Technical Fuel filter removal

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Technical Fuel filter removal

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Nov 28, 2019
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In the manual the fuel filter removal looks pretty straightforward but it doesn't mention removing pressure from the system first.

From what I've seen elsewhere one method is to have the engine on with the fuel pump fuse removed and then just let the engine die. Is that the best way to remove pressure?
 
In the manual the fuel filter removal looks pretty straightforward but it doesn't mention removing pressure from the system first.

From what I've seen elsewhere one method is to have the engine on with the fuel pump fuse removed and then just let the engine die. Is that the best way to remove pressure?
As long as the ignition has been off for a few minutes, I have never experienced any major issues changing fuel filters petrol or diesel regarding pressure release. I assume by now you will have sorted it.;)
 
Fuel will go everywhere, look away when you pull the hose off.
 
Fuel will go everywhere, look away when you pull the hose off.
Like undoing a warm/hot rad cap , if you are careful and do it slowly allowing a controlled release of pressure and common sense then little risk, maybe with a rag over it to release any residual pressure.
Regarding radiator caps, the main thing to be aware of is as pressure is released this can allow the water to boil as that is the reason for a pressure cap, hot water doesn't damage engines it is when it is allowed to boil as that causes localised hot spots and cracked heads etc.
As I recall for every lb of pressure the water boils at 1.5 degrees Centigrade higher. Vice versa with low pressure which is why mountaineers can't make a good cup of tea . There is a bit of useless information;)
 
In the past I've changed the fuel filter on our then Tempra 1.8ie and never had a problem with excess pressure. The fuel filter on the Tempra is an aluminium canister with banjo connections at either end. Hint/tip for Tempra/similar fuel filters. These are a pig to get sealed and often leak around the copper washers. To solve this problem then anneal the new washer first. Well away from the car heat washers with blow lamp to red hot and allow to cool naturally in free air.

If the car has been left to stand for a while then the pressure gently leaks off. As far as I know there are no one way valves in the "B" fuel lines or fuel pump. The pressure is only built up when the fuel pump runs. With the ignition off then the fuel pump will not be running so the pressure will not be there after a little standing time.
 
In the past I've changed the fuel filter on our then Tempra 1.8ie and never had a problem with excess pressure. The fuel filter on the Tempra is an aluminium canister with banjo connections at either end. Hint/tip for Tempra/similar fuel filters. These are a pig to get sealed and often leak around the copper washers. To solve this problem then anneal the new washer first. Well away from the car heat washers with blow lamp to red hot and allow to cool naturally in free air.

If the car has been left to stand for a while then the pressure gently leaks off. As far as I know there are no one way valves in the "B" fuel lines or fuel pump. The pressure is only built up when the fuel pump runs. With the ignition off then the fuel pump will not be running so the pressure will not be there after a little standing time.
I agree with s130 , servicing a certain age Toyota Corolla with similar washers and in a awkward position half through the n/s wheel arch and half at the bottom of the bulkhead a right pain, but annealing softening the copper would help sealing (suppliers should send the right grade of copper).
In the old days motorists would overhaul their engines and always annealing their solid copper head gaskets to reuse them.
 
The pressure wont be the problem, liquid loses pressure as soon as it leaks, the pipes and hoses will be full, that's what will run out and cover you.
 
The pressure wont be the problem, liquid loses pressure as soon as it leaks, the pipes and hoses will be full, that's what will run out and cover you.
Yep there will be fuel leaking out. Worst is normally the filter so depending on access space it it best to release one side/pipe first and drain the filter down into a jar. Because of pipe bends and elevation changes then usually the fuel from the pipes is minimal but certainly one should be prepared for it.
 
In the end I removed the fuel pump relay and then turned the engine over. A tiny bit of fuel came out when I took the filter off. Thanks for all your comments
 
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