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Does anybody know when this was introduced. This breather is the tube that vents into the car, under the left side of the rear seat.

Regards
Al

I think the bible mentions something about that vent. Not 100% sure though, its been a while since I've read it.

Cheers Abri, I'll take a look.

Al

66S wrote:Does anybody know when this was introduced. This breather is the tube that vents into the car, under the left side of the rear seat.

Regards
Al

Vents into the car! No you mean comes down back of the tank and into the rear floor so it goses under the car

they are a bit rubbish if the standard pipe is still on I changed mine and made sure it didn't come out

still dangerous in my eyes

I am asking about the SU pump breather RidingLow, not the tank vent.

Al

Don't know but my 69/70 mk2 has one. It seemed strange to me.

I think this vent goes to the back of the pump diaphragm. As the pump acts, it needs to allow air behind (non fuel side).

I don't think this type of pump would work without a vent.

SU must have realised this and rather than have an open vent in a very dirty position under the car, which could suck in water / muck and stop the pump, they added the small pipe and plastic vent fitting under the back seat on the vertical 'heel panel' from the floor.

That's my thinking on it anyway; so not a fuel vent 'out', but an air vent 'in' to the back of the diaphragm?

Whadya reckon

graham in aus wrote:I think this vent goes to the back of the pump diaphragm. As the pump acts, it needs to allow air behind (non fuel side).

I don't think this type of pump would work without a vent.

SU must have realised this and rather than have an open vent in a very dirty position under the car, which could suck in water / muck and stop the pump, they added the small pipe and plastic vent fitting under the back seat on the vertical 'heel panel' from the floor.

That's my thinking on it anyway; so not a fuel vent 'out', but an air vent 'in' to the back of the diaphragm?

Whadya reckon

I reckon your on the money Graham

graham in aus wrote:I think this vent goes to the back of the pump diaphragm. As the pump acts, it needs to allow air behind (non fuel side).

I don't think this type of pump would work without a vent.

SU must have realised this and rather than have an open vent in a very dirty position under the car, which could suck in water / muck and stop the pump, they added the small pipe and plastic vent fitting under the back seat on the vertical 'heel panel' from the floor.

That's my thinking on it anyway; so not a fuel vent 'out', but an air vent 'in' to the back of the diaphragm?

Whadya reckon

Different models of the 200 series SU pumps fitted to minis had slightly different internals, so I guess if it was designed with a vent, it probably won't work without one. Having said that, the vent will still work without the tube connecting it to the point where it enters the shell. This will just be more risky in terms of dirt getting in. (http://www.somerfordmini.co.uk/eshop/in ... age&id=162)

Al, I've had a look in my bible and couldn't find anything in the Mk1 section...might have missed it. Now that I think about it, Somerford had it on their catalogue as well, but I can't find it on there either. Sometimes they put parts in places that are not intuitive to find. Any way, I suppose if you can find out when pumps with uncovered vents were introduced, you'll have a start date for the vent tube connection. I'd hazard a guess that they probably ran until the mechanical pump was introduced? I know the AUF214 has an uncovered vent and I think that was the latest model of electric pump used.

Al, hope this helps (dated May 1964):





My NOS AUF201 pump has the breather connection. I'll try to take a picture this week.

Here it is, AUF201 with breather:

Thanks everyone, most helpful. I looked in the bible too but could not find any reference to the breather. It looks like it was probably introduced in the early part of '64, going by the bulletin and that would perhaps mean that all 1275 S's should have it.

Thanks again and regards
Al