Does anyone have experience replacing the master switch (piano key style) in a 1952? After looking extensively at parts drawings and crawling around under my panel, it looks like a huge job. Thanks in advance for any assistance.
Bernie
1952 master switch replacement
Moderators: GAHorn, Karl Towle, Bruce Fenstermacher
- Bruce Fenstermacher
- Posts: 10426
- Joined: Tue Apr 23, 2002 11:24 am
Re: 1952 master switch replacement
Bernie, it's been a while since I was under my 170 panel. You are right, the job takes some thought, is tedious cause your laying uncomfortably on your back while trying to see stuff in you by-focals that you can't get your head in the right position to do so. Not to mention working one handed.
Assuming the screws are original your looking as slotted screws. Getting them out is the easy part, replacing they isn't. For this job, split screw drivers are the key to not loosing your mind. If you haven't used them before, the blade is split and the knob on the shaft spreads the blade to wedge it in the screw slot, holding the screw. You can't use these screw drivers to loosen or tighten the screw though. https://www.google.com/aclk?sa=l&ai=DCh ... EBA&adurl=
Match sure your battery is disconnected. Remove the electrical bar strapping from the adjacent switch. Get up in there and carefully remove the nut from the master switch which may require some thin wrenches, I don't remember. Remove the switch and replace with the new and reverse the order of disassembly.
Assuming the screws are original your looking as slotted screws. Getting them out is the easy part, replacing they isn't. For this job, split screw drivers are the key to not loosing your mind. If you haven't used them before, the blade is split and the knob on the shaft spreads the blade to wedge it in the screw slot, holding the screw. You can't use these screw drivers to loosen or tighten the screw though. https://www.google.com/aclk?sa=l&ai=DCh ... EBA&adurl=
Match sure your battery is disconnected. Remove the electrical bar strapping from the adjacent switch. Get up in there and carefully remove the nut from the master switch which may require some thin wrenches, I don't remember. Remove the switch and replace with the new and reverse the order of disassembly.
You do not have the required permissions to view the files attached to this post.
CAUTION - My forum posts may be worth what you paid for them!
Bruce Fenstermacher, Past President, TIC170A
Email: brucefenster at gmail.com
Bruce Fenstermacher, Past President, TIC170A
Email: brucefenster at gmail.com
- n2582d
- Posts: 3014
- Joined: Mon Apr 29, 2002 4:58 am
Re: 1952 master switch replacement
Bernie,
To remove the switch bar bracket without removing the plastic overlay you’ll need to drill two small holes in the plastic as discussed here. A small magnet might help in locating the screws/where to drill.
To remove the switch bar bracket without removing the plastic overlay you’ll need to drill two small holes in the plastic as discussed here. A small magnet might help in locating the screws/where to drill.
Gary
Cessna® is a registered trademark of Textron Aviation, Inc. The International Cessna® 170 Association is an independent owners/operators association dedicated to C170 aircraft and early O-300-powered C172s. We are not affiliated with Cessna® or Textron Aviation, Inc. in any way.