Squat Switch replacement procedure

[MWGu3]

on my 1978 R182RG I have been experiencing an intermittent voltage spike after I rotate and it goes away once I land. We have investigated several possibilities and have found some degradation of the wires connecting the squat switch on the nose wheel. It makes sense that the voltage spike appears when the nose wheel extends after weight is removed and goes away once the weight is back on the gear. My question for the group is, has anyone ever replaced one of these switches and do you have a procedure to do so? If so, do you have any words of wisdom to share. I have the new part in hand.

Thank you,
Matt
N9053C

[scottrsellers]

Hi Matt,
As the wiring ages and insulation ages/cracks every retract cycle that bends or stretches the wires could be your cause of voltage spikes. Bad wiring wouldn’t necessarily mean a bad squat switch.
Troubleshooting of wiring while cycling the gear on jacks may be in order. We also spray our squat switch with electronic cleaner to remove dirt in the switch that also makes sense to do while cycling the gear on jacks.
Will look into a troubleshooting procedure and reply. Mike Pattison had the same thing on his R182 and the issue was a dirty squat switch.

[scottrsellers]

Forwarded your question to R182 landing gear expert Paul New. His reply:

There are a few problems with the person's description of the problem. First, the squat switch and its wiring won't be the cause of the intermittent voltage spikes. Second, any written procedure for parts replacement is detailed in the service manual and is where anyone performing maintenance should start. (See Section 5 of the R182 Service Manual, p.60A for NLG troubleshooting viewtopic.php?t=14)

Last, I seriously doubt the voltage spikes are happening all the while the plane is flying. My guess is that it happens anytime the gear motor cycles. It would be much easier to troubleshoot with a bit more detail from the person that is experiencing the problem. Details like, exactly how often does the spike occur, does the pump run when this happens, does the alternator kick off line, etc.

Matt- Please advise on the above questions.

[MWGu3]

Thank you for the replies, my learning curve is pretty steep as this is my first airplane. I found the procedure in the service manual for replacing this switch, although we have cleaned up and insulated the wiring issues we found and the switch is clean. Through further reading and investigation, we are also looking at the power pack. Initial indication is it is low on hydraulic fluid and the voltage spikes may be from the pump trying to run and not getting the desired pressure, the POH was helpful in pointing in this direction. Does anyone have a good way to fill the hydraulic fluid reservoir without becoming a contortionist?

For Paul New, I have a video of the spike sequence, it is every 4 seconds, I was unable to tell if the gear motor was trying to run or not. I would be happy to forward the video, not sure if I can post it here. The voltage meter goes from normal of needle width right of center, to full discharge, to full charge, back to normal every 4 seconds.

Thank you,
Matt

[scottrsellers]

Matt - We carry a small quantity of 5606 hydraulic fluid in a container that can be added to a small hand pump per the below pics. Checking hydraulic fluid level is a preflight item worth adding to your checklist. Carrying the fluid can be messy/smelly so we use multiple Ziplocks for best results.
Forwarded your other questions to Paul New and will post his reply.