just something i came across playing with double acting mini pneumatic air cylinders .. i fit them with push fittings and run hard plastic air line between 2 cylinders of equal size .. then fill a jar with power steering fluid ( caution toxic ) put on some gloves and submerge 1 cylinder with lines ..work the cylinder till no more bubbles .. keeping this one submerged and lines ... put 2nd cylinder in jar and work bubbles out then making sure to know which line is which and have 1st cylinder closed and 2nd open .. connect free ends to 2nd cylinder so the lines go to the opposite end of the opposing cylinder .. remove and wash out side with dish soap ..or other mild degreaser .. and u have hydraulics.. ... .. they do take a bit of force to move so i would think high torque servos would be needed to move cylinder A in a hidden location on your rc so that cylinder b will function .. i would like to test this using other lighter weight oils and or hydraulic fluid types .. . i used the CDJ2B10-30-B 10mm 30mm Stainless Steel Double Acting Pneumatic Mini Air Cylinder's . and got 4 of them for under 11.00 shipped from china . usd these fittings M5 Male - 4mm Straight Push in Fitting Pneumatic Push to Connect P&T 4 pieces for 2.91 ( need 2 per cylinder ) . and 25 meters of 4mm air line PU hose for another 11.00 and for clevis u can use traxxas ball ends ..