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MG MG Y Type - SU Fuel Pump - Breather Hole.

I asked a question on the TC forum about the correct location of the breather hole in the main pump body. It's all very quiet over there - any fellow Y Typer care to comment? Sorry I don't know how to copy/paste/redirect etc from TC forum to Y forum, so I'll have to ask you to look at the post if you have time. Thank you! John.
J P Hall

John's original request was:
J P Hall, Queensland, Australia

Having stripped and cleaned an old brass-end LP pump, I'm half-way through reassembly when I think: the breather hole was at the bottom when I disassembled, but John Twist's article refers to making sure the breather hole is at the top. As a breather, I can see the sense of having the hole facing upwards, especially as this pump had spurted fuel out of the hole due to a failed diaphragm(!). But is the bottom the correct location, and if so, why? Thanks as ever ... John.
Paul Barrow

John

Please remember the caveat on the Technical Video page of "All the short videos on this page can also be found on YouTube, along with others that are more specific to a particular model such as MG MGA, or MG MGB. Although these videos are not specifically on MG Y cars, the principles are true and can easily be carried over and used on our cars."

The video you refer to is based on an MGB pump. With that said, irrespective of where you think the breather hole may have been John, I would follow John's advice and fit the hole to the top. The bottom is incorrect.

The Technical Videos can be found on http://www.mg-cars.org.uk/imgytr/umlvideos.shtml.

Regards

Paul
Paul Barrow

Thank you Paul - that's the video I had seen, so I'll do as you suggest and move the breather to the top. John Twist sure makes the points adjustment look easy! Regards, John.
J P Hall

According to burlen the breather was put in to take away fuel vapour etc,without it the vapour etc could find its way into the points chamber and possibly cause a problem which would be detrimental to the pump !!! they allso confirm the top position is the right one John. UMG624
JC Jebb

Thank you JCJ, I too thought I'd seen something from Burlen, but couldn't find it. So I lean back towards the topmost location for the breather hole in the case of points-operated pumps (with respect, Paul) - even though Cliff Knight's article in the imgytr tech section states "Note that the drain hole in the coil assembly should (be) the same side as the filter in the base".This would place the (drain) breather hole at the bottom, which worries me greatly.
I wonder whether Dave du Bois has a view??
Regards, John.
J P Hall

"Well now" ... Dave du Bois has put a very helpful comment on the TC list, for anyone who's interested. He explains why, in his opinion, the breather hole should be at the bottom, aligned with the filter location at 6 0'clock. I think we'll call it a draw. Regards, John.
J P Hall

John if you look in the SU Reference catalogue/workshop manual page 162/163 you will see pictures of two pumps with the vent valve as its called at the top of pump wen I get my computer back I will post a picture of the pumps. John UMG624
JC Jebb

Look forward to that John, as every document I've found specifies bottom (6 0'clock) location for the breather for the TC era pump. Yours, John.
J P Hall

This thread was discussed between 06/12/2016 and 09/12/2016

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