Break Fluid Reservoir Spilling?

Fuel Tank FoamCAVEAT / WARNING (25th June 2011): Since purhasing my own foam, I have been told from various sources that brake fluid may dissolve or break up the foam, which is not a good idea! As such I intend to place a small piece of foam into a jam jar and fill with brake fluid to test the theory. As such I cannot endorse this ‘Top Tip’ for the moment.

I heard a fantastic top tip yesterday that I wanted to share. On both cars I have suffered with break fluid spilling/leaking from the reservoir and onto the paintwork. The problem seems to be that there is not a coherent seal on the cap, no matter which you use. Over tighten and you run the risk of damaging the cap thread.

The resolution from Caterham was to go to a sports shop and tie a tennis style wrist sweatband with a cable tie around the cap to catch the leaking fluid. Granted yes this works and I have found any absorbent roll will do the same too.

However yesterday’s solution was to place a small cube of ‘fuel tank foam‘ into the reservoir. I was told that many Rally Cars use this trick. Wondering where I could obtain such a product, I have found Merlin Motorsport stock such an item for less than £1.20 and from their page:

“Effectively baffles fuel to control surging. Mitigates fuel spray in the event of fuel tank rupture from compressive forces. Explosion suppressant foam has been mandated by a number of world class organisations that sponsor professional and amateur automobile racing. Including the SCCA NASCAR and the FIA. 80mm cubes to allow you to fit to existing tanks”

The size of this cube is 8cm*8cm*8cm  which I assume I will need to cut down to 2cm*2cm*2cm or similar?

I will wait until I am down at Castle Combe on 7th June to buy as it’s going to cost an additional £4.44 to post. If anyone wants a chunk of my foam, please let me know. If anyone tries this before me, please let me know the outcome.