properjob
Well-Known Member
The connection between my fuel shut off tap and the tank is slowly weeping diesel fuel.The joint has been made using PTFE tape. What should be used on fuel line fittings to ensure a leak free joint ?
Diesel weeping from joint.
- Thread starter properjob
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Caer Urfa
Well-Known Member
You do not say if pipework is copper or rubber.
For metalic fittings say hosetail to filters etc., I have been using Rocol oil seal for years (available from most good plumbers merchants) on all my diesel fitting joints with no leak problems, but leave overnight to set, a tins not cheap but good!
If 'rubber pipe' to hosetail fittings a good jubilee clamp should be more than enough with the correct sized pipe and hosetail.
VicS
Well-Known Member
You do not say what type of joint it is.
If it is a tapered thread joint then ptfe tape ought to seal it. You could step back in time and use hemp and a jointing compound.
If it is a parallel thread then it should tighten onto a joint washer. Annealed copper perhaps but more likely a fibre washer.
If it is a tapered thread joint then ptfe tape ought to seal it. You could step back in time and use hemp and a jointing compound.
If it is a parallel thread then it should tighten onto a joint washer. Annealed copper perhaps but more likely a fibre washer.
properjob
Well-Known Member
The shut off valve has a male 1/4"bsp fitting screwing into a female 1/4"fitting welded to the stainless steel tank. I assume that both have parallel threads, but until I drain the tank I can't examine the fittings.
Thanks.
Thanks.
dingdongs
Well-Known Member
loctite 577 is the one.nothings getting past this and £6 on ebay.
Malish
Well-Known Member
I would avoid PTFE and use an anaerobic jointing compound like Loctite 577 - more professional. There is always the risk with PTFE that some fragments are released into the fuel after the joint is made (and end up trapped in something expensive); that said, in this specific case there shouldn't be an issue as I presume you have a filter or two between the tank and the fuel & injector pumps.
RobinBirch
Well-Known Member
Another vote for a jointing compound not PTFE. Try Hylomar Universal Blue -
oldharry
Well-Known Member
Dont use PTFE tape on a diesel joint. It ends up breaking up and causing problems. A taper plug should not leak, but can be sealed with jointing paste like Hylomar, as suggested.
Compression fittings ( i.e with a compressible olive) should not have any sealant applied, and if a good metal to metal seal is no longer possible should be replaced.
Ordinary screw in fittings need a suitable sealing washer of either fibre or copper. Again if a good seal can no longer be made, replace it.
Finally, are you sure it is the joint that is leaking, and not the tap itself? Cone taps wear and leak, Slide taps have a small fibre washer which wears out. In either case replacement is the only solution, though if the tap can be dismatled, a smear of grease on the moving faces may put things to rights. And no, the fuel does not dissolve the grease - dont know why, but it works!
Compression fittings ( i.e with a compressible olive) should not have any sealant applied, and if a good metal to metal seal is no longer possible should be replaced.
Ordinary screw in fittings need a suitable sealing washer of either fibre or copper. Again if a good seal can no longer be made, replace it.
Finally, are you sure it is the joint that is leaking, and not the tap itself? Cone taps wear and leak, Slide taps have a small fibre washer which wears out. In either case replacement is the only solution, though if the tap can be dismatled, a smear of grease on the moving faces may put things to rights. And no, the fuel does not dissolve the grease - dont know why, but it works!
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