This just *can't* be good. The retract cylinders have always "popped a spot", but the nose gear is really bad now. I guess it's time to take these puppies off and have them rebuilt. Any of you done that, and if so, can you direct me to a set of directions to accomplish that, and who does a good job on rebuilding them. Maybe it's better to just buy new cylinders?

Scotty,

 

To me, it looks like the leaks are in the connectors/tubing even though the door actuator spring looks pretty wet also.  Once the gear door is open on approach it is hard to tell where a small leak is from because of the swirling air.

 

Were I you, I would put the craft up on jacks, remove the door, clean everything up with Stoddard fluid (mineral spirits), pressurize the system (up and/or down and try to determine where the leak is from.

 

Are you also getting frequent burps from the pump (up or down)?  This can mean a piston o-ring gone bad (there are other possibilities).

 

If it is the door actuator, order a rebuild kit from Aero-Crafters and remove the cylinder from the airplane.  Note that door actuators are easier to rebuild than gear actuators because you do not have to remove the fittings in these wee actuators.  You will note that there is a hole in the actuator shaft that allows you put a pin thru it to hold it from turning while you loosen the rod-end locking nut.  Remember to count the number of turns when the rod end is removed so reassembly should give you the correct length.  You will need good snap-ring pliers to remove the front shaft retainer.  Note carefully the orientation of the shaft seal (usually trapezoidal in shape so that the internal pressure forces the seal against the shaft).  You will probably notice blackened fluid at each end of the unit - this is from o-ring wear and note that some fluid never seems to leave the cylinder.

 

Once you remove the piston, everything should be kept clean.  You will probably need a pointed hook to help remove the piston seal.  Examine the cylinder walls for any scratches (these can be the cause of leak down).  Make sure everything is kept clean.  See if you can determine what cause the shaft seal failure.  Sometimes a piece of seal will flake off, sometimes dirt will be present, sometimes a scratch has developed on the shaft leading to a leak. Cylinder or shaft faults require you to replace the unit.

 

When you start putting the seals/o-rings back on make sure everything is lubricated with hydraulic fluid.  Keep everything clean.  Be very careful when re-inserting the piston back in the cylinder so that the cylinder wall is not scratched by a hard part of the piston.  Lubricate the cylinder and keep everything clean.

 

Gear actuators are similar, but the fitting(s) must be removed to allow the shaft carrier and end plug to be removed.  The recommended procedure for reassembly is to insert the shaft from the back end to avoid scratching the cylinder.  I have carefully done it from the front without damage.

 

If you need new cylinders, remember to put a little hydraulic fluid in each end before exercising the actuator - supposedly they come with some goop inside but exercising dry actuators has been known to cause problems.

 

Did I mention to keep everything clean....