Only the fuel in the supply pipe to the carb can do this, not the fuel already in the float chamber. Remember the float chamber is vented via a tube to the carby throat so the requirements for syphoning are not met.
Traction fuel pump
- Thread starter DoubleChevron
- Start date
Excellent.... the car is actually sitting behind me while I work from home.... So I just looked down the carby. It all seems tight, and the fuel pump will squirt fuel. So my issues are the pump draining off and needing to reprime itself before the car will start, not the fuel bowl draining off
I'm going to pull that pump back apart. I'm keen to see how the lever works. Has anyone tried "lapping" the bakelite pieces in the pump with something like a fine valve cutting paste to see if they can stop the drain back ?
No wonder "Trading Estate" went the one way valve.... how simple is that!
https://www.ebay.com.au/itm/2PC-6-8-10-12mm-One-Way-Non-Return-Check-Valve-Air-Fuel-Petrol-Diesel-Oil-Vacuum/333876311742?_trkparms=ispr=1&hash=item4dbc9436be:g:Q20AAOSwlSVgGQFK&amdata=enc:AQAFAAACgBaobrjLl8XobRIiIML1V4Imu%2Fn%2BzU5L90Z278x5ickkCrLl8erj3ATP5raQxjc%2F%2B2NbHrbmNaHIfq7THXHVBUT3G0Z3RVqkmkQTDd%2Ba83f2LN%2FQLqZQpxZbwDR2D%2FvOipORQmYLu0yVoL44CCsvqy9NNhgStgNAajPWBmo6XoLiDd9UuUfUmMJsG4jJlMOH8ZEIFW1vfLfchwAqbfNKGeuFF6CnuABC1NQOhzEHVt8hsKYL3WXjzzbDvf9elaVihAsxswlFwrXbLvy8xMXyk3ECoJF7Nxmoip3DoZKmZHh2Aa%2BR%2FfoEeJDNLXDo5lwVw5UfzGEXZVJMNm6NMBFDKp7u8Ui%2FpxXgxfncePScxkERn2Qcp5q5D2aT1%2BrL2Aa%2BFoseB7lpz7XK5tOGJ5%2F%2Baz98T%2FIsi7vzyw%2BbUdceEi6TMcolhHOa%2BFBeccHQlyRaKBMNxNEfHtVNsUCtoT3NxCOx5aVv%2FZ2F06hG%2FB5Kn5laGqiu7fFbY04gibVLZGm8Pu%2FfC2hl5v5AUXqd2k%2F%2B1u%2BeYO8Ud7umVrAImJ18MhwFQfCXWbzk%2BHKAylqiu%2FNnEhHiD798pBRWTYZK7L2Eh%2BRmqMlgNzSIel6Qt%2B8%2F0S1OhEUDYKS4J%2FwmYh%2FS%2F99smRAFJ0cUkS218AfIDhKndLfF12fi9RmuVO6pA%2BruTXXGlAQXsYkJL0nR1G0p7XWKNfUlCyvhUGrRWeqqr24dXXZ1OfOwID94m5CQsQjODYFJNtL6jLpb2rfb8JeTynhub7hpb3%2B%2Fyd6X9186wiLlxB6TTc6kCVwsr2ThZSWBzuI%2FBgm3R77Onz16Z4KdbT1Zwaocxv7oPn6o%2BRRyW%2FSgZJk%3D|cksum:3338763117425f8aa7e89d074a5cadf998ea62f155ad|ampid
L_CLK|clp:2334524
You could lap the valves on a sheet of glass and some fine wet and dry to ensure they are flat. But lapping their seats accurately would require some specialised gear.
Your pump is quite different from mine as I cannot remove the valves from the body without prising out brass retainers. It looks like yours is a pump from a six. What diameter is the pump body?
Your pump is quite different from mine as I cannot remove the valves from the body without prising out brass retainers. It looks like yours is a pump from a six. What diameter is the pump body?
I think its light 15.
https://www.cas-shop.com/en/product/petrol-pump-repair-kit-sev/
this is the pump kit that would match it. It would be about 10cm across the body. The Big 6 probably has the same pump ? I assumed its block was just a traction block with two more pots added
The kit contains everything. The filter mesh, the "O"ring for the glass top, the small cork gasket is a plate inside the pump you can unscrew to remove the two bakelite pieces and springs.
The intersting bit is I'm being offered boat fuel pump primers and one way valves if I open that fuel pump page. So I'm certainly not the only person with a traction that drains its fuel back to the tanks
That CAS page explains my query! It is for an SEV pump! Mine are Guiot pumps.
I actually have an SEV pump here. I always thought it was from a Six. Could you please tell me the diameter of the pump body? If it matches this one here then you can have it for a spare.
I actually have an SEV pump here. I always thought it was from a Six. Could you please tell me the diameter of the pump body? If it matches this one here then you can have it for a spare.
Last edited:
I fitted a push button under dash connected to an electric facet style pump to our Alfa, to prime the factory pump after sitting for a week or so. Works well.
Re the tractions, its possible the lines to the tank may have a pinhole in them which lets in air and makes it worse
Its about 10cm across the body. unless you break the glass, I can't see a pump ever wearing out while you can buy the rebuild kit ?
I'm going to check and see if I can get the primer lever working and will fit a one way valve. This really is a minor issue compared to all the other work I'll need to do ot the car
Doesn't the traction have hard lines back to the tank? It maybe pinholed, I'm not sure how to check for that one unless there is obvious wetness. One gentle suck on the line gave me a delightful mouthful of petrol, so there certainlly isn't any big leaks in the line to the tank
Same dimensions as the one I have here! Flexible line from under the wheel arch to the mainline under the floor pan.
It would be good to have a spare with a good glass. Yours if you want it! It is of no use to me as I have spares of the Guiot type as fitted to my car.
Also has a good priming lever!
It would be good to have a spare with a good glass. Yours if you want it! It is of no use to me as I have spares of the Guiot type as fitted to my car.
Also has a good priming lever!
I believe there is also a short piece of flexible line from the fuel pickup to the hard line on top of the fuel tank, which leads to the wheel arch. This is accessible through a small hatch in the floor of the boot.
Yes if you have a large boot (trunk) model. Shane's is a 51.
that sev fuel pump only uses about 2/3rds of the cam to lift the diaphragm from the manual lever, so I bent the lever so it clears the chassis rail and spring stop on the side of the pump. it now easily lifts fuel from the tank. Unfortunately as soon as I started the car ..... I found the petrol pump dripping copious amounts of fuel while the car was running. Not surprisingly the diaphragm has obviously torn/holed..... well it is probably 70years old!
So if you have one of these old sev pumps, you might need to bend the lever so it clears the chassis and spring stop on the pump before it will lift petrol from the lever.
So if you have one of these old sev pumps, you might need to bend the lever so it clears the chassis and spring stop on the pump before it will lift petrol from the lever.
It may be more suitable for you to install a British AC pump that was fitted to the Light 15 etc. They are very dependable and still easy to get parts. The do lack the nifty glass fuel bowl however. They have a very robust hand priming lever. I have several for you to choose from and a new set of valves and diaphragm!
I probably have pumps here from the ID19 that will fit as well
See how the lever is bent now. unfortunately the lever return spring broke as I re-assembled it.
The diaphragm is just amazing. Still supple and excellent. There must be 5 layers there, none of which are holed.
See the tag at the top of the diaphragm in the photo. It has a staple through it that holds all the layers of the diaphragm together. Its my assembling that caused the leak.
The reason it can leak on reassembly is that stapled tag has nowhere to go between the two halves of the pump, and must get "squished" as shown to not cause a leak. You couln't cut this off as then the diaphragm would be very difficult to assembled (all 5 layers, the big washers both side need to be lined up and screwed down at the same time).
The pump works perfectly now .... but check this out.
Hear the tapping valve ..... the fuel pump lever is bouncing in unison to it .... So I check with my stethoscope ( ... ok, ok, a long screw driver )..... Its the fuel pump that taps like a wide valve, not a valve!!
See how the lever is bent now. unfortunately the lever return spring broke as I re-assembled it.
The diaphragm is just amazing. Still supple and excellent. There must be 5 layers there, none of which are holed.
See the tag at the top of the diaphragm in the photo. It has a staple through it that holds all the layers of the diaphragm together. Its my assembling that caused the leak.
The reason it can leak on reassembly is that stapled tag has nowhere to go between the two halves of the pump, and must get "squished" as shown to not cause a leak. You couln't cut this off as then the diaphragm would be very difficult to assembled (all 5 layers, the big washers both side need to be lined up and screwed down at the same time).
The pump works perfectly now .... but check this out.
Hear the tapping valve ..... the fuel pump lever is bouncing in unison to it .... So I check with my stethoscope ( ... ok, ok, a long screw driver )..... Its the fuel pump that taps like a wide valve, not a valve!!
https://classiccarbs.com.au/Classic-Fuel-Pumps-Repair-Kits-Diaphragm-Kits-Fuel-Pump-Parts
These guys usually have stuff like diaphragms, for most model pumps carbs etc. not NOS junk new & meant for use with E10.
Not that I ever use or would recommend that stuff's use in our cars.
These guys usually have stuff like diaphragms, for most model pumps carbs etc. not NOS junk new & meant for use with E10.
Not that I ever use or would recommend that stuff's use in our cars.
Nice, this one doesn't actually need a kit ( think ....
). .... I'm just going to replace it. I'm not putting up with a fuel pump that makes noises like a wide valve