Make a Locking TR7 petrol cap (140mm)
Posted: Sun Mar 15, 2009 5:14 pmI didn't like the aston cap that came with my Mk2 Midas so I decided to go back to the TR7 type. The problem I found was that these are now hard to find and that locking caps only seem to be available in the later 90mm size.
I bought a secondhand early TR7 cap from eBay for £5, when it arrived the retaining mechanism is wrong for the mini fuel neck, plus the seal was perished. I then bought a new old stock 2 lug metro fuel cap for £2 again from eBay (there are 3 lug types so beware).
First step was to remove the internal retaining mechanism from the TR7 cap (little cross-head screws), then using a dremel with a suitable bit grind away the plastic reinforcement until it was flush to the diameter of the metro cap. A 16mm hole was also drilled in the centre for the lock:
Next stage was to unclip the cover from the metro cap and then grind any lips flush, again with the dremel:
The Metro cap was then stuck to the TR7 cap cover using Tiger Seal. Any PU adhesive will do as it is unaffected by fuel (and is really strong). I made sure not to block up the breather or gum up the lock:
I gave it a day or so to dry and then fitted it to the car, I'm happy with the result and it cost less than £10 to do.
I bought a secondhand early TR7 cap from eBay for £5, when it arrived the retaining mechanism is wrong for the mini fuel neck, plus the seal was perished. I then bought a new old stock 2 lug metro fuel cap for £2 again from eBay (there are 3 lug types so beware).
First step was to remove the internal retaining mechanism from the TR7 cap (little cross-head screws), then using a dremel with a suitable bit grind away the plastic reinforcement until it was flush to the diameter of the metro cap. A 16mm hole was also drilled in the centre for the lock:
Next stage was to unclip the cover from the metro cap and then grind any lips flush, again with the dremel:
The Metro cap was then stuck to the TR7 cap cover using Tiger Seal. Any PU adhesive will do as it is unaffected by fuel (and is really strong). I made sure not to block up the breather or gum up the lock:
I gave it a day or so to dry and then fitted it to the car, I'm happy with the result and it cost less than £10 to do.