The International Cessna 170 Association

My compass started leaking fluid onto my panel.

I removed the face cover from the compass, and it looks like the gasket/seal inside the compass popped off.

Am I able to repair the compass with new seals and top up with fluid? If so, which seals and fluid do I purchase?

Thanks

It is not legal for owners to repair the compass. It is <supposedly> not legal for an A&P to repair them either- only an Instrument Shop.

Having said that, Aircraft Spruce sells several repair kits which you might purchase to investigate what parts the Instrument Repair Shop would install, including the fluid.

Use the forum search function for several previous threads on this investigation.

Buy the Spruce repair kit. Submerge the compass in a bowl of fluid to allow the bubbes to escape before your close it up.. Lasts another 20 years and no operational issues.

(Worked for me on several different airplane compasses and despite the criticism of purists, have had zero problems.Before 1979 no self-respedting A&P or FAA inspector had any problem with it either.)

GAHorn wrote:Buy the Spruce repair kit. Submerge the compass in a bowl of fluid to allow the bubbes to escape before your close it up.. Lasts another 20 years and no operational issues.

(Worked for me on several different airplane compasses and despite the criticism of purists, have had zero problems.Before 1979 no self-respedting A&P or FAA inspector had any problem with it either.)

Is this the correct kit for my compass? https://www.aircraftspruce.ca/catalog/p ... -08000.php

My AME will perform the work, but I have to order the parts. He doesn't live near me, hence why I have to research & order parts before I go see him.

Reece, that is what I would order. Here is the problem. They sell you enough fluid to fill the compass but not enough to fill it and get all the air out. What others have said but not really explained is the only way to get all the air out of the compass is to submerge the whole compass in fluid and be able to rotate compass around while it is under the fluid level.

If you had the perfect container that the compass just fit into, the bottle they sell is just not enough fluid to do this. You will need the perfect container and at least 2 bottles of fluid. If you don't have a perfect container, it may take more.

A quick story. I once visited my friend mechanic flying my Clipped Wing Cub. The compass had a large bubble of air in it. While I was at the airport the friendly FAA safety inspector stopped by the chew my friends butt because the flight school Cessna 172 did not have approved door hinge pins but rather quick pull type pins likely procured at the tractor supply. I was trapped but couldn't see a way to gracefully escape the situation. The Inspector gets done with my buddy and spots my Cub and proclaims "now there is an airplane" or some words to that effect. He asks who's plane? My "buddy" deflecting attention from those horrible door pins, quickly points to me and the Inspector strolls over to my Cub for a quick walk around. Dips his head in the cockpit looking things over then spins around and says "Nice Cub but get your buddy to give you some compass fluid". All three of us knowing it would be illegal for either of us to service the instrument. Go figure.

I still have almost the full quart after buying a repair kit…PLUS a quart of extra fluid …so as to accomplish the “purge”. I pour the quart into a plastic 2 quart bowl and submerge the compass into the fluid…allowing the air bubbles to escape the compass…and complete the assembly beneath the surface.

Afterwards, I pour the excess fluid back into the quart container thru a coffee filter…and store it away for future use.

https://www.aircraftspruce.com/catalog/ ... kkey=12465

Do NOT use kerosene, jet fuel, alcohol, stoddard solvent, or “whiskey”, etc. … because most of those products will eventually turn the compass-legends “yellow” or float them free from the turn-table…and/or will damage the interior if/when it leaks again. Use genuine “compass fluid” sold by Spruce or Airpath.

Also, BE AWARE that some older compasses (usually larger types in Stearman, Waco, etc aircraft) and many of the original instruments in classic airplanes such as ours had their legends made using Radium so it will glow in the dark. Don’t mess with those compasses/instruments. They should be disposed of as a hazardous material. (IE, don’t throw them in the landfill unless your local landfill specifically accepts consumer-level radioactive waste, and don’t handle their parts….and good luck finding an agency that will help you dispose of it. Some local fire departments will accept consumer-level radioactive waste such as fire detectors and small consumer objects.)

here's what the smithsonian has to say on the subject of radium painted instruments...

http://resources.culturalheritage.org/o ... 022-11.pdf

Thanks for posting that, Falco!

Typical of regulatory documents… Lots of verbiage only to conclude “Be Careful.”

What I get from that and other such publications is: To view such low level objects in a museum or in a display is usually quite safe because the viewing is of limited duration and direct contact with the item is not common. However, notice that workers at Smithsonian who are around the instruments are required to wear a dosimeter and are restricted as to contact and handling.

How does this apply to private individuals who own these instruments? Each must make his own decision as to how much one wishes to expose ones’ family members and self if those items are kept in the home. Federal standards require a dosimeter for persons commonly in presence.

I know of no instrument repair station which will accept them for repair, and the postal service doesn’t want them in the mail either.

I disposed of mine at my countys’ hazardous materials disposal day (held once per year.)

Or save yourself all the grief and just buy a new compass. I installed a SIRS a few years ago and like it.

A group of three guys here on the Brighton airport bought a Stinson 10A from a museum in Canada, and on crossing the border back into Michigan late one night they were met by CBP agents wielding shotguns. As it turns out CBP has radioactivity detection equipment sensitive enough to detect the old instruments from inside the trailer. It took most of the night, but they were eventually allowed to enter once CBP determined they weren’t terrorists.

Whenever I clear customs into the US I am met by a border agent with a Geiger counter. I think it’s SOP.

Same here, I think they drag out and wave around the box just to see whether it still works

Topped it up with fluid and a repair kit, good as new.

I'm assuming there was no radioactive elements in the compass, as the last service date was 1990.

Not glowing green

Wendell Wyborny mfr’d a geiger counter/detector for me using an obsolete Soviet detector tube. It has no actual read-out… just a flashing led and audible alarm which increases frequency-of-bleats as the relative radioactivity increases. When I had a CT scan two years ago they injected me with a short-termradioactive isotope, and I energized the detector on top of my bedroom dresser.
As I walked towards the room from our living room I began to hear it “beep” from the hallway and it rapidly increased activity as I neared the room.
48 hrs later, no detection existed as the isotope decayed.

Speaking of compasses, one of our local airports (Hollister-KCVH) actually hired a survey team and realigned and repainted an old compass rose that was probably from WWII. I don't think I've ever seen one of the old compass roses redone.