Are Dowty / bonded seals Fuel resistant ?

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marksman

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As title, I'm thinking of replacing the copper washers on my diesel spill pipe banjo fittings as I'm finding it difficult to stop minor weeping, If bonded seals are resistant to diesel they would be an ideal solution ?
 
I don't think that'll work, the sealing area is on the outside edge of the copper gasket, not the inner edge like a Dowty seal. I don't recall ever seeing them on fuel systems -Renault use them on sump plugs so there must be some hydrocarbon resistant versions - I just don't think it'll stop your leaks, you probably need new banjo unions.
 
Annealing the washers and refitting them should do the job, quenching doesnt make a difference but does clean them up better.
 
I don't think that'll work, the sealing area is on the outside edge of the copper gasket, not the inner edge like a Dowty seal. I don't recall ever seeing them on fuel systems -Renault use them on sump plugs so there must be some hydrocarbon resistant versions - I just don't think it'll stop your leaks, you probably need new banjo unions.
The dowty seals seal on the outside face as the rubber bit is proud of the steel washer, I use them all the time on sump plugs.
Highly recommend them.
 
I use them some of the time on sump plugs ;) The difference is that a sump plug & sump have reasonably flat and wide surfaces from the thread so the flexible part is compressed before the metal part stops movement and takes the torque to hold it in place, a banjo isn't tight to the thread and has little 'land' for the soft part of the seal to seal on. Unless there is seal and metal able to be compressed under the edge of the banjo, then it either won't seal, or will fail as the torque is not able to be maintained due to the metal part of the washer not being under compression.
 
I use them some of the time on sump plugs ;) The difference is that a sump plug & sump have reasonably flat and wide surfaces from the thread so the flexible part is compressed before the metal part stops movement and takes the torque to hold it in place, a banjo isn't tight to the thread and has little 'land' for the soft part of the seal to seal on. Unless there is seal and metal able to be compressed under the edge of the banjo, then it either won't seal, or will fail as the torque is not able to be maintained due to the metal part of the washer not being under compression.
Banjo seals are standard fit on scania sump plugs.
Will have to check out the banjo bolts as not paid any attention before!
I kown I used some to get a leak free joint on an old tractor fuel filter housing the other week.
 
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