emergency hand pump opertions

[cessnadriver]

Hello all. I used the the hand pump (w/the master-OFF) and opened the doors. Now I'm trying to raise the doors (w/master-ON). The hand pump is hard to pump. So someone told me to make sure the solenoid clicks when turning on the master----Its does! When I push the lever full down- I can get about 8-10 pumps on the hand pump BEFORE the pressure builds up and there is no movement of the doors. ANY ADVICE??

[Mich3773]

I recall I was told to never pump the gear up/doors closed. The model H has a placard "CAUTION DO NOT PUMP WITH GEAR UP SELECTED" and the pilot's manual calls the pump an "emergency extension hand pump". The service manual says that there were major design changes to the gear system in 1979, so maybe this doesn't apply to all models.

[cessnadriver]

Mich3773. Thanks for the reply. But my older (1965) doesn't have that restriction.
Regards, BILLS

[Ed Coffman]

Leave the selector in the down position and keep pumping. Did you read you POH?

[Jerry De Santis]

On my 1975 P337G plane, to operate landing gear doors, keep master switch in off position. Pull the manual landing gear handle outward (telescope design) and pump up and down until doors are fully open. To close the doors, tuck the telescope handle back in the closed positioned and turn it slightly to lock it Down. Once this is done, turn master switch on. The doors will retract quickly.

Jerry
N34EC

[Ed Coffman]

Jerry, you have the electromechanical hydralic pump. Master off, pump. gear doors open. Master on gear doors close. In earlier planes with mechanical hydraulic pumps


" OPERATION OF LANDING GEAR DOORS (AIRPLANE ON GROUND).
For inspection purposes, the landing gear doors may be opened and
closed while the airplane is on the ground with the engine stopped. Operate
the doors with the landing gear handle in the "down-neutral" position.
To open the doors, turn off the master switch and operate the hand pump
until the doors open. To close the doors, turn the master switch on and
operate the hand pump.
NOTE
The position of the master switch for gear door operation
is easily remembered by the following rule:
OPEN circuit = OPEN doors
CLOSED circuit = CLOSED doors

[cessnadriver]

Hello Ed.
YES I read my AFM and the maintenance manual, although I'm currently NOT a Skymaster driver I am a A&P and did due diligent. I'm asking because using the AFM reference to "Open circuit Open door and vice versa", my C337 will NOT close the doors using the emergency pump. I have checked the wiring/limit switches and they are fine. I did verify the "Clicking of the solenoid" when the master switch is turned on, as suggested by several members. Doing more research, I may have found a possible solution. Near the end of servicing the power pack I see there is a procedure of "bleeding the time delay valve" by running the front engine (1965 model) and holding the gear lever down for one minute (Para 5-244). I'm trying this procedure this morning, wish me luck.
Thanks, BILLS

[Cloud9sa]

Try the same thing with the master switch on prior to starting the sequence for gear down. Don't know exactly why, but in our experience, the doors with close when hand pumping, and will not close if the master is off.

[cessnadriver]

Tracy. It looks like you have a newer C337 and that it probably has a electric/hydraulic system where mine is engine driven hydraulic pump. Anyway the systems are set-up so any time you loose electric power the solenoid is in the position to allow you to hand pump the gear down. That's why you cannot pump the gear doors closed WITHOUT the master switch, the solenoid in the system is thinking there is no electrical power and wants to put the gear down. I hope this explanation helps. Believe me I've gone through this during my annual and now understand the system much better.
Regards, BILLS

[Learjetter]

Hi guys- just FYI in case you're similarly afflicted.

I got tired of watching helplessly as screws and washers and who-knows-what went disappearing down under the emergency hydraulic hand pump with it's nearly shredded-to-pieces rubber gasket skirt (P/N 1280119-1, 1977 NA G model).

I went to the local fabric store and got some rubberized fire-and chemical- resistant leather-type fabric and fabricated a new skirt under "owner-produced" guidance in AC 20-62E and installed it with pilot-signed logbook entry as preventive maintenance under 14 CFR 43 Appendix A.

The skirt itself is just a wedge-shaped piece with two pieces of elastic sewn in--one inside the opening collar under rolled-over hem, and the other on the "top" of the skirt to allow stretching w/o bunching. It's held in place with a sandwich of felt gasket material cut to oval shapes.

Total cost? about $14 in 1 yard of fabric & some gasket material and 3 hours fabricating time.

Inflight Ops Check -- good.

[mshac]

Nice job LearJetter, but I'm not surprised you didn't want to buy Cessna's $388 replacement rubber boot! I looked on Summitracing.com, and they have 100's of rubber shift boots to choose from, mostly from $15-$30 each. I bet you could find one there that would fit.

[wslade2]

I thought I read somewhere in the forum about McFarlane making these?

[hharney]

Bill

Is the gear working correctly or are you trying to toubleshoot something? The operation you describe above should work unless there is a switch somewhere not closing that allows the valve to shift. Leave the doors open and when you fire up the engine just cycle the gear handle down and the doors should close. Not sure why they wouldn't with the hand pump

[cessnadriver]

Thank you! I'll try that first thing tomorrow. And no I'm not troubleshooting anything I just want the doors closed so I can start my CLT multi engine training. Not that you are suggesting a flight. I was advised NOT to try a take-off with the doors open, increase in drag, in case I loose the front engine (with the hydraulic pump). As for why the hand pump isn't working, NOT sure, I hear the solenoid click when I turn on the master switch. But every time I try to close the doors with the hand pump the pump pressurizes the system and acts like it's trying to open the doors instead of closing them?? Then afterwards if I switch the gear lever, from full down to neutral down the pressure is released and I hear a loud clunk somewhere near the front doors. Thanks again for the advice.
BILLS

[hharney]

Bill

Just to be sure, when in static condition and operating the gear doors you DO NOT select the landing gear handle, just pump the E handle. Just making sure you were not also selecting the gear handle......