I'm looking for advice on making the oil tank connections on my B33 plunger as leak proof as possible. My set up on the return pipe is as shown on the Draganfly diagram. Should there not be a second fibre washer (25) between the banjo and the tank? The parts list suggests that there might be two.
On mine there is no washer 8 and the rocker feed banjo sits between parts 7 and 9 and seals with tapers, but how does nut 7 seal on to the threaded tube coming out of the tank? The end of the tube has a female taper but there's nothing in the nut to compress and form a seal. I'm wondering whether there's something missing/incorrect parts fitted.
Thoughts would be appreciated.
See attached parts diagram. The two banjo washers shown (items 63 and 12) are identical, BSA part no. 29-7971. There is a fibre washer between your nut 7 and the tank (nut 59 here). It's part no. is 65-8421. I can't remember what I put in mine - probably a just suitably sized standard fibre washer and it doesn't leak.
Sorry - wrong picture! See below.
Thanks Martin. The banjo washers make sense. I'll get a couple ordered.
Re fitting a fibre washer between nut and tank, this can't make a decent seal on mine because of the lumpy weld at the base of the thread where it enters the tank. I think the way to do it might be by wrapping PTFE tape around the thread. I can't see how they might have done it originally.
Definitely two fibre washers on a banjo.
The washer on the nut at the bottom, I would guess without having mine apart, that the washer sits at the top of the male thread, and seals inside the nut, so has to sit down inside the female thread.
Leave the PTFE tape in your toolbox!
From memory I think the fibre washer seals against the end of the tank stub inside the nut. It's not visible when assembled. Draganfly have them at 38p so I'd try one of those.
The width of the lip on the threaded outlet is 1.2mm. The width of the shoulder inside the nut is 1.5mm approx. If both surfaces are perfect its still quite an ask to get a fibre washer to seal well. Not one of BSA's best designs, but I suspect that as with many parts, they used what they had on the shelves, even if it was designed for another purpose.
Still, I'll make sure there's a good face on the outlet and give the washer a go.
Many thanks for your input.
I usually paint a thin coat of wellseal on both sides of fibre washers in these circumstances.
Pete