This procedure is for changing the fluid in the main DSB launch system without the
need to re-bleed the cylinders or the system. It is more wasteful of fluid than draining
the whole system down but is more efficient in time. This method will not remove all
traces of the fluid but will make sure that any old fluid left in the system is mixed with
the new fluid. The procedure assumes that the fluids are completely miscible and
Deploy the launch vehicle, Extend the articulator for fitting launch beams remove the
final stop pin. Crane a launch beam, connect it to, and pin it to the forward launch
beam. Make sure that the crane is in a position so it that it can remove the launch
Drain the vehicle hydraulic tank using the drain procedure for the PLS vehicle.
Remove the cover on top of the main hydraulic return line filter, remove the filter
complete, replace the cover, and tighten.
Remove the hydraulic return pipe, the larger of the two pointing to the rear of the
vehicle, from the top of the oil tank. Cover both the open ends with plastic bags and
tape to prevent the entry of dirt and the loss of oil.
Remove the rear engine cover and place to one side.
Remove the tywraps and clip from the pipe and feed it back through the engine
compartment, being careful not to damage the end fitting. It may be necessary to
remove the spare wheel to get to the pipe clip.
Place the open end of the pipe over the right hand side of the vehicle into a suitable
container or drum to collect the old oil for disposal. MAN A should be stationed here
to operate the E-stop button to prevent overfilling and to allow him to put the hose
into another container or drum.
Fill the hydraulic oil tank with new oil using a pump with an in-line filter to ensure that
the system is clean. DO NOT POUR OIL DIRECTLY FROM THE DRUM INTO
Position MAN B to keep the tank topped up using the vehicle low warning as a
guide. DO NOT OVERFILL THE HYDRAULIC TANK.
MAN A should be prepared for either the old oil drum overfilling or the interface
cabinet control LOW LEVEL indicator illuminating and then must operate the
Emergency stop button on the interface enclosure to prevent air being sucked into
the hydraulic pump.
MAN B should keep the oil tank between minimum and half full at all times.
MAN C should now carry out the following build sequence in order to exchange the