Hi all,
regarding above issue, i bought seal kit from pvdobson, uk and i repair it my self. I will not say it's very easy but if you are into mechanics you will be able to do it. will describe below the way to do it.
1.First you must remove the drum from the machine after you remove the 5 or 6 allen type bolts of 1/2" that hold the actuator on the machine body. Note that the one bolt is hidden right under the return oil line of drum.
2.Put the drum on a stable base (use 2 robust wooden blocks to support it and let the splined shaft extension between the blogs down under)
3. unscrew and remove the, i thing 10 bolts of the top cover. You will notice there are three bolts slots in a triangle pattern that will accept 1" screws. cut 3 pieces of 12 mm diam. and 7.5 cm length of metal rod and drop each one in the holes. Support the main central shaft in such a way that won't lift along with the top cover. Then screw the three bolts equally till the top cover lifted completely. At this point you can remove the steel ring (collar) of main shaft. Take a note that the rounded side is facing down. Then carefully remove the orifice plates and springs. Mark their position.
4. Make a cover out of sturdy wood exactly as being the top cover (dummy) and support it with 3 bolts and flat washers. you can use from the ones removed with the addition of spacers to cover the distance.
5. Turn the actuator upside down. Remove the bottom cover in the same way.
6. lift the main shaft very carefully. (it's heavy).
7. Unscrew the 8 bolts on the side of the rotor 1/2". Remove the 1/4" bolts as well. Under the 1/4" bolts there are steel shafts that connect the stopper on to the rotary body. Very carefully using a chisel of almost same diameter hit the steel shafts at a sequence from the middle and cross diagonally towards the two ends. This needs patience as this parts is there ever since the machinery was build.
Once removed replace the seal and supports. Make sure you lubricate well parts prior. Put this stopper back, using it's own bolts but using spacers. Tight them is a sequence will pull it back to it's position. Make sure you lubricate the steel shafts and slots and also the parts must be pulled back very straight, otherwise will lock.
8. replace main shaft seal and seal supports and put it back. Make sure that the shaft sits in the same position as when removed.
9. Replace the main seal on the actuator body and also the seal and scraper on the cover neck. Use a lot of hydraulic oil on all seals and shaft.
Lower the cover slowly and using three bolts to locate the screw slots let is rest with it's weight. Tight all main bolts of cover with hand strength , in a sequence as described before.
10. Turn the actuator upside down and follow the same process. (put orifices and springs in the same place removed). At this point i pour hydraulic oil in the empty space. This will give enough lubrication to the wals of actuator and also will need no time to remove air from the system when put back.
11. Using a pry bar and a tube i locket the actuator and i tight bolts to 200 lbf-ft
Now the part is ready to be put back
Now will try and attach some photos taken. Good luck to the ones will try this.