The BSA A7-A10 Forum

Technical => A7 & A10 Engine => Topic started by: Dunney on 11.04. 2013 11:07

Title: Oil return union leak
Post by: Dunney on 11.04. 2013 11:07
For as long as I have had my 60 A7ss I have never been able to stop an oil leak from the banjo feed to the rocker box.

I am obviously doing something wrong so please can you all tell me how you fit it and what sequence of washers fibre/rubber/copper works for you.  I do have what I believe to be the correct thin nut which I believe is what is supposed to hold the whole thing in place.

Any advice very welcome

Dunney
Title: Re: Oil return union leak
Post by: Billybream on 11.04. 2013 12:24
Hi Dunney, and welcome to this great forum.
Copper washers are normally used, but make sure you anneal them, I have had success with dowty bonded washers on oil lines, these are metal outer with rubber seal inner. Banjo oil leak was recent forum topic and the leak was from the banjo soldering.
Title: Re: Oil return union leak
Post by: rocker21 on 11.04. 2013 13:02
another possible source of a leak is if the banjo is not down far enough then the oil pipe union nut bottoms out and you think it is up tight but it is not and you get a leak, which is not obvious where it is as it looks like the banjo but it not.
Title: Re: Oil return union leak
Post by: orabanda on 11.04. 2013 13:44
I agree with rocker21 re the position of the spindle (the distance it is proud of the rocker cover, on the LH side).

The amount that the acorn is screwed onto the RH end of the spindle, governs how much the LH side is proud.

Check that the acorn nuts are tight, as well as the banjo feed side bolt(s).

Richard
Title: Re: Oil return union leak
Post by: Dunney on 11.04. 2013 14:52
My fault.  Poor explanation of the problem.

The problem I have is not at the head, but at the tank where the feed to the rocker box connects.

Any ideas?

Dunney
Title: Re: Oil return union leak
Post by: a10gf on 11.04. 2013 15:04
tried a Search ?  ;)

http://www.a7a10.net/forum/index.php?topic=6943.0
Title: Re: Oil return union leak
Post by: Dunney on 11.04. 2013 15:50
Ah yes.  *doh*

And ah yes, intersting.  Will try that.

I am deeply indebted to the bloke who invented hydraulic bike lifts.  Trns this sort of fiddly job from a right sod and knee killer into manageable.

Will report back after I have done the timing, a job I hae with a passion.

Why do we do this?

Thanks
Title: Re: Oil return union leak
Post by: Joolstacho on 12.04. 2013 11:40
Hey Dunney, I feel your pain (especially in the knees!)
The only good thing about it is that, having removed and fitted the oil tank about 5 times in the last few days, I can now do it in a few minutes. A really annoying thing about this banjo connection is that the oil tank threaded pipe is relieved to a smaller diameter after the threaded section, so whatever sealing washer (on top of the banjo) you use has to go over the thread, but when it gets down to the smaller diameter relieved section it can just move sideways and float about. As you tighten the nut that holds it, the washer easily gets pushed aside and misaligned, potentially causing a big leak. I ended up assembling it all on the bench using sealant and a 'false' nut to hold the washer tight, leaving it overnight to allow the sealant to harden, this way I could make sure the washer didn't shift. Next morning I undid the false nut, fitted the tank and connected the lines without the sealing washer moving.
So why, oh why did they machine that relieved section into the pipe, what's the point?
Title: Re: Oil return union leak
Post by: Dunney on 12.04. 2013 12:12

So why, oh why did they machine that relieved section into the pipe, what's the point?

Well quite.  At least on my victor and A65 the oil tank features a separate stub to feed the rockers, how simple is that.  If anyone has an answer, please post to me on the back of a £5 point note.  Will persevere.

Dunney

Title: Re: Oil return union leak
Post by: Dunney on 12.04. 2013 12:16
Actually on thinking about it the answer is to probably copy what they did on the A65 and B44.  Next time I repaint the oil tank I will perhaps try to modify the return stub and fit a permanent piece of pipe on to which I can fit the hose to the rockers and completely do away with the banjo fitting.

Dunney

Title: Re: Oil return union leak
Post by: KiwiGF on 12.04. 2013 21:39
I had an oil leak in this area, suspected the banjo and spent a fair while cleaning up surfaces and  making up my own "laminated" washers using wadd punches out of 2 thicknesses of .8mm gasket paper, which worked fine by way but lucklily i pressure tested the tank and banjo job before fitting it and found the leak was actually a crack in the tank, in the seam right at the bottom, which i fixed with soft solder as i was off to rally the next day, it needs to be fixed properly but you how it is it might still be like that in a years time.....
Title: Re: Oil return union leak
Post by: iansoady on 13.04. 2013 10:54
Soft solder should be fine - International Norton piecrust petrol tanks were put together with it......
Title: Re: Oil return union leak
Post by: KiwiGF on 13.04. 2013 12:47
At the risk of being told off for going off topic... *dunno*    soft solder works great if put on thick enough my petrol tanks is held together with it......numerous leaks fixed somfar so good mainly cos the strap was not fitted i suspect....

Not sure how the oil tank seam was made originally.. hard solder?
Title: Re: Oil return union leak
Post by: Dunney on 14.04. 2013 10:42
Interesting KiwiGF.  Did it only leak when the engine was running or was it always dripping.  Mine only leaks when the engine is running which would not make me suspect the tank.

Not off topic IMHO.

Dunney
Title: Re: Oil return union leak
Post by: KiwiGF on 14.04. 2013 11:37
Hi dunney, the leak was pretty much there all the time but worse when running, the odd thing was i put half a litre of turps in the tank hung from the roof and no leak, it only showed when i pressured it a few lbs, using a washing up liqued solution to indicate where the leak was eg bubbles. Maybe heat opened the gap ...
Title: Re: Oil return union leak
Post by: BSA_54A10 on 14.04. 2013 11:59
There is solder and there is solder.
What you should use is wiping metal which is about 5 % tin & 95% lead.
This is quite flexable and is the type of material used to make up the pre WW 1 petrol tanks.
People read that tey were soldered and immediatly think of 50:50 or 70:30.
The last big use was for body filler before epoxy came on the market
Title: Re: Oil return union leak
Post by: Dunney on 14.04. 2013 12:06
Oh remeber someone showing me how to "lead load" body work.  That takes me back.

Dunney