Replace fuel line banjo - epoxy resin?

Technical advice Q&A

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ChipChipChipper
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#1 Replace fuel line banjo - epoxy resin?

Post by ChipChipChipper » Tue May 14, 2019 12:05 pm

We need to replace one of the three banjos on the fuel supply line to the carbs on our S2 4.2l 1970 2+2. We used an electric flame to unsolder the existing from the pipe. I had to purchase a new banjo from ebay as SG Barrat didn't have the carb banjo - they only have the pump and filter banjos - and went for steel over brass. We now need to reattach the new banjo onto the fuel line and are thinking whether epoxy resin will be suitable or whether to use aluminum solder. Any thoughts / experience to share? Thanks
Ian
1970 S2 2+2 4.2l

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MarekH
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#2 Re: Replace fuel line banjo - epoxy resin?

Post by MarekH » Tue May 14, 2019 5:23 pm

If you had purchased the brass fitting then you could have just soldered that back together very easily. My advice would be to return the item and do the job properly.

I don't think epoxy resin will automatically bond well to either material and have no confidence in its long term ability to absorb the change in vibrations at the metal-epoxy joint, its unknown variation with hot-cold heat cycling, UV resistance, its contraction/expansion properties at zero degrees centigrade versus eighty degrees centigrade or its resistance to petrol and all of the additives which may be added to petrol either now, or at any date in the future.

kind regards
Marek

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mgcjag
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#3 Re: Replace fuel line banjo - epoxy resin?

Post by mgcjag » Tue May 14, 2019 6:21 pm

Hi Ian...look up Burlan SU....get a brass one and solder on as Marek advises....Steve
Steve
1969 S2 2+2 & Building a C type replica

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ChipChipChipper
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#4 Re: Replace fuel line banjo - epoxy resin?

Post by ChipChipChipper » Wed May 15, 2019 9:27 pm

Well argued Marek - all good points - and thanks Steve. The banjo is back in the post to the supplier and I’ll get a brass one to solder on.
Ian
1970 S2 2+2 4.2l

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ChipChipChipper
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#5 Re: Replace fuel line banjo - epoxy resin?

Post by ChipChipChipper » Mon May 20, 2019 9:59 am

I can’t seem to find in any manuals whether the banjo should be soldered on or needs welding in with aluminium rod. What’s he best way to attach the banjo to the fuel line? (Which I assume is aluminium given its weight and malleablity). Thanks for your help
Ian
1970 S2 2+2 4.2l

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ChipChipChipper
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#6 Re: Replace fuel line banjo - epoxy resin?

Post by ChipChipChipper » Mon May 20, 2019 8:19 pm

Sorry to ask such as basic question but it’s been a while since I worked on this engine. Any pointers much appreciated as it seems to be a gap in the books I have.
Ian
1970 S2 2+2 4.2l

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mgcjag
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#7 Re: Replace fuel line banjo - epoxy resin?

Post by mgcjag » Mon May 20, 2019 8:58 pm

Hi Ian.....the banjos are soldered on...i dont know what with.....this info would not be in the service manual.....ideally take it to a small engineering workshop.....they can look and asses the best way to solder...Steve
Steve
1969 S2 2+2 & Building a C type replica

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cactusman
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#8 Re: Replace fuel line banjo - epoxy resin?

Post by cactusman » Mon May 20, 2019 9:12 pm

I'd guess Mr Whittaker would have used the cheapest method.....plumbers solder :bigrin: readily available from plumbers merchants along with flux.....trusty lead-tin alloy solder!
Julian the E-type man
1962 FHC
1966 MGB....fab little car too

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ChipChipChipper
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#9 Re: Replace fuel line banjo - epoxy resin?

Post by ChipChipChipper » Mon May 20, 2019 9:41 pm

Thanks both. Well it didn’t come off with a blowtorch - we had to put an electric flame on it. It made me think it must be something other than plumbers solder. But the torch is a bit old so I’m not sure it was at normal temp. The joys of winding up a mothballed workshop with old equipment. I’ll take your advice Steve and see if my local garage has some unobtainium I can borrow for it! Thanks
Ian
1970 S2 2+2 4.2l

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MarekH
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#10 Re: Replace fuel line banjo - epoxy resin?

Post by MarekH » Tue May 21, 2019 6:37 am

It was probably silver soldered, as the metals may have been too unlike in properties and not have enough copper in one of them for regular solder.

kind regards
Marek

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mgcjag
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#11 Re: Replace fuel line banjo - epoxy resin?

Post by mgcjag » Tue May 21, 2019 7:07 am

Hi Ian...as Marek says probably silver solder...a standard type plumbers blowlamp wont get hot enough.....they usually use Butane.......you will at least need a Propane torch which gets much hotter......an engineering shop will have a oxy torch for this and brazing etc.....they will also be able to look at the two different metals to asses for what flux and solder will do the best job...Steve
Steve
1969 S2 2+2 & Building a C type replica

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paulsco
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#12 Re: Replace fuel line banjo - epoxy resin?

Post by paulsco » Tue May 21, 2019 12:23 pm

It probably is silver solder, but I soldered mine on with ordinary plumbers solder and it seems fine.

It does not need to stand very high pressures and won't get all that hot in use for this to be a problem.

As Steve says, silver solder requires much more heat to make a joint.

Paul
65 Series 1 FHC, 68 Jaguar 340

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