Lotus Elan

Fuel leak

PostPost by: Robbie693 » Thu Nov 05, 2009 11:33 am

Hi everyone,

I've a problem with fuel leaking from the fuel pump outlet (to the carbs). I tighten the pipe and all is fine for a bit and then it works itself loose and starts leaking again. I have the braided type hose. Last time I had it apart I put some Blue Hylomar on the threads (inlet and outlet) and the pipe from the tank is fine, just the other side comes loose and leaks. I also have a problem with the domed cover on the pump (it's an all metal replacement type pump, rather than the original glass bowl type), which also come loose and leaks.

Can anyone recommend a threadlocking sealant I could use to fix this?

I'm considering replacing the pump incase it's the threads that are damaged (seems to tighten up ok though) but if anyone could give me some tips to try beforehand I'd be most grateful.

Cheers

Robbie
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PostPost by: Frank Howard » Thu Nov 05, 2009 2:51 pm

Robbie,

I question as to whether or not the threads are supposed to seal the connection. I had a similar problem with mine using regular metal fuel line. The end was flaired and the nut was supposed to tighten the flair on to the pump creating a seal. I finally figured out that the flair was not the correct connection and what I needed was a compression olive that fit around the metal fuel line. That did the trick as the nut compressed the olive around the fuel line and up against the pump. Is it possible that your braided hose actually has an internal connection that requires the use of a compression olive?
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PostPost by: alexblack13 » Thu Nov 05, 2009 7:21 pm

Hello Robbie,
You need to check the following. On the feed pipe to the carbs there should be an olive type fitting where the pipe enters the pump. The nut which screws into the pump compresses the olive onto the outlet pipe and also forms a seal with the pump. This is easily overtightened. Does the nut (Fitting) seam to screw right into the pump and 'bottom out' the shoulder of the fitting onto the pump? This means that the 'olive' which is a barrel shaped brass ring normally, has been compressed to its maximum. Tightning the 'bottomed out' nut further will not clamp the olive and you have a leak. The answer is to cut off the olive and fit a new one over a new section of the pipe. Make sure you fit a new nut also. If it still leaks then the pump seat where the olive seals is goosed and replacement is the answer.

You say the filter cover also leaks? This could be just the gasket needing replaced or a fault in the actual cover. Needs examined. Could it be just the cover leaking and making it look like the pipe also?

Anyway.. Hope you find it ok. I would remove the pump to the workshop for examination. These usually work well with no leakages.


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PostPost by: Robbie693 » Sat Nov 07, 2009 12:57 am

Frank, Alex - thanks both.

Looks like I need to check out the olive (if there is one). The backnut doesn't bottom out and I'm wondering if it's not been tightened enough to compress the olive. I'm very wary of over tightening into the Alloy body of the pump, what kind of torque should I be putting on here?

Also, what size is the olive and where's the best place to get one. Plumbers merchants?

Thanks again

Robbie
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PostPost by: alexblack13 » Sat Nov 07, 2009 12:18 pm

I think they are 1/4'' dia Robbie. Try an engineering supply company. 1/4 might be a bit small for the plumbers.
If you get stuck I will have a looksee if I have a few I can let you have.

let me know..

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PostPost by: Frank Howard » Sat Nov 07, 2009 1:22 pm

Robbie,

The 1/4" olive is a standard item found in the plumbing department at practically any hardware store.
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PostPost by: stuartgb100 » Sat Nov 07, 2009 1:58 pm

Be careful.

Over on this side of the pond, most/all outlets are pretty much solely metric.
From what I remember, a 6mm olive didn't work for me.

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PostPost by: alexblack13 » Sat Nov 07, 2009 6:55 pm

No 6mm will not do it. 1/4'' and 6mm are different sizes.

Good if you can get them at the plumbers. Hardware store is a good idea! never gave them a thought. let me know if you have difficulty, which I doubt. They are easy to obtain.

Have fun..

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PostPost by: Robbie693 » Mon Nov 09, 2009 10:17 am

Thanks everyone.

A quick search on plumbers supply merchants was fruitless but I found these on ebay after I read a previous post on here. Which ones would be suitable?

http://cgi.ebay.co.uk/1-4-brass-olives-pack-of-10_W0QQitemZ400082993797QQcmdZViewItemQQptZUK_CarsParts_Vehicles_CarParts_SM?hash=item5d26ce0285

http://cgi.ebay.co.uk/1-4-machined-brass-olives-pack-of-10_W0QQitemZ400082993783QQcmdZViewItemQQptZUK_CarsParts_Vehicles_CarParts_SM?hash=item5d26ce0277

One looks more shouldered than the other.

Cheers

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PostPost by: rcraven » Mon Nov 09, 2009 11:52 am

Try searching for olive on this site http://www.vintagecarparts.co.uk/search.phtml. (A direct link to the relevant page didn't work.)
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PostPost by: Frank Howard » Mon Nov 09, 2009 12:01 pm

Robbie,

I believe you could be making this more difficult than it has to be.

1. Turn off your computer.
2. Push yourself away from your desk.
3. Get into your car.
4. Drive down to your local hardware store.
5. Go to the plumbing department.
6. Find the department manager.
7. Ask him for a pack of 1/4" brass compression fittings otherwise referred to as olives.
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PostPost by: alexblack13 » Mon Nov 09, 2009 5:39 pm

Robbie..Just looked and I have lots of them. Send me your address and I will send you a few. Free! For nothing,Zilch,nought,Bugger all.. :wink:

PM me your addy and they will be on route to you tomorrow.

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PostPost by: Robbie693 » Mon Nov 09, 2009 10:33 pm

Thanks for the link Robert.

Fair point Frank :lol: , I just wasn't sure of which type to go for. I've seen a few different designs..

Alex, you have a pm

Cheers all,

Robbie
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PostPost by: Robbie693 » Tue Mar 02, 2010 9:57 am

Been a while :oops: but I finally found time to tackle the hose connections.

Quick question: When tightening a new oilve (on the spigot of the braided carb hose) do I do as one would do with a household compression fitting and tighten a full turn from finger tight?

I don't want to 'neck' the tube by over tightening :shock:

Thanks

Robbie
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PostPost by: oldelanman » Tue Mar 02, 2010 1:49 pm

Quick question: When tightening a new oilve (on the spigot of the braided carb hose) do I do as one would do with a household compression fitting and tighten a full turn from finger tight?


Hi Robbie,
That's way too tight even for a household fitting as you put it - you will crush the pipe. Make sure the olive slides freely on the pipe before you assemble it, finger tighten the nut then just nip it with a spanner. Check for leaks and nip it up a bit more if necessary. If you do overtightened it there is no way back.

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