This is the pipe that connects to the master cylinders under the bonnet and the oil feed down by the high pressure filter behind the rear wheel. I had this pipe made up to bleed the brakes as per the workshop manual instructions.
If you suffer from spongey brakes you need this pipe to bleed the brakes properly. Suitable for all 74 series massey tractors, maybe suitable for 76 and 77 models but not sure.