Landing gear power pack problem

[Will W]

My 1978 182 RG had a landing gear problem out of the clear blue this week, when the gear failed to extend fully when the gear selector was placed in the DOWN position on approach to landing, causing the warning horn to sound as I reduced power. Executing a go around, the gear would not come up either. Attempting to pump the gear down manually was not successful. I reset the circuit breaker with the gear selector in the DOWN position and the gear did go down with a green light showing . . . much to my relief. I flew gear down to the shop where they were able to diagnose the problem, and the circuit breaker popped going either up or down. Replacing the circuit breaker did not solve the problem. They advise the power pack be replaced with an overhauled exchange for $7,250.

Anyone else had a similar experience?

[scottrsellers]

Will - Below is my reply from the CPA forum posted for others to see. A further comment would be to check the hydraulic fluid reservoir for quantity, and the system overall for leaks. We recently had a similar issue related to insufficient quantity of 5606 fluid making the pump intermittent- was partially pumping air.
We'll look into this further and advise.

"Some trouble shooting may be in order to ID the problem prior to pump replacement. There’s a Troubleshooting portion in the Service Manual in Landing Gear Section 5, 5-3 where Trouble items include ‘Landing Gear Fails to Extend’, with another Trouble item as ‘Gear Does Not Fully Retract, but Pump Motor Continues to Run’ with a 11 Remedies listed. Just one of those is pump replacement. Since your pump ran with the breaker in this could be an pump circuit problem where the listed remedy is Check Ground, Repair or Replace Wire and others."

[scottrsellers]

Will - I forwarded your question to Paul New who replied as follows:

Ugh! It's almost certainly not the powerpack. That's the standard response from mechanics that don't want to spend any time troubleshooting the actual cause.
The circuit breaker trips because the pump motor is bad or the pump run continuously. The pump runs continuously because the reservoir is low or the pressure switch doesn't open. If the shop can't explain what troubleshooting they did to isolate the problem to the power pack then I suggest running away and find a better shop.

[scottrsellers]

For reference Service Manual Section 5, Landing Gear, Brakes and Hydraulic System and the Troubleshooting Landing Gear Retraction System list is viewtopic.php?t=169 also posted separately in this R/TR182 Gear System portion of the site.