As ABA Scirocco said, do not attempt to disassemble the fuel distributor as it has many springs and rubber washers inside of it. Plus I understand that the VW factory uses a special wax to seal the top and bottom sections of the unit.
Most likely the Control Plunger is stuck if you are not getting any fuel at the injectors. This condition happens when the fuel distributor is not used for a very long time, such as a year or longer. The residual in gas will cause the Control Plunger to stick in its bore.
The Control Plunger is machined exactly to its bore, and Control Plungers can not be interchanged with different fuel distributors.
Remove all injector lines and fuel hoses from the fuel distributor. Make a diagram of all connections if you have not previously performed this removal. Next remove the three screws that hold the fuel distributor to the top section of the air flow plastic housing. Carefully lift the fuel distributor and place your hand under it in the event the Control Plunger moves freely. However most likely, it is stuck in in its bore.
I have had success with soaking the entire fuel distributor in solvent (ie lacquer thinner, etc) for several days. Prior to soaking, I spray WD-40 in all of the ports. After soaking, I use compressed air to remove the Control Plunger. Place a rag under the bottom of the fuel distributor and blow air into the top center port (control pressure connection), hopefully causing the Control Plunger to move downward from its bore. Do not use pliers in an attempt to pull the Control Plunger out as pliers can cause marks on the plunger and damage it.
You may have to repeat the soaking process several times, depending on the amount of gas residual in the fuel distributor.
Some of the fuel distributors have four (4) metric allen caps next to each of the injector line ports. If you remove the caps, you will find small filters under the caps. These filters can be cleaned and re-installed. Beneath the filters are metric allen screws that are "factory-adjusted" for the amount of fuel flow from each injector port. Do not attempt to turn these metric allen screws as you will change the amount of fuel flow. I know this from prior experience!!
Once the Control Plunger is removed, clean it with spray carb cleaner, and spray carb cleaner into all of the ports. Then use compressed air to blow the entire unit dry. The Bentley says to put a light coat of fresh gas on the Control Plunger and reassemble the unit. Good luck, WWR.