Badly corroded petrol tank straps

[alextangent]

I've started my mini-rebuild, and I'm glad I started with the rear to get at the chassis tubes there, because my petrol tank is leaking 😳 from the sender. I'll get a new gasket and hylomar (I found the BC threads on this). None of this then

 

Now for lots of 🤔 🤔

 

I've undone the tank straps, but they look pretty corroded, and before I yank the tank out past them, which I'm sure is going to fracture them, I'd like to know if they're replaceable? How are they secured under the tank? Pop rivets? Are they easy to obtain? Plus there's been some corrosion of the tank were the straps have been touching the ali, but it doesn't look like its holed. But -- if it is, can I get away with using something like metalastic, or is it a new tank job?

 

Alex McDonald

A loud 1700 SS

[Graham Perry]

if I remember correctly they are welded at one end to the frame the tank sits in. You will need to make some new ones and pop rivet them in place as suggested. just make sure if you do pop rivet something in place that the compressed end of the rivet doesn't rub against the tank.

[Molecular--Bob]

Are your straps the round the tank ones that bolt together to fasten? If so they are pretty flexible. I just Por15'd mine The ones on my 1990 chassis had stick on foam strip on the tank and in the mounting cradle to protect it, it looked to be original, so maybe yours got removed at some point?

[alextangent]

The foam strips have disintegrated, but the tank's OK if a bit pitted in places (I even polished it ). The sender has a cork jobbie, disintegrated as well. Straps look solid enough, so I'll just paint as suggested.

 

Alex McDonald

A loud 1700 SS

[Graham Perry]

I know you have polished it, but I would be tempted to put some waxoil or similar onto the tank where the pitting occurred.

[alextangent]

I'm going to cover the bearing struts where the tank sits and the straps with some rubber sheet to isolate the tank fully from the other metal work. Waxoyl and the job's a good 'un. Cheers

 

Alex McDonald

A loud 1700 SS

[JACK FLASH]

This topic has started me thinking about the position the and mounting method of the tank. The method of 2 tank strap seems outdated to me. Has anyone ever used a better mounting system ?

 

When looking at the underside of the car, I started thinking and worrying abiut the fact that the underside of the tank sits completely unprotected. My Twin Cam has got a 1987 Ford LA chassis. Has anyone ever tried to put a protective plate under the tank or isn' t this necessary ?

 

Jack Flash

[alextangent]

I had the same thought. In fact, two thin long bolts from the lower rear chassis member (1ft long or thereabouts) and a V shaped piece across the top rear of the tank would secure it much better. I think later cars may have this; there are parts to do it on CC's website.

 

As to protecting the bottom of the tank, there's only support at two sides, so you'd need to fix something to the tubes front and rear if you didn't want it to flex. Again, CC have ali crushable panels for this, so it might be a later mod?

 

I'm going to use the tank strap method, but on the bottom and back of the tank stick a cheap cut up rubber mat, pimple/ribbed side to tank. Better than nothing.

 

Alex McDonald

A loud 1700 SS in bits

[JACK FLASH]

Alex,

 

Could you keep us informed about the progress of your mini-rebuild because I have a certain feeling that I am going to encounter the same problems within a couple of months. My garage has a certain suspicious smell !

 

Anyway, when I have time tomorrow I' ll take out the wooden floor (again) to have a look at the tank. Wouldn' t it be better to leave the floor out of the car ?

 

Jack Flash

[alextangent]

If you can smell petrol in the garage, make sure that you don't have a leak elsewhere as well. I had a carb fire about a month ago, caused by a dripping carb. 😳 Scary. Leaving the floor out won't stop the leak!

 

As to the tank, there's really only a few places it will corrode. Left and right bottom side on the supporting rail, tank sender gasket, straps. btw, I drove as far as I dared to empty the tank; it was reading nearly zero, but still had two gallons left to empty out when I removed it.

 

Editted to add; of course I'll keep you informed -- because every job I'm doing I need advice on 😬 😬 😬 from folks here.

 

Alex McDonald

A loud 1700 SS in bits

 

Edited by - alextangent on 24 Nov 2007 21:28:46

[JACK FLASH]

Alex,

 

I am quite sure that I haven' t got a leak in the fuel circuit because almost everything is new or had a rebuild at the beginning of this year.

 

The only part I didn' t tackle is the fuel tank, so the smell must be coming from there. I noticed that when fuelling up the smell in the boot of the car gets stronger, so somewhere fuel vapour is escaping over there. I suspect the connection between the fuel filler and tank or the fuel sender unit (gasket), which is on the top of the tank.

 

By the way, I took out the floor and I didn' t see anything that resembles a foam strip. The metal straps make direct contact with the tank, so I think this is far from ideal.

 

Jack Flash

 

[Sheds Moderator]

Jack, you *should* have a rubbery foam strip between the strap and the tank. If you haven't then it's been left out during the rebuild. I'd use something like a cut up inner tube if nothing else was to hand.