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Petrol Tank leak blues!

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Petrol Tank leak blues!

Posted by nicholas_clarke at October 30. 2018

Why is it that just when you think you have got a Lightweight nicely fettled something new crops up!   My Navigator's petrol tank has suddenly started weeping from somewhere on the back lower seam that the mounting bolt bracket is welded to.   I am pretty certain it hasn't rusted through from the inside because there is never any rust deposit in the fuel filter and a visual inspection suggests the inside of the tank is in good condition as is the outside which is still in it's original paint and doesn't show any signs of paint damage from rusting through.   Although I can't find exactly where I suspect there is a fatigue crack somewhere on the welded seam.    My quandary is do I try a slosh sealant like Tapox advertised in the NOC shop, or try and find a specialist who can find the leak and do a weld repair?    If I do use a slosh sealant and it doesn't work is there a way of removing it so that a weld repair can be done?   The only other solution is finding a decent second hand tank but that is both difficult and I suspect mighty expensive!   Any suggestions or advice gratefully received!

Nick

Re: Petrol Tank leak blues!

Posted by christopher_winsby at October 30. 2018

A leaking tank can result in a fire , makes the cost of a proper repair or getting a new one (even if you get an Indian made one and then have it fettled and painted) seem a bargain.

I would take it to someone who is recomended and not try putting a liner in it, cracks tend to get bigger and rust does not stop unless treated.

Attachments

Re: Petrol Tank leak blues!

Posted by mikael_ridderstad at October 30. 2018

When I thought I had completed a Manx restauration and filled petrol to start it, I found the tank leaking. Didn't like the idea of a potential fire. It is not uncommon with fuel tanks cracking due to vibrations. To find the crack I used compressed air at just slight pressure. Using leak finder (soap water works too) the crack was easy to locate. Opened the cap and continued a small flow of compressed air for two days to let remaining petrol evaporate. Meticulous cleaning of the surroundings of the crack to minimize risk for pores.  Then had a good welder fixing it.

Re: Petrol Tank leak blues!

Posted by nicholas_clarke at October 31. 2018

Thanks chaps, all wise words - its a real shame because the bike has never been restored and has a lovely patina which is going to be spoilt once I have repaired the tank because it will have to be resprayed.   Tracking down a good welder willing to take the job on will be a challenge I suspect and you never know what horrors you will find when you start welding a 54 year old petrol tank!    I had a look on ebay and see new Indian made Lightweight tanks are available from a vendor called Shopperstop-25 for £225 - does anyone have experience of their quality and accuracy of fit of the badges and on the bike?

Nick

Re: Petrol Tank leak blues!

Posted by patrick_mullen at October 31. 2018

Hello Nick,

Have you a radiator repair specialist somewhere local to you ?  If so go and see them.  They are usually experts at soldering/welding and already have the leak detection equipment required.

Patrick

Re: Petrol Tank leak blues!

Posted by mikael_ridderstad at October 31. 2018

On leak finding, a VERY small amount of overpressure is needed as air leaks much better than a fluid. If the crack is close to a bracket, welding is needed. On less stressed parts of the tank, tin soldering might suffice. A tinsolder on my Venom has not failed for more than a decade. I've also seen a tank where a  blob of polyester or maybe epoxi on the outside kept the tank leakfree for more than twenty years. Don't recommend that.

Mike

Re: Petrol Tank leak blues!

Posted by nicholas_clarke at October 31. 2018

I'm pretty sure the leak is where the rear mounting bracket is welded to the rear bottom seam of the tank Mikael so probably a welding job for strength.  Thanks for the suggestion of a radiator repair specialist Patrick - I hadn't considered that but they might be the right place to do the job - I will do some research.  Anyone know a petrol tank repair specialist / good quality welder in South Somerset / North Dorset area?   Any feed back on the quality and fit of new replacement tanks from India?

Re: Petrol Tank leak blues!

Posted by peter_holland1 at October 31. 2018

Nick,

If you have the correct rubber washers, cupped washer, and bolt for securing the tank then the tank is rubber mounted at the rear.The special tank securing screw and washers are also used on Featherbed frame, I believe. I've seen them on the NOC spares site.

If the rear tab on the tank is bolted directly to the metal tank mount of the frame, your tank will be subjected to more strain and more vibration. Commonly seen on lightweights. Make sure you have rubbers on the top frame rails too.

I'm sure the best solution for you will be to get the tank welded and restore the rubber mounting if necessary.

Peter

Re: Petrol Tank leak blues!

Posted by dan_field at October 31. 2018

If you get stuck tanks come up fairly often and aren’t very expensive.

dan

Re: Petrol Tank leak blues!

Posted by nicholas_clarke at November 01. 2018

Peter, frustratingly I replaced all the rubber mounts when I first got the bike and keep an eye on their condition because I know how prone to vibration fatigue they are - I suspect it is just the inevitable toll of 54 years hard work!

Dan, wise words having just been quoted £225 for the welding repair and another £275 for the tank to be rust treated and then 'lined' with Tapol by a specialist...….and that is without painting!!!   I'm obviously in the wrong line of business!

Anyone got an undented, un-leaking tank they want to  move on?

Nick

Re: Petrol Tank leak blues!

Posted by patrick_mullen at November 01. 2018

Those figures sound grossly inflated; obviously the person concerned didn't want the job and deliberately quoted you a figure which he knew was ridiculous.  Most people are very cautious about welding a fuel tank because of the risk of an explosion from petrol fumes so the tank needs to be well purged first. The actual job itself shouldn't take more than 15/20 minutes.

I have only ever welded one petrol tank; on a Honda VFR400 and that worked perfectly but I do admit that I wasn't too keen on doing it. I think I filled the tank with water before welding on the advice of an expert welder.

 

 

Re: Petrol Tank leak blues!

Posted by nicholas_clarke at November 01. 2018

The chap I was speaking to is a specialist classic motorbike petrol tank repairer Patrick - that is all he does so he was keen to have my business.   I think he is used to dealing with wealthy owners of Brough Superiors and Vincents who wouldn't flinch at that sort of cost rather than humble Navigator owners!   I share your concern over welding a petrol tank even when it is well purged - not for the feint hearted!   Your solution seems very sensible....

Nick

Re: Petrol Tank leak blues!

Posted by john_holmes at November 02. 2018

I will post the company tomorrow, I got a Triumph tank undented, pressure tested, leaks welded, badge holes relocated and tank top rack inserts added for £110 a few years ago. Very pleased with the result.

Re: Petrol Tank leak blues!

Posted by mikael_ridderstad at November 02. 2018

If you use water to get rid of remaining petrol, it is extremely important that the tank is completely dry before welding.

Re: Petrol Tank leak blues!

Posted by john_day at November 02. 2018

run exhaust gases through the tank for 10 minutes, the heat and the fumes purge any petrol fumes

Re: Petrol Tank leak blues!

Posted by nicholas_clarke at November 03. 2018

Previously john_holmes wrote:

I will post the company tomorrow, I got a Triumph tank undented, pressure tested, leaks welded, badge holes relocated and tank top rack inserts added for £110 a few years ago. Very pleased with the result.

John, many thanks - I am getting ridiculous quotes so far with £225 just to sort the leak!

Nick

Re: Petrol Tank leak blues!

Posted by nicholas_clarke at November 03. 2018

Mikael & John, thanks for the top tips - I am exploring all options to see what the most cost effective long term solution is.  Safe welding is a fundamental!

Re: Petrol Tank leak blues!

Posted by dan_field at November 03. 2018

They come up on eBay fairly regularly, for about 40-60 quid, and the club has a couple for half that.  There has been a painted one on eBay for silly money but that seems to gone for the moment.

Dan

Re: Petrol Tank leak blues!

Posted by nicholas_clarke at November 03. 2018

Thanks Dan, with winter looming I am going to take the bike off the road and keep an eye on ebay and the club shop to see if a decent one comes up.   I am also shopping round for a good welder who is happy to repair my tank at a sensible price - apart from the leak it is dent free and in good condition.   I am also in a dichotomy - repairing the tank will mean a re-spray which will look out of place with the original oil tank, battery box and mudguards which are in their original but patinated paint.  Should I bite the bullet and have them all resprayed so they match - and will be more cost effective in the long run!???   Perhaps I can get the job past financial scrutiny as 'an early Christmas and birthday present'!

Re: Petrol Tank leak blues!

Posted by patrick_mullen at November 03. 2018

Hello Nick,

Tanks also turn up at auto jumbles and don't normally fetch very much money but it is a bit pot luck how good they are.  I got one at Stafford a couple of years ago for £10 and it turned out to be much better than it first looked; no dents and no leaks but the most horrid paint you have ever seen.

Your original paint from the sixties was cellulose based so really if you intend to use the bike (other than just to the occasional show) then a respray in 2K would be a better option. Matching the colour shouldn't be a problem - just take a sample item such as the tool box lid to the paintman" at your local motor factors.  The painting itself is a bit of a pfaff as you have to do a first base coat in silver before actually spraying on the blue colour base coat, then finish off with 2K lacquer which is petrol resistant .

If you live near a country area you could call with the local agricultural workshop and ask them about repairing the tank.  These people are usually the old fashioned mechanic/engineers who can do anything- fix tractors/weld gates/make trailers;  they normally also have very good up to date equipment such as tig welders/lathes etc. and are used to fixing all sorts of odd things for the farmers.

Patrick

 

Re: Petrol Tank leak blues!

Posted by dan_field at November 03. 2018

There’s a tank on eBay at the moment, not that it looks very good though! Also some styling panels and delux panels and a nice looking Nav in red.

Re: Petrol Tank leak blues!

Posted by nicholas_clarke at November 03. 2018

The tank on ebay has certainly seen better days Dan but the red Navigator looks cracking - shame about the asking price of £3895 which probably explains why it has been on there for so long!

Re: Petrol Tank leak blues!

Posted by john_holmes at November 03. 2018

This is the tank repair company I used.

 

Www.cwclassic.co.uk

Re: Petrol Tank leak blues!

Posted by nicholas_clarke at November 04. 2018

Previously john_holmes wrote:

This is the tank repair company I used.

 

Www.cwclassic.co.uk

Thanks John, I will give them a call on Monday and see what they quote!

Nick

Re: Petrol Tank leak blues!

Posted by john_holmes at November 04. 2018

I sent them lots of pics and then they sent me an estimated price, this was the price they charged after the work was completed.

Re: Petrol Tank leak blues!

Posted by dennis_thompson at November 04. 2018

Nick, I may have missed something but the NOC shops shows at least three petrol tanks for sale for 'Lightweights' all around the £25 mark. I paid £65 for mine off eBay plus £15 postage so the ones in the NOC shop sound like a bargain. They are showing as 'in-stock'.

Dennis

Re: Petrol Tank leak blues!

Posted by graham_squires at November 04. 2018

Previously Nick Clarke wrote:

Thanks chaps, all wise words - its a real shame because the bike has never been restored and has a lovely patina which is going to be spoilt once I have repaired the tank because it will have to be resprayed.   Tracking down a good welder willing to take the job on will be a challenge I suspect and you never know what horrors you will find when you start welding a 54 year old petrol tank!    I had a look on ebay and see new Indian made Lightweight tanks are available from a vendor called Shopperstop-25 for £225 - does anyone have experience of their quality and accuracy of fit of the badges and on the bike?

Nick

If I had a tank and side panels with original paint and patina , I would take them off the bike and put them in cotton wool because they would be irreplacable and could always be put back. I would then source spares to replace, and paint however looked good to my taste and not worry too much about originality as the originals are in cotton wool. A simple solution to a leaking tank is there , it just needs careful thought.

GRAHAM

Re: Petrol Tank leak blues!

Posted by patrick_mullen at November 04. 2018

No bids up to now on the Ebay tank - it does say £10 or best offer - and it appears to have both cap and badges.  The badges should be worth that,  so it should be worth an enquiry at least if anyone is near Ipswich who could collect and save the £20 pound odd postage cost.

The same advertiser also has other Jubilee stuff but a lot of it appears to be totally incorrect and effectively just junk. He also has a pretty poor rating.

 

 

Re: Petrol Tank leak blues!

Posted by dan_field at November 04. 2018

I sent him an email about the battery  and tool box, politely suggesting it wasn’t from a jubilee, he replied saying “that’s what they came  off”  so he obviously knows best!

Re: Petrol Tank leak blues!

Posted by patrick_mullen at November 05. 2018

Yes I have to agree with that.  He had a "Jubilee" headlight a few weeks ago - I think for £10-which was obviously not from a Jubilee but someone probably got a bargain as the speedo was a Smiths 120mph chronometric which looked all there.

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