Petrol tank breather.

[Ralph Whitaker]

Every time I go into the garage there is a strong smell of petrol which seems to be strongest around the o/s rear wheel, which is where the breather pipe terminates just in from the wheel arch. I am sure the tank is leak free because if it were leaking the smell would be strongest in the boot and that is not the case. I have used a length of copper fuel line and left it open at the end where it protrudes under the car, and it always seems wet on the end. Should there be something else fitted, like a one way valve, or should the opening of the pipe be reduced perhaps.

Also the seal in the fuel filler cap is rock hard. Are replacements available anywhere ?.

Ralph.

[iain]

If your cap sealing plate has the tiny hole in it, you could blank off the overflow........that certainly worked for mine, I had exactly that issue. 
Iain

Edited December 13, 2020 by iain

[peter clarke]

I removed the pipe from the top of the tank and crimped it in a vice near the banjo fitting till i could only just blow through it...........worked for me

[mikej]

Also suggest blocking off the drain pipe (or removing it) and use a fill cap with a breather 1/16" hole in the plate. Copy a later car cap.  Modern fuel won't help and you are loosing the the good part of the petrol, I have domestic appliances in the garage and was most concerned about one of them igniting the fumes which will lurk at ground level. A certain make of tumble dryer won't need much encouragement to start a fire! Gasket should be available and most important to prevent sloshing on corners and fuel getting into the boot.

MikeJ

[BlueTR3A-5EKT]

Is this a repro tank?

I have identical issues using two repro alloy tanks.  The makers do not fit the internal vent pipe system which crosses the width of the tank internally.

I have a drilled/vented fuel cap fitted now and have made a blanking plug for one tank. The other tank will have a sleeve to fit around the original banjo bolt to blank the original vent.

That has resolved the constant stink.

Peter W

[mike ellis]

This is one option that I am considering

https://www.tr-register.com.au/Files/technical/smellyfuel.htm

[Ralph Whitaker]

Thanks for the responses. I spent ages making my breather pipe but looks like it is best done away with. I will check the cap for a breather hole instead. Where can the seal be purchased for the cap?, cannot see them listed by the usuals.

Ralph

[David Owen]

Just double checking this is the hole that obviates the need for the vent to be fully functional?  I have the same petrol smell and will crimp the vent pipe if it is.

 

 

 

[Ralph Whitaker]

I assume it is David. Try blowing through it (length of rubber pipe pressed against the hole!). If it appears clear then I would think it is fine. Really only to let pressure out as the tank warms up and air in as fuel is used.

Ralph

[David Owen]

6 hours ago, Ralph Whitaker said:

I assume it is David. Try blowing through it (length of rubber pipe pressed against the hole!). If it appears clear then I would think it is fine. Really only to let pressure out as the tank warms up and air in as fuel is used.

Ralph

 

Thanks Ralph.  It's the fuel system.  I'd rather ask a naive question than do something that causes the system to malfunction.  Or not function efficiently.

[Ralph Whitaker]

Had a look at my fuel filler cap, and although made differently to the one pictured above it is the same general shape and does have a hole. The filler cap seal listed by Rimmers, although being of a similar shape to the underside of the filler cap, is not the same as the seal in my cap which is in the lower portion attached to the car and not on the cap. I have found some rubberised cork seals for BSA tank caps which seem to be the right dimensions so have ordered a couple of those, I will let you know how they fit.

Ralph.

[iain]

To confirm, that is the hole.

Iain

[David Owen]

2 hours ago, iain said:

To confirm, that is the hole.

Iain

 

Thank you.