Replacing Fuel Tank

[andyhodg]

Hi All

Having spent the afternoon removing the fuel tank due to a leak I found that the bolts in the centre of the diff mounts are over long causing the end of the bolt to fret against the tank. This is what caused the leak. I intend to rplace with a Andy Whiltshire tank. A few questions:

What is the correct arrangement underneath the tank? The straps where fitted on top on the felt but I felt the this arragement did not give enough clearance to the diff mounting bolts.

The drain plug was a bsp taper plug (1/4" BSP?) with no apparent sealing arrangement. Is this correct?

How should the banjo seal against the tank? the existing arrangement is a copper washer but I think it was leaking.

Should I use any sealant when I reassemble the banjo? If so what is the best sealant? I was considering Welseal.

Many thanks

Regards

Andy

[gerrym]

Andy, replies to some of you points:-

BSP thread, it's a taper thread so thats fine for sealing against the low pressure ( less than a couple of feet). Usually there should be a couple of turns of ptfe tape on a taper thread.

Tank mounts and straps. Like, you I found that the tank was not quite high enough from the diff mounts. I also wanted to have captive bolts heads secured to the tank straps. This means that when I remove the tank I only have to go under the car and undo 4 nuts and then the tank complete with the straps comes out in one piece. To do this I needed 1/2" spacers between tank bottom and the straps.

Regards

Gerry

[rdssdi]

Andy

I replaced my tank with a Axminster replacement. My tank was made to slightly lower height to provide room for the Newton breather vent valves and Mocal check valves.

Even with these improvements I continue to have fuel odor problems. As soon as weather permits I will remove the rear seat back and all other trim and inspect the tank for leaks or seepage.

I used -6 connections for fuel outlet and breathers.

As you will see I used closed cell neoprene foam instead of the jute padding. I felt the jute would capture any fuel leaks and not easily dry out. It appears I placed the foam under the brackets.
Photos attached.

Bob

[andyhodg]

Bob

Thanks for the information. Where did you get the neoprene foam from? I am considering using a camping mat. Any thoughts?

I have had to remove and dispose of the jute felt as it was soaked through with petrol!

Regards

Andy

[elansprint71]

andy,
I've used a closed-cell camping mat for the saddle between chassis and body and it was fine for that application; however I'm not sure how it would stand up to petrol. It's cheap enough to buy one and try it though!

[rdssdi]

I bought 3/8" closed cell neoprene from a foam supply company here in the U.S..

If the camping mat is closed cell neoprene I do not see why it would not work.

Bob

[davidj]

Bob,

You have some serious earthing straps on that tank!

D

[gerrym]

Bob, like you I had some petrol odours from the tank. I thought it was down to old lines so replaced them with high quality Aeroquip AQP elastomer hose, specifically marketed as suitable for petrol. Still had issues.

I then made up a small test tank with a meter long hose loop joined back into the tank (the tank was a small pressure vessel probably good for several hundreed psi).

Various test hoses were connected to the tank, and the tank 1/3rd filled. This was put into the wife's hatchback over summer (she and the kids have a much more sensitive nose than me).

The only hose that had no odour (ie no vapour permeation) was teflon lined wire armoured hose (I bought this from Think Automotive). The only way to join this hose is via purpose designed JIC fittings. My plumbing for the smaller lines in now all via teflon lined hose, connected via JIC fittings. The exception is the filler hose and that too is on my long term list to convert to Teflon.

Conclusion, with a petrol tank system effectively inside the car (as opposed to most cars where the tank is under floor, a very high standard of plumbing and connections is required to eliminate petrol odour caused by permeation through elastomers.

Regards

Gerry

[Robbie693]

Interesting Gerry,

Is this the same type of hose that is often used on the carbs?

How did you attach the fittings to the tank?

Cheers

Robbie

[gerrym]

Robbie, beware: just because a hose has a stainless covers tells you nothing about the liner or hose construction. Check with a reputable supplier and get a branded teflon (ptfe) lined hose if you are going down this route.

For the tank connection, I bored out JIC swivel fitting to match the plain stubs on the tank. These are loctited (correct grade) in place. If you took the tank to someone who knows what they are doing (correct precaustions include rinsing and maintaining an inert gas atmosphere), they could be silver-soldered in place. Alternatively treat yourself to a new tank with the JIC fittings already in place.

Regards

Gerry

[rdssdi]

Quite interesting.

I used rubber fuel line for the breather vents.

Since the filler elbow is most likely available only in the rubber version, I plan on removing it and reattaching with Hylomar. I feel that much of the "seepage" is at the joins.

What is the name of the teflon hose you used? I assume I could use it to replace my present vent lines.

When I leave the windows closed and the trunk (boot) closed the fuel odor builds to a very high level. I will inspect the tank as indicated. Most likely this weekend.

Bob

[gerrym]

Bob, speak to Think Automotive, Fay at Speedflow etc

here's some guff from Think. Have a "think" about electrostaticsand read the bit about Aeroquip 666

Gerry

"Conventional brake hoses, manufactured in rubber with textile reinforcement, are permitted to have a significant amount of volumetric expansion, that is they swell under pressure, this leads to a soft feel to the brake pedal, acceptable in a road vehicle but not for competition.
On racing vehicles, this has lead to the universal usage of smooth bore PTFE (Teflon ? ) hose with normally a stainless steel. This hose has the added benefit of lightness, strength, high temperature resistance and protection from stone damage.
We call it " Moquip TFE ", Aeroquip " TFE racing hose " or " 2807", Aeroquip Aerospace " 666 ", other brand names are " Speed-Flex ", 600 ", and " 411 ". They can be had with re-useable or swaged on fittings. With the exception of Aeroquip Aerospace, hose and fittings are interchangeable between brands.
Some countries, not the UK, insist on tests for brake hoses. The TFE hose assembly passes all the tests except the whiplash test which ensures that the hose is suitable for withstanding large wheel movements on vehicles doing hundreds of thousands of miles, quite sensible, but not relevant to competition motoring. Some hose specialists have recently come up with complicated assemblies allowing the hoses to pass the test, but generally speaking, they are not suitable for high mileage road usage.
These hoses are also suitable for oil pressure gauge lines, fuel injection pipes, power steering hoses and, because of their high temperature capabilities, on turbocharger oil feed and return lines.
Aeroquip TFE racing hose
Performance & dimensions.
Temperature
range -73?C to +232?C.
Pt No
Hose ID
Hose OD
Working Pressure
Burst Pressure
Bend Radius

FBC0300
0.13"
0.25"
3000psi
12000psi
1.50"

FBC0400
0.19''
0.30''
3000psi
12000psi
2.00"

FBC0600
0.32"
0.42"
2500psi
10000psi
4.00"

FBA0800
0.42"
0.54"
2000psi
8000psi
5.25"


Sizes. Available from -3 to -16 but only -3,-4,-6 and -8 are relevant to vehicle applications. -3 is used for brake hose applications, -4 for clutch due to greater fluid transfer requirements and for turbocharger feeds, -6 & -8 for power steering and turbocharger drains.

Aeroquip 666 Aerospace hose
Similar to above but made to closer tolerances and tested to Military standards. The Teflon liner is electrically conductive to prevent electrostatic failures, non conductive may be ordered. Available in -3 to -24 sizes. Only -3 is the same size as 2807/TFE and its imitators. Use standard fittings in -3, -4 requires different sleeve, so assembly has different part no, -6 and up have different fittings.

Fittings are also available with aluminium nipple (main body) and stainless socket and sleeve in - 4 and above.

Moquip TFE hose
TFE hose with stainless steel outer braid has many industrial uses and is manufactured as such in the UK and is compatible with Aeroquip and Moquip fittings, we offer such a hose because of its extremely competitive price and suitability for competition vehicle use. Available in all sizes -2 to -8 from stock. We can offer a PVC skin for this hose for added protection and easy wipe cleaning, available clear or coloured, -3 ex stock in clear. Skin must be cut back to take fitting

Fittings for 2807/ TFE racing hose, 666 and Moquip TFE hoses
The fittings are available in swaged or reusable form. Reusable fittings can be assembled using a vice and suitable spanner, use up to 3 times before replacing sleeve. Assemblies with swaged on fittings show a considerable price saving, most of the reusable fittings are available in swaged form, we will be happy to quote for complete assemblies.

Reusable fittings are three piece fittings consisting of a nipple (the main part), sleeve (olive) and socket (nut). Aeroquip manufacture a large range of "Super Gem" female fittings in mild steel, stainless steel and aluminium with stainless socket, the latter for 666 hose, but can be used on other -4 hoses by changing the sleeve.

There is a demand for specialised fittings not covered by the Aeroquip range, which are manufactured by us on our state of the art CNC machinery and supplied complete with the relevant Aeroquip sleeve and socket, we call these Moquip fittings. Fittings are usually mild steel, cadmium plated, but can be chrome plated. Stainless steel fittings can be supplied.

Last Revised: 16 November, 2001 . Copyright Think Automotive

[Robbie693]

Thanks Gerry,

Do you remember what size fitting you needed for the tank and size of hose you used?

[gerrym]

Robbie, I used -8 hose swivels to create a female JIC fitting on the two tank connections. Hopefully the attached photos explain. The 2nd photo is of a disassembled hose swivel end. (the brass tail was cut off and bored out to suit tank stub)
Regards
Gerry

[Robbie693]

I see now Gerry - thankyou.

Last question; did you have to remove the rear screen to put the new hoses in or can it be managed by attaching the new hoses to the old ones and pulling them through?