On the rubber bumper cars that have the oil cooler located under the rad rather than in front of it- the location of the nuts holding the pipework are impossible to get at with an open ender spanner. The only other way I could see is to remove the cover below the oil cooler from under the car then slacken the oil cooler fixing bolts and drop the cooler to access and release the pipework unions – all under the car.
Didn’t fancy doing all that especially with a bad back that’s been playing up since i did another job under the car recently.
The union nut is 15/16" so i bought an old ring spanner off eBay cut it in half and cut a slot in the "ring" to sqeeze over the pipe and slide it along the pipe to the union nut.
Care must be taken not to put too much leverage on the cooler as it is only aluminium.
It worked well. I removed the pipes and re located them to a tidier route to the cooler. A job that I’ve been pondering for a while as the pipes had been coiled up behind the front grill with cable clips and looked a mess.
MGB tips mods and maintenance 
Nice modified tool – such innovation!
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