SERVICE MANUAL & ICA
WIPLINE 3730 & 3900 FLOATS
Page 26
Revision K
P/N 1002551
The landing gear is simple to remove, as there are only two pinion bolts, a drag link bolt and two brake lines
holding it in. To remove the retracting mechanism, disconnect the gear light wires in the inner gear well side
compartment and the two hydraulic lines. All that remains are twelve allen head cap screws which are easily
accessible from the compartment behind the gear well. Occasionally the RTV sealant around the cap screw holes
holds the actuator solid but is easily loosened when pried from the top.
5.3 REMOVAL OF MAIN GEAR AND RETRACTOR
If for any reason the main gear retractor must be disassembled or need replacement of the hydraulic cylinder, it
may be accomplished as follows:
With entire unit assembled except for the bolt securing the lower end of the retracting cylinder, put the drag brace
in the retracted position (against stops) with up lock hooked. We now set the travel of the cylinder by extending it
until it is bottomed and observing through the anchor bolt hole on its base and retractor body. The lock nut on the
ram should be loosened and the ram turned (thus adjusting total length) until it is about 1/32” too long. This will
allow the drag brace to bottom on its up stops before the hydraulic ram bottoms out when gear is retracted. Re-
tighten lock nut and install the cylinder bolt. There should be enough travel left on the other end to amply hook the
down lock—this can now be checked.
The next item to be adjusted is the up-lock release rod. When the gear is in the up position and starts down the
pivot should push against the release rod to raise the hook just high enough to let it snap over the bar (in the drag
brace) and need not be adjusted to raise so high as to miss the rod completely, as this can cause the pivot to hit
the rod while the gear is being retracted. Usually if a gear has been retracted while the aircraft was on the ground,
this rod will be bent because the pivot is in the wrong position (pull instead of push) when the drag brace comes
up.
With this done, the only thing left is to adjust the down micro switch (the up can be adjusted in the float) and this
is accomplished by bending the probe. On newer models this switch is a magnetic proximity type and is located
in the compartment behind the wheel well and can be adjusted after actuator installation. It can be noted that the
down lock hook contacts an aluminum spring containing the magnet and positions it near the bulkhead where the
proximity switch senses it through the bulkhead. It is a good idea to attach an ohmmeter to the switch to see that
it functions and use a hand hydraulic system to operate the unit as they have been known to “click” without an
actual contact or to “click” and get a contact and to lose it again when the hydraulic pressure is built up against
the lock. Before installing the unit, a dab of waterproof grease should be put on all contacting surfaces such as
lock hooks, pivot, etc.
5.4 ADJUSTMENT – MAIN GEAR
Installing the actuator is almost as simple as removing it. Before installing, a small dab of sealant such as RTV
silicone rubber or chromate paste should be applied around each hole on the mounting flange. The unit is then
inserted and held in place while a second person starts a couple of the allen head cap screws. The procedure is
then just the opposite of the removal. Be careful to draw up the pivot bolts on the main gear casting only lightly as
the tab can be easily broken or cracked. This also applies to oleo and drag link bolts.
5.5 INSERTION
