Fuel filter help

[Lucas87]

Hey up guys my berlingo had the dw8 straight d lump in it and someone has bypassed the factory fuel filter I've now replaced it with a brand new housing and filter etc but air is leaking back to the tank and the primer bulb doesn't go rock hard unless you take of thebinjector leak of pipe from the fuel filter housing lid and blank where it goes into the fillter then the plunger goes hard after a few pumps but the plunger itsself is wet with diesel any help would be fantastic it ran fine with the bodged bypass filter etc can't see any leaks anywear so I'm thinking maybe one of the leakoff pipes isn't sealing and it's letting air in when it was bypassed the leak off that fits to the filter housing lid was blanked off any help would be great thanks

[jj9]

It sounds like the leak off pipes are allowing air into the circuit, they do go brittle (hard) as they age and if they let any air in the fuel will drain back to the tank.

The diesel around the plunger could be because  of excess pressure when pumping the primer bulb because you have the leak off return blanked. In my experience the bulb never goes 100% solid, you can still feel the bulb squashing some, just with a higher resistance than on the 1st pump, if you follow what I mean.

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[Lucas87]

It sounds like the leak off pipes are allowing air into the circuit, they do go brittle (hard) as they age and if they let any air in the fuel will drain back to the tank.

The diesel around the plunger could be because  of excess pressure when pumping the primer bulb because you have the leak off return blanked. In my experience the bulb never goes 100% solid, you can still feel the bulb squashing some, just with a higher resistance than on the 1st pump, if you follow what I mean.

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Could I run it with the leak off pipe blocked like before or will it cause issues I got it running yesterday and was running fine but when you rev it it looks like loads of bubble in the pipe from the fillter to pump ?

[Lucas87]

It sounds like the leak off pipes are allowing air into the circuit, they do go brittle (hard) as they age and if they let any air in the fuel will drain back to the tank.

The diesel around the plunger could be because  of excess pressure when pumping the primer bulb because you have the leak off return blanked. In my experience the bulb never goes 100% solid, you can still feel the bulb squashing some, just with a higher resistance than on the 1st pump, if you follow what I mean.

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Could I run it with the leak off pipe blocked like before or will it cause issues I got it running yesterday and was running fine but when you rev it it looks like loads of bubble in the pipe from the fillter to pump ?

[jj9]

You could try it with the leak off pipes blocked like before and see what happens, if the problem goes away then you know what's causing it.

If replacing the leak off pipes use good quality pipe, stay away from that clear PVC braided stuff as that tends to go hard and leak, fuel safe silicone tube is a good choice.

It sometimes takes a while to get all of the trapped air out following a fuel filter change so a few bubbles in the pipe can be expected so it may take a day or so to settle down.

If there are loads of bubbles all of the time and the engine is surging / hunting there may be an air leak, possibly the gasket or the plunger. 

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