right.,..you need a vice; a sharp knife, 3mm allen key, 5mm allen key, 4mm allen key, lube of some sort, some rubber, 8mm spanner Remove the damaged crossover from the brake with an 8mm spanner. No cut the barbs out of the plastic hosing. Measure the old crossover and cut it with a sharp knife to ensure a clean cut. Now clamp the hosing in s avice eith the rubber around it to avoid crushing the pipe. leave around 1.5cm of pipe showing out of the vice. Now put a drop / dab of lube on the barb ( i use washing up liquid ) and proceed to tap it gently into the clamped hosing. repeat for the other side. Now refit the crossover....wind out the tpa ( bolt sticking out of the blade that pokes the piston ) and take out both bleed bolts. Now ... Either use a syringe and some mineral oil ( either royal blood or citroen clutch fluid )......in this case attach the syringe and pipe to the master cylinder wioth the use of another barb and a apiece of pipe or do a bath bleed.......immerse the whole brake int he bath ensuring the bleed bolts are under water. Now, cover the bleed bolt at the lever, pump the lever, release and then at the same time release your finger off the bleed hole.....repeat around 40 times to ensure a good bleed. Now; refit both bleed bolts and thighten them. Note; as your asking how to bleed your brake i can assume you've got an oil bleed int here.....in which case if you wnat to bleed with water you should first remove as much oil as possible from the syetm ( i personally run a tap therough the sytem )