Hi everyone,

This is a sub-thread to my fuel leak thread a couple of days ago, but worthy of a new discussion I think.

The leak I referred to is coming from the carburettor, specifically during the engine upgrade that car had a larger car fitted, and upgrade to a Weber 28 (because of the engine tweaks) which has a fuel return line.

They have blanked off the return line using a 4" length of fuel hose, a jubilee clip to attach to the carb, and an M6/M8 bolt jubilee clipped to the end.

Fuel is dripping out of that length of hose at quite a rate, and I could simply tighten the jubilee clips (which I'll do in the short term) but I'm sure it will just happen again, so I'm looking for a more permanent fix.

A couple of other options have been suggested:

1 - Adding a T-section into the fuel in line, just before the fuel pump, and re-routing the return pipe back into the fuel line.

2 - Removing the hose that's being used as a block, wiggle out the brass piping that extrudes from the carb, and plug that with a bolt and JB Autoweld.

Any views in this? Has anyone used either of these fixes and have a procedure to follow?

Morning Pete;
On my car I have gone for the 'T' piece option. I have put a brass 'T' piece on the side of the engine bay, held in place by a couple of 'P' clips (1 either side of the 'T' piece, round the fuel line) and led the return pipe behind the air-intake tubing, and run it through a length of larger hose to protect it from chafe. This achieves 2 things--(a) it stops the fuel leaking and (b) by allowing the fuel to constantly flow, it helps keep it a bit cooler.
If your float chamber is being over-filled to the point that it is constantly leaking--(1) check that the float adjustment is correct, (2) that the needle valve isn't sticking and (3) unlikely, but is the fuel-pump over-fuelling? by changing the number of gaskets between the pump and the mounting spacer, this can be adjusted.

Hi Pete,

The fuel return on the Weber 28 is through quite a small hole so if a reasonable amount of fuel is issuing from the return pipe, I'm with Tom above.

Check your float, both the level and whether it's taking on fuel itself and not 'floating'

Also check your the needle valve. An occasional error when rebuilding these carbies is to omit the aluminium spacer where the needle valve body screws into the carby cover. If left out, the needle valve will not close even if the float level is correct.

Finally, it is possible to block the return completely without causing any problems.

My 2c,
Chris

Pete
My car runs with Weber 30 dgf and has the return blocked off, even with using a pierburg electric fuel pump there is no leak although the use of choke on start has to be very carefully controlled.

Ian.

the hobbler said:

Morning Pete;
On my car I have gone for the 'T' piece option. I have put a brass 'T' piece on the side of the engine bay, held in place by a couple of 'P' clips (1 either side of the 'T' piece, round the fuel line) and led the return pipe behind the air-intake tubing, and run it through a length of larger hose to protect it from chafe. This achieves 2 things--(a) it stops the fuel leaking and (b) by allowing the fuel to constantly flow, it helps keep it a bit cooler.

Click to expand...

Great, thanks Hobbler.

I've tightened the existing jubilee clips to get it running again, and I no longer have the fuel leak. That said, I will definitely 'upgrade' to this longer term (safer) solution.

Bambino said:

Hi Pete,

The fuel return on the Weber 28 is through quite a small hole so if a reasonable amount of fuel is issuing from the return pipe, I'm with Tom above.

Finally, it is possible to block the return completely without causing any problems.

My 2c,
Chris

Click to expand...

Thanks Chris. The jubilee clips had worked very loose, and the clip holding the bolt in was very loose indeed (I could turn the bolt with my fingers, it's a miracle it was still in place. I'll check the carb over next time I get it off.

the hobbler said:

Morning Pete;
On my car I have gone for the 'T' piece option.

Click to expand...

Hi Hobbler. Basic question, but what was the diameter of the T piece and fuel hose? I could just measure the hose that's on the carb, but suspect it's stretched a little and I'm keen to get this right (given that I'm messing with fuel lines!!!)

Hi Pete;
As far as I can tell, all fuel lines on the 500s (as standard) have a 6mm internal bore. You can get all the parts you need from the 'Car Builder Solutions' catalogue. Go on line to their web-site, they will send you 1 FOC--it is a very useful catalogue.

the hobbler said:

Hi Pete;
As far as I can tell, all fuel lines on the 500s (as standard) have a 6mm internal bore. You can get all the parts you need from the 'Car Builder Solutions' catalogue. Go on line to their web-site, they will send you 1 FOC--it is a very useful catalogue.

Click to expand...

I concur 6mm is the correct size. Another site that I have used in the past that is very good is this one. The link below shows the fuel line that I bought when I rebuilt the car. They also sell the brass T pieces and clips.

Tony

http://www.advancedfluidsolutions.c...aided-nitrile-fuel-hose-pipe-tubing-279-p.asp

Here's a photo of mine which shows the return line "T-ed" into the incoming line that Damian and Tony were talking of in the other thread.

nzbobc said:

Here's a photo of mine which shows the return line "T-ed" into the incoming line that Damian and Tony were talking of in the other thread.

Click to expand...

That's great, thanks everyone. I've ordered the t-piece, jubilee clips and fuel hose from the website quoted and will be completing this fix (as per the photo) as soon as it arrives.

You've all been a big help. Thanks.

It's a shame you don't get a fuel filter that has a Y feed in, as it would save the T-piece and jubilee clips and look a lot neater.

cheers, Steve

Pete,

If you end up cutting the fuel line before it enters the fuel pump, fuel will flow out of the line due to the tank being higher. Plan on clamping down on the hose coming from the tank or plugging it up while you make the other connections. You can disconnect the line at the tank, too. Although, all the fuel in the line from the tank to the rear of the car will still flow out.

Cheers,

nzbobc said:

Pete,

If you end up cutting the fuel line before it enters the fuel pump, fuel will flow out of the line due to the tank being higher. Plan on clamping down on the hose coming from the tank or plugging it up while you make the other connections.

Click to expand...

Great, thanks for the tip, I'm about to tackle the job and I'm glad I quickly checked in on the forum first!

Hi Pete145

How has the car ran since fitting the t-bar?

Chris

hodgy18 said:

Hi Pete145

How has the car ran since fitting the t-bar?

Chris

Click to expand...

It seemed to run very well, not noticeably different from being blanked.

I've since upgraded to a Dellorto twin choke carb.

Hi Pete145

I have bought the bits to fit so hopefully it will eliminate what I think is vapour lock from my symptoms and what I've read. So touch wood it will work for me.

Chris