Low Fuel Sensor

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AustHaflinger
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Low Fuel Sensor

Post by AustHaflinger »

My haflinger has an after market VDO fuel gauge that works pretty well. As I have never pulled the tank out I assume the sender is on top of the tank out of sight.

I have the original low fuel light which I assume was operated by a sensor in the side of the tank down near the bottom. Now I have the wire for this and it is live and when shorted does light up the low fuel light. The hole in the side of the tank seems blocked with just a filler nut.

I would like to reinstate the low fuel light and spotted this sensor online https://www.prokschi.at/haflinger/fuel- ... 013-0.html

I assume this is the right one but can anyone confirm?

Thanks

Garry
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heinkeljb
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Re: Low Fuel Sensor

Post by heinkeljb »

I can't be 100% certain, but that looks like the correct item. I'll only be able to look in the parts book this evening when I get home.

The fuel gauge sensor is a wire wound resistor with an arm and a float. Access to it is via a panel on top of the tank. Undo 6 10mm nuts, pry it up off it's gasket (worth using petrol resistant gasket sealant as well as the gasket) and then manhadle the sender unit out if you need to,

John
Haflinger 703AP LWB 1973 - (Once owned by Lady Sutherland & Sons.) Now called "Lurch" !

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AustHaflinger
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Re: Low Fuel Sensor

Post by AustHaflinger »

Thanks John - just to clarify I am looking at the low fuel light sensor that goes in the side of the tank not the fuel gauge sender in later models that as you describe goes in the top of the tank.

Cheers

Garry
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Re: Low Fuel Sensor

Post by heinkeljb »

The only issue I have with the fuel light sensor system is that the by the time it lights up, you haven't got much fuel left in the tank! The gauge isn't much better, but at least you see the relative fact of the fuel level going down!

Just checked the parts book, that is the correct part, there is also a copper washer to go with it to provide the seal.

John
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AustHaflinger
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Re: Low Fuel Sensor

Post by AustHaflinger »

Thanks John - yes my VDO gauge works great but a light will tell me how many litres I have left in the tank when it comes on.

Cheers

Garry
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AustHaflinger
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Re: Low Fuel Sensor

Post by AustHaflinger »

I had an hour to spare so pulled out the fuel tank.

Here is a pic of it standing on its end.
IMG_20181204_192729.jpg
While mine does not drip you can see the petrol "varnish" on it where there is a minute leak that is evaporating before dripping. I was intending to seal the inside with tank sealer but I did not realise a small tank like this was baffled. I guess I just put the tank sealer in the centre section and it should work its way into the outer chambers - mainly looking at sealing the bottom inside seam.

I also spotted previous welding in the center front of the tank - so I guess like most it has rusted at some stage. While the inside of the tank is painted in red lead/oxide, where it was welded the metal is bare - so the tank sealer will provide a good seal for this metal.

What was interesting was that the tank was not fitted with a gauge sender - the previous owner just drilled a 2" hole in the top and put in a VDO cylindrical fuel gauge sensor that is held in with tech screws - crude but works.

I want to also put in a low fuel level sender so I looked at some old posts and see that Tony Hrelja in Melbourne has some so I will try to contact him tomorrow, if not then Prokschi in Europe.

garry
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heinkeljb
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Re: Low Fuel Sensor

Post by heinkeljb »

Gary,

If you find the post on my petrol tank issue, you will see that the problem stems from the fact that face of your petrol tank that has the welding on it is in fact, a double skin layer setup and that more than likely the drain holes which should allow an condensation / water from wading that get up there to drain out are probably blocked.

If you buy a petrol tank sealing kit which has three parts like mine had, then first one is used to wash the tank and get rid of any crud. Second is a rust remover, third is the sealant.

If you can pick up the tank when it is about a third full, then you can probably get about 90 % of the tank coated with the sealant.

Two biggest issue you will face are:-

1: That the fixed fuel pipe in the tank will fill up with sealant unless you can block it off inside the tank.
2: That it will all pour out the two holes on the top unless you can seal them. DON't use the PETROL CAP!!! this has little holes in it to allow air to be sucked in to replace the fuel as it is used and the sealant will seal them and as you know THE SEALANT IS DESIGNED TO RESIST MOST SOLVENTS! (If you had an old petrol cap you don't mind consigning to the scrap heap, you could use that).

When I got to the sealant stage, I spent 20 minutes turning the tank over and over until I thought it must have covered every surface. Just remember it flows like cold EP70 or hot Honey, so give it time to flow from one end of the tank to the other.

The version I used was white so it was easy to see where it had covered and where it had not. You will just have to guess regarding the parts you can't see behind the baffles - unless you want to cut the whole bottom off, coat the top part now you can see it. Weld the bottom bit back on, then coat the bottom part as now you can look through the two holes in the top to see what you are doing.

Best of luck!!

John
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AustHaflinger
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Re: Low Fuel Sensor

Post by AustHaflinger »

John - Thanks for those tips.

I am not wanting to coat the entire inside of the tank just the bottom seams and the area that has been welded previous so up to a couple of inches only. The welding in the tank was done at least 8 years ago and there is no rust on this bare metal so the tank has always had fuel in it and no water which is good.

At the moment I am waiting for the fuel to dry out before I pour the sealer in. Yes I will need to ensure the fuel pickup does not get sealant into it.

Interesting when I took the fuel line off the side of the tank - the banjo connection did not have any copper or fibre washers on it - it was a wonder it was sealing - and indeed that is maybe where the minute weep was coming from.

Cheers

Garry
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AustHaflinger
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Re: Low Fuel Sensor

Post by AustHaflinger »

Spoke to Tony in Melbourne - he does not have any low fuel senders :( looks like Danny (Vampyre) got the last one a few years back.

The Austrians want €40 for the sender which I think is OK but then want €67 to send it which is even for European postage a bit much for a cigar sized item.

Waiting for the Scots to get back to me now. Their shipping has been Ok in the past but we will wait and see.

At those shipping prices I might have to give the idea a miss.

Garry
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mechanical horse
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Re: Low Fuel Sensor

Post by mechanical horse »

He Gary,
I have just made a fuel tank for mine and made sure that all of the external seams were not leaking and then used a tank sealer on the inside. I blocked all of the threaded holes etc and then a minimum of sealer, nowhere the whole tin, just enough to seal the lengthwise seam and the 2 end plates and the bits of the original tank that have got the fuel sensor hole, the fuel outlet hole and the filler hole. I only put in less than a quarter of a cup full of sealer at the most and then watched through the filler hole as I wobbled the tank around and ran the sealer where I wanted it. I have put a baffle in mine as well but just estimated/guessed where the sealer was covering in the places I couldn't see
You maybe surprised as to how far this sealer spreads and I had plenty left over after covering the seams a dozen times and I just let it settle on one end of the tank to dry and harden. My pickup point for the fuel outlet is about 20mm off the bottom of the tank so I never got any sealer in there. If you do then you have got a huge problem as this stuff sets like armoured ceramic and would be nigh on impossible to get it out of the pickup pipe.
Work has stopped on my Haffie for awhile as I had a serious fire in my workshop which has caused lots of damage and expense a week ago. Probably a new workshop, garage, coolroom and equipment shed will be on the rebuilding list.The Haffie was right beside where the fire started and was to hot to touch for awhile but we managed to get it out but it is singed a bit as the covers I had on it caught fire. I may take some photos of it to show where I am up to on this rebuild if I can remember how to do it.
Good luck with the sealer and don't get any on your hands as there is not a solvent on earth that will move it .
Regards Rick.
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AustHaflinger
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Re: Low Fuel Sensor

Post by AustHaflinger »

Rick - too late :o about the time you put your post up I was finishing the job. I only got a small tin and it did the job fine. I put a plastic cap on the fuel pickup but on rolling the tank around the cap came off :? - did get a bit of sealer in it but an air hose on the other end blew it all out. I am surprised that there was not a prefilter gauze in the end of the fuel pickup to prevent large bits being picked up but then my tank had little garbage in it and everything was clean.

I got nice coverage over the inside of the tank so should be all fine.

Sorry to hear about your fire but glad the haflinger is OK.

cheers

garry
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AustHaflinger
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Re: Low Fuel Sensor

Post by AustHaflinger »

With the tank out my thoughts on a barely perceptible weep was confirmed. The bottom of the tank was never wet but was covered with varnish like you find inside a carb - so there must have been an exceptionally small hole and the petrol it leaked evaporated immediately leaving the varnish - wow carby cleaner really sorted it out.

The inner tank is now completely all covered by the tank liner and is nice and hard. Like all things, it was certainly easier to get the tank out than it was to get it back in. I got the tank all connected up electrically and back up in place with the mounting straps on but then the fuel pipe would not reach - looking around I could see that the tank was tilted forward a little so I undid it all and put in the fuel pipe loosely then put it all back and it went in OK.

20 litres of fuel in, no leaks, engine runs fine so any crude has been caught by the filters - i was surprised that there is no coarse gauze filter on the fuel intake in the tank to catch any big chunky bits but I guess it is not important - certainly my tank was absolutely spotless inside with no chunky bits floating around.

So all back and working fine. My plan to put in the low fuel light sender is on hold - I can get one from Austria but it is just too expensive with shipping. Dale from Haflinger Technik has my name down on his parts waiting list for one and will let me know when he gets them back in.

Garry
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Ole
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Re: Low Fuel Sensor

Post by Ole »

garrycol wrote:i was surprised that there is no coarse gauze filter on the fuel intake in the tank to catch any big chunky bits but I guess it is not important - certainly my tank was absolutely spotless inside with no chunky bits floating around.

Garry
A gauze filter would be nice in my tank. I have plenty of flakes from the old liner floating around. When they manage to lay flat against the end of the pickup tube the motor stops quite fast. Has happened so many times now that I keep one hoseclamp on the fuelfilter loose and have a short hose with me that I connect to it and blow back thrugh the fuel line to remove the flakes. It is on my to fix list.
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heinkeljb
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Re: Low Fuel Sensor

Post by heinkeljb »

Ole, the problem you have is the tank was sealed with a sealant back in the days when petrol had no ethanol in it. Ethanol eats the sealant and it comes off in flakes or long strings.

Make sure the new sealant you use is Ethanol proof.

John
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Ole
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Re: Low Fuel Sensor

Post by Ole »

Thanks for that information John. I thought it was only old age killing the tank liner.
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AustHaflinger
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Re: Low Fuel Sensor

Post by AustHaflinger »

One of the reasons I like dealing with Haflinger Technik. As indicated above they were out of stock and promised to contact me when they got them in - they did today.

Cost 38 pounds about the same as the Austrians at 40Euros - so $66AUD - but the Austrians want 67Euros to ship so total cost is $170AUD but Haflinger Technik only want 10 pounds so their all up cost landed in Aust is $84AUD - so all up the Austrian product is double the cost landed here over the Scots price.

There is a reason all my parts have come from Haflinger Technik - price and service.

Garry
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AustHaflinger
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Re: Low Fuel Sensor

Post by AustHaflinger »

And the part was sitting on my doorstep this morning when I got up - one week from Glasgow to Canberra by normal mail over the Christmas period - not bad at all.
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