The BSA A7-A10 Forum

Technical => A7 & A10 Engine => Topic started by: Joolstacho on 04.04. 2013 11:11

Title: Return line union leak
Post by: Joolstacho on 04.04. 2013 11:11
Arrgh! I've minimised most of the oil leaks on the SR, but the return line union at the oil tank is still *issing out, despite trying copper washers, fibre washers, crush washers in various configurations. It's a strange arrangement with the return line and rocker feed banjo union there together.
The parts manual shows just 2 washers. What gives? I bet it's simpler that I think!
Cheers
Jools
Title: Re: Return line union leak
Post by: lawnmowerman on 04.04. 2013 11:34
Hi Jools

Did you anneal the copper washers before fitting. Nowadays a lot of copper washers have been punched out of a sheet of copper leaving a ridge on the mating surfaces so it is worth flattening them on a sheet of emery paper before annealing.

Jim
Title: Re: Return line union leak
Post by: Joolstacho on 04.04. 2013 11:44
Yup, I always anneal before refitting.
Title: Re: Return line union leak
Post by: orabanda on 04.04. 2013 13:36
Reminds me of a long time spend trying to get the two washers either side of the oil tank banjo to seal.

I had half a dozen other A10's with the same fibre washers; they didn't leak, but this &%^$&% did!

After much close scrutiny, the problem was a poorly soldered piece of 3/16" copper tube into the banjo; however it appeared to be coming from the washers!

The banjo / pipe piece was purchased new!

Since re-soldering myself; no more leaks!!!

Suggest you check this possibility.

Richard
Title: Re: Return line union leak
Post by: Joolstacho on 05.04. 2013 10:58
Good tip Richard, I'll check it tomorrow.
Title: Re: Return line union leak
Post by: mayes on 05.04. 2013 13:27
when finishing to check they are flat lay on glass this is the best way i have tried to prove surface is flat John
Title: Re: Return line union leak
Post by: Joolstacho on 10.04. 2013 11:10
Got the *astard! (Richard, take a bow).
But here's the thing. The leak turned out to be at the banjo/pipe solder joint, not the actual banjo / oil tank union itself.
After reassembling the thing 3 times trying various types of sealing washer, I pulled it all out and pressurised the banjo and pipe with air and so found the leak. I desoldered it, cleaned it up, annealed it and resoldered it using silver solder. Job done.
Now for the last leak... Yes, that gearbox/primary case drip. I've tried to fix this one before, carefully aligning the sliding plate etc, but no good.
I believe there's an oil seal conversion for this joint? Anyone got a fix for this that doesn't cost a wad of money?
-Jools
Title: Re: Return line union leak
Post by: bsa-bill on 10.04. 2013 11:25
I have a return line leak in the same place, never thought of the line so thanks Jools I'll check mine now (well soon)

Quote
that doesn't cost a wad of money?
well fancy reading those words in a mail for old bikes  *smiley4* *smiley4*