Fibreglass Petrol Tank Repair

snowdr · Nov 6, 2023

I have a 72 Interstate with a fibreglass tank, which has not given any ethanol related problems so far using 98 octane supermarket petrol here in France.
However, when replacing the tank recently I felt one of the rear mounting thread inserts turn slightly, and I now have a slight petrol seepage from it.
My thoughts about repair have been either to replace the bolt with a stud, inserted with JB Weld, or to abandon the rear mountig completely, and fill the hole with JB Weld. Is JB Weld suitable for this application? Has anyone any other ideas for repair?
I know a fibreglass tank is on borrowed time, but a new steel Interstate tank is not easy to source, without going through the apparent lottery of the ebay suppliers.
Thanks for your help.

concours · Nov 6, 2023

JBWeld is impervious to gasoline, including E10, I tested & verified it 12 years.

baz · Nov 6, 2023

snowdr said:
I have a 72 Interstate with a fibreglass tank, which has not given any ethanol related problems so far using 98 octane supermarket petrol here in France.
However, when replacing the tank recently I felt one of the rear mounting thread inserts turn slightly, and I now have a slight petrol seepage from it.
My thoughts about repair have been either to replace the bolt with a stud, inserted with JB Weld, or to abandon the rear mountig completely, and fill the hole with JB Weld. Is JB Weld suitable for this application? Has anyone any other ideas for repair?
I know a fibreglass tank is on borrowed time, but a new steel Interstate tank is not easy to source, without going through the apparent lottery of the ebay suppliers.
Thanks for your help.

https://www.ebay.co.uk/itm/12617185...gGXShiHQWK&var=&widget_ver=artemis&media=COPY not bad for money

marshg246 · Nov 6, 2023

baz said:
https://www.ebay.co.uk/itm/12617185...gGXShiHQWK&var=&widget_ver=artemis&media=COPY not bad for money

At least in the US, it's worth way more than he's asking and he'll take offers!

MexicoMike · Nov 6, 2023

Do the JB Weld repair; it will work fine. Use Standard JB Weld, not the quickset version.

cliffa · Nov 6, 2023

marshg246 said:
At least in the US, it's worth way more than he's asking and he'll take offers!

It looks as though he's not interested in posting it though

"I am not keen on posting the tank because of the danger of damage."

marshg246 · Nov 6, 2023

cliffa said:
It looks as though he's not interested in posting it though

"I am not keen on posting the tank because of the danger of damage."

And, he doesn't take PayPal. So, it sounds like you need to go to him.

snowdr · Nov 7, 2023

Thanks for the confirmation that JBWeld is suitable for the repair. That's the route I'll be taking.
The tank on ebay looks interesting, but the location would give me problems. As a matter of interest, are there any significant differences between fitment of mk3 and pre-mk3 tanks, or in clearance underneath?

Fibreglass Petrol Tank Repair

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