read this post and mine to cover all the parts
http://http://www.dieseltruckresource.com/dev/repair-leaking-fuel-pin-t153154.html?t=153154
replacement kit BOSCH costs 12 €, you can ask in any shop bosch spare for VE pump
disconnect all the tubes that reach the top of the pump and remove the 4 allen screws holding the pump, important not to pull it yet, behind the round part , close to the firewall is there to remove the screw, squueze it under the pump
already have the pump outside, better cover the open area in the car and go to work at a desk, comfortable chair and reading lamp.
view of the pump
start removing the cap with an Allen wrench, the screws are very strong so tap it and unlock oil