The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => Frame => Topic started by: bakerlonglegs on 31.08. 2020 09:56
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Please may I ask for advice?
I have a ‘53 A10 plunger with a new Amal carb. My fuel tank connections are all leaking like crazy. They leak at the screw fixings which hold the spigots to the fuel taps, they leak where the fuel taps screw into the tank and the connection under the float bowl also leaks. They’re all very tight but I’m reluctant to really have at them like a gorilla because it feels wrong - they’re not engine mounts. I thought I would step away from the tools and ask advice before I break something.
I’m using fibre washers where the fuel taps meet the tank and top and bottom of the float bowl connection. I’m not using anything in the spigot screw connections to the fuel taps. Am I missing something? Should I be using some extra washers, gasket goo or other measures? I’ve attached some pics for your amusement, mickey taking is of course welcome!
Thanks
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I found soaking the fiber washers in brake fluid oil over night expands the washers & doesn't dry out helps..
Mind you mine STILL weeps.. Others may have another better solution?
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Have you tried PTFE tape in the tank boss
The pipe to the carb, I'm always a bit suspect regards those jubilee clips when you get down to the small sizes, they tend to squeeze the pipe off round (a new term I think), maybe try a plastic pipe that is a very tight fit and dip it hot water so it just slides in to the spigot's and look for a smaller type of clip like those below
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I really can't recall, but I probably used PTFE tape on mine. A quick search for best gasoline thread sealer found an article recommending against tape and suggesting this: https://www.permatex.com/products/gasketing/gasket-sealants/permatex-aviation-form-a-gasket-no-3-sealant-liquid/
That said, take a real close look at where the tap threads into the tank adaptor. There is a pretty good gap there between the fiber washer and the adaptor where the adaptor shoulder is not level.
For no certifiable reason, I don't like that type jubilee clamp where the threads are just stamped in versus punched. I don't think you can tighten them as tight, and I like to see some visible hose squeeze (uuuuh?).
Richard L.
EDIT: It's not actually clear to me if what I've called the "tank adaptor" isn't the "spigot" BLL references. Nevertheless, the condition is the same, internal thread not perpendicular to the shoulder.
EDIT, EDIT: The article for boaters where I read about the sealant: https://www.jamestowndistributors.com/userportal/document.do?docId=563
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I use petro tape on my threads
Works well for me
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I use petro tape on my threads
Works well for me
Interesting, I haven't seen that before.
Richard L.
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It's not actually clear to me if what I've called the "tank adaptor" isn't the "spigot" BLL references. Nevertheless, the condition is the same, internal thread not perpendicular to the shoulder.
Sorry Richard I was stuck for a name, Spigot I used to described whatever the pipe slides onto. the tap or the carb thingy, grey cells having a lie in today
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Lots of ptfe does for me. Those taps can be a bit rubbish, tho expensive and lovely to look at. Mine started leaking at the 45* angle, nudged by my knee, so keep an eye on them. Changed to BAP and no problems. Fuel pipes always worth changing regularly?
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BSA Bill is right. Small jubilee clips are a nightmare as the scroll area rarely matches the OD of the hose and cause leaks at each end of the scroll. I locate petrol hose on a stub in one of the following ways: C clip which is crimped at 180*, a narrow jubilee clip ( 3 - 4mm wide), a good push fit or two turns of copper wire, a twist and trim to length. The latter may look a little shade-treeish but it works very well.
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RD,
I went looking for crimpable C-clips and only saw O-clips with the crinpable zones 180 deg. apart. Are those what you meant? Those seem like a very positive way to seal hoses but d*mn hard to remove. I suppose everyone who's been playing with cars and bikes for fifty-odd years has done the copper wire bit. I don't know what the more roundy screw-tighten clamps are called (because I didn't bother researching when thumb typing) but they seem like they might be more practical service-wise. Am I correct?
The other thing in BLL's picture was the askew landing shoulder for the tap fiber washer. Any sage advice on how to remedy that?
Richard L.
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Richard - you're right - I meant O clips - no idea why I wrote C - completely different animal. It's been a long day is my only excuse.
Re reducer into tank - it's clearly cross-threaded (assuming it's the same thread). I'd first check it is actually the right thread (presumably bsp). Failing that, loads of PTFE or liquid thread sealant (great stuff, but sets too quickly for me and is a bugger to undo).
Addendum - those O clips are relatively easy to get off - squash the 'ears' inwards with pliers or pipe grips. I sometimes re-use them afterwards by opening them out over the end of a pry-bar or other suitable taper.
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Hi all,
Thank you very much for all your replies, advice and links, that’s given me a lot to look at. First thing I’ll ditch those cheap jubilee clips and take a good look at the reducer to tank gap. I’ll replace the old fibre washers on the float connector and soak the new ones first. That gasket gloop looks worth a purchase too.
Cheers!
BLL
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Hi
The first time I stripped my carb I put it back together and it pee'd out of the banjo feed. Took it off and flipped the washer over the other way and it stopped leaking, that was a copper washer though.
The tap reducers and spigots on mine took some sealing, PTFE tape on the reducers ( just on the bottom few threads) and a lot of farting about with the spigots, mine fouled the top of the float bowl on that side due to tap hole positions on the Indian tank I just fitted.
They seal like a tapered compression fitting so needed a bit of muscling tight.
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Try Dowty washers on your tap spigot into the tank they usually seal pretty good.
ELLIS
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G'day BakerLL.
As far as thread sealer goes I use Loctite 567 on all pipe thread fittings and sump plugs. It won't "lock" the thread but seals very well.
Cheers
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Just a reminder to anneal copper washers, to make them soft, just like a copper head gasket.
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Push on connections on banjo fittings rely on the fuel pipe to be a tight fit on the spigot. Clips and crimps are not to form a seal, more to stop the pipe coming off. Flanged connections need undamaged faces, and sealing washers that end up compressed, rather than threads bottoming out and not applying sufficient clamp force. This also applies to conical fittings, which can sometimes be lapped to remove scores and imperfections so they closely match...Brasso metal polish was what we used.
Tank/tap joint is the awkward one, especially if the tank has a bas***d thread as somebody's idea of BSP Thread.
Swarfy.
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Thank you all again for the advice. So I got stuck in and SUCCESS!! I now have a leak free fuel supply, thanks to the advice on here. This is what I did:
Replaced the jubilee clips with petrol pipe clips (Halfords 12-14mm) and, confirm, the fuel pipes are already nice and tight on all the spigots before using the clips.
Replaced the fibre washers on the fuel pipes banjo to float chamber and float chamber to jet block connections.
Checked and re-tightened the jet block.
Used Permatex Form A Gasket Cement on the threads for the reducers to the tank and the fuel taps to the reducers, as these won’t be coming off again any time soon. Word of warning - this is properly sticky stuff, use gloves when you’re applying it as it’s a bugger to get off skin.
Used PTFE tape on the fuel line to tap connections, as they will need to come off more regularly to take the tank off for service access, plus the taps and the connections are all new.
*beer*