Air in fuel line

I'm getting air in my fuel line somehow. You can see the air bubbles in the inline fuel filter.
I have just replaced the petrol fuel tank and used an air line to clear the pipes.
This problem also occured before I changed the tank and I have checked all connections are tight.
Anyone had a similar problem or know a methodical cure.
Thanks in advance

air can be drawn in from a few places. firstly remove the fuel sender unit from the tank and check the tube that goes in to the fuel, before replacing make up a fuel pipe that will reach from your lift pump to the tank with no joins in it, prime the pipe up using the hand primer and see if you still have air in the system, if you have still got air getting in the chances are the fuel pump as an air line crack on the union where you thread the pipe in on the pump. other than that if you have a new fuel line it could have a pin hole in it, air can only be drawn in from the lift pump back to the tank.

I don't know what Landy you have, but if your pump has the glass sediment bowl on it, why are you using a in line filter? take it off, you don't need it, its just one more thing to go wrong in my opinion

Dopey said:

I don't know what Landy you have, but if your pump has the glass sediment bowl on it, why are you using a in line filter? take it off, you don't need it, its just one more thing to go wrong in my opinion

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Dont know about landies but the trucks always had air in the glass bowls its normal, you could pump all day and it would still be there.

Same for the in line filter if you fit one, always looks like its almost empty

I dont think you should have air in the glass bowl, check that the seal around the top of the glass bowl is sealing correctly. Remove the bowl and check the seal that mates it to under the fuel pump. If that seal is damaged or not seated properly the pump will suck air in from that gap. Hope that helps. My first Post

Thanks for your replies chaps.
Its a series 3 109 petrol.
There are no air bubbles in the glass bowl but in the inline filter.
The inline filter did get dirty so it was doing the job its meant to do though I have changed the fuel tank now as it was rusted and had a slight leak.
Have checked the seal above the glass bowl and all seems ok.
The problem does not effect normal running but as soon as I do a spot of greenlaning and bounce the landy around I have running problem as if it is being starved of fuel. The engine struggles with a lack of power and depressing the accel. does absolutely nothing. New Zenith carb has been recently fitted.

My inline filter always has air in it, normally only about a quarter fill. You could pull the fuel line out of the carb and pump the fuel pump manually, would be a guess from there, but you could make a guess to wether or not there is another fuel being pumped. Sounds like you are saying that it runs fine on normal tarmac, so you dont have any problem with "power" when you floor the accel in normal conditions? With a new fuel tank and you are sure that there are no blocked pipes in the fuel line and you are getting enough fuel at the inlet to the carb. saying you have a new zenith carb installed , maybe check the float level in the carb. If it always the case when driving on bumpy terrain might be the carb, or if its intermittent, check everything is tight in distributor. I had a similar problem with my condenser being slightly loose.

Hi I have the exact same issue. I just changed my tank and now I get 400metres down road and the car starts bouncing and jumping.

Inline filter shows are bubbles popping out into fuel mix when this happens. If I then manually prime the pump lots I can set off again. Then 500 metres down road same thing happens and loads of air again!

How did you fix it as I could do with some help. Wondered if it is my pump diaphragm but seems doubtful as all was fine before I changed the tank...

Sounds like the tank pickup pipe is perforated sucking air when fuel sloshing around . Does it do it with a full tank?

Common problem with old petrol pick up pipes.

Had a problem with the diesel the other weekend. Idling nicely in the yard to warm up then as soon as I got out of the gate it instantly died. Primed it on the lift pump and eventually fired up and idled nicely again. Set off and died again, 20 mins to do 50 yards.
Got it towed back to the yard and when primed it pushed out a load of air from the filter pipe when cracked, so decided to change the lift pump back to the original one still knocking about in the shed, changed all the pipes from pump to filter and still air.
Then changed the pipe to fuel tank and decided to see how the brass lift pipe looked, when removed could instantly see the problem...... no soddin fuel in the tank
Turns out the new sender I put in was giving false readings and there was me thinking I was getting good MPG..................
I'm sure theres a moral there somewhere but I don't want to hear it

Hi thanks I'll check the pickup pipe tonight. Plenty fuel in tank so shouldn't be the sender...

Does anyone know where to get a new petrol pickup pipe or the part number? I can only find diesel online?!

You can use a diesel one, just block off the unwanted return pipe.

Thanks - found the petrol part number which is NRC6905

Paddocks and LR Direct etc all seem to stock it. Bit pricey for what it is!

They are very pricey, also when I got a new one for the replacement tank I got as well it turned out the new tank is a slightly different depth so the new very expensive pickup had to be bent to get it to fit the tank.

Well I'm scratching my head here again.

Had the fuel pick up pipe out and examined it - it looks in great nick!! No dents, holes or noticeable problems. I even clamped off my fuel hose, put a foot pump on end of pickup pipe, then put it in a bucket of water and pumped the foot pump. No air bubbles or leaks at all visible!

All the fuel line also looks ok and no leaks are showing.

Does anyone think it could be the fuel pump? Or a split in the pump diaphragm? Can't see any other way air is getting in??

Metalmental said:

There are no air bubbles in the glass bowl but in the inline filter.

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Where is the inline filter is it on the feed from the tank or between the lift pump and carb?

Rodeo Joe said:

Where is the inline filter is it on the feed from the tank or between the lift pump and carb?

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Hi it is between the lift pump and carb.

If it was me I'd double check all the unions.