words that wouldn't be used in polite company.
The L322 had better access than the Disco.

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Pair of pliers or vice grips and a small something between the tool and the buttons.
First time I came across it, I obviously didnt' have tool. I used a pair of pliers and taped a small nut to the ends of them(on the inside). Still didnt' have enough hand power to squeeze them, and I think the pliers were crap anyhow, but also used vise grips over the pliers with two small nuts taped to it.
Back then I used to live within 1 minute of two car parts places, and I think I found the correct plier tool at Bursons.

Obviously you have removed the wheel for better access too [bigwhistle]