onenyala
Well-Known Member
Following my post a couple of days ago regarding fuel coming out of the breather vent on a CAV filter I think I have now worked out the reason.
Last year when I changed the filter and re-assembled the glass bowl etc I turned the main fuel cock on there were no leaks.
This year I did the same job but when I opened up the main fuel cock I could see fuel entering the bowl. However as it filled diesel started spewing out from one of the rubber seals. I shut off the fuel took the assembly apart and carefully refitted it using the same filter which was now soaked in fuel.
I then opened up the main fuel cock fully. As a result the rate of flow into the filter assembly from the tank was faster than it could percolate through the paper filter due to it being already saturated. Result there was only one route the fuel could take, out through the breather.
Lesson
1. Be more careful fitting the seals.
2.If you have to have a second go at it with an already soaked filter only open the fuel cock a small amount to allow the filter to cope with the flow.
If anyone has anything to add please do so.
Last year when I changed the filter and re-assembled the glass bowl etc I turned the main fuel cock on there were no leaks.
This year I did the same job but when I opened up the main fuel cock I could see fuel entering the bowl. However as it filled diesel started spewing out from one of the rubber seals. I shut off the fuel took the assembly apart and carefully refitted it using the same filter which was now soaked in fuel.
I then opened up the main fuel cock fully. As a result the rate of flow into the filter assembly from the tank was faster than it could percolate through the paper filter due to it being already saturated. Result there was only one route the fuel could take, out through the breather.
Lesson
1. Be more careful fitting the seals.
2.If you have to have a second go at it with an already soaked filter only open the fuel cock a small amount to allow the filter to cope with the flow.
If anyone has anything to add please do so.