I want to install hinge pins in both doors of my C170B project that I have seen with the large hoop on top that makes removal easy.

Q1: I have ground off the flared ends of the existing hinge pins, but three seem to be rusted into place and will not move, even with a hammer and punch. Any other ideas to remove old pins?

Q2: Where does one get the new pins with the hoop? I believe they are stainless steel.

Thank you,

John Nielsen

John,
I have the pins in my door also and I think they are SS welding rod that has been bent. Mine don't have a loop, they just have a 90 degree bend. In regards to getting the old pons out, can you remove the hinge from the door? Soak with a good penetrating oil and heat. Or just put it in a jig/vise and drill it out. My $.02

john54724 wrote:Q1: I have ground off the flared ends of the existing hinge pins, but three seem to be rusted into place and will not move, even with a hammer and punch. Any other ideas to remove old pins?

Give some Kroil a try to loosen them up.

http://www.kanolabs.com/

Chris

Both doors/hinges are currently off, so I will try some of the magic oils suggested..
Keep the ideas coming.
Thanks.
John

Here are some pins, though they are not cheap: http://www.fadodge.com/index.php?option ... &Itemid=53

John,

I got the pins from Dodge. Buy one extra....they disappear in grass.....don't ask how I know. I've seen them attached to the airframe with light cables, but seems a little over the top.

MTV

+3 on the FA Dodge pins. For a good penetrating oil, google ATF + Acetone.

My god, don't buy them! As mentioned earlier, they are just SS welding rod (when I went to AirGas, they just gave me one rod for free). Cut a piece 2" longer than you need. Chuck this now 3-3.5" piece of rod in a drill, Run the drill as you use a file to sculpt the nose of the rod into a cone. Finish with some 400 sandpaper to make it smooth. Now put the rod into a vice and use an old piece of pipe as a guide and bend the other end around it to make the loop. Trim the loop to make it the desired length and file the end smooth. Gosh, this took all of 5 minutes. Make about 15 from one piece of rod. You can just make it a simple L, if you like or chose from one of the millions of available polygons you feel competent to bend it into. If your talented, make a set with one of your initials on top and the other on the bottom. For the door stop, you can get some of the Steel Safety Pins to use instead of a cotter pin:
http://www.aircraftspruce.com/catalog/hapages/cowlingpins.php?clickkey=13442

This is what I have, at 44 cents each they dont break the bank. 26.50 for the FA Dodge pins seems a little ridiculous.


http://www.aircraftspruce.com/catalog/h ... kkey=13442

If I put in those pins instead of the old rusted in place pins, will I completely lose the false sense of security I get when I lock the door?

Certainly on my 170 that sense of security is extremely limited. I can open the door with it still locked, or use the tip of any carkey to unlock the door:)

You might get a pair of ViseGrips or side cutters on the top side, and hammer to pull out the pins. But I've found it sometimes wasn't the corrosion holding onto a hinge pin, but the stepped wear marks that were grabbing on to the hinge. Realignment of the hinge and gentle tapping was the only thing required after realizing that.

I have not replaced my door hinges, but on other hinges I use drill rod rather than stainless. Stainless won't rust, which is awesome, but it is hard, and can worry into the hinge material. I would personally rather have the rod worry rather than wear on the hinge. You can buy exactly the right diameter you want at a good hardware store too. It anneals reasonably soft so you can torch it and make a nice bend or a ring for a small wire lanyard, which is available for less than $2 at McMaster Carr. I use them on my quick release rear seat to keep the pins attached to the seat after seat removal.

Good luck.

If you got the hinges off the doors, you're doing better than many of us who have broken or stripped the screws holding the hinge onto the doorpost. When you reinstall the hinges, consider getting good quality, hardened Torx head screws or small hex bolts instead of the AN screws. Some of the AN screws are softer and lower strength, and can more easily be stripped out by the screwdriver tip. Using hardened screws means that the hardened screwdriver or Torx tips will not goober out the head as quickly , leaving you with a poor man's "anti-theft" fastener.

On my project, I fully intend to run a tap through the nut plates inside the doorpost, thus eliminating the oval "self-lock" part of the system. I'll lubricate it well with moly grease, and then safety wire or lockwasher the screws or bolts in place. This may or may not be acceptable under an overly draconian interpretation of Part 23 or Part 43, but I believe the ease of maintenance is well worth it, and it does not harm the structural integrity of the airplane. It essentially substitutes one Part 23 / Part 43 approved safetying method for another.

In your procedure for removing the old rusted pins, you can wiggle the hinge to determine which side of the hinge that the pin has seized. That way, you can put the correct half of the hinge into the vise, so you are not hammering on the wrong part.

+1 on the mixture of acetone and ATF fluid. There had been some published test that showed this mixture was superior to commercial oils.

Also, use several warm/cool cycles with a hair dryer or heat gun to expand and contract the hinge lugs. As they expand and contract, use an engraving pen to vibrate the hell out of it all, which will allow the ATF mixture to creep in. If you have room to do this, you can also spray some kind of aerosol propellant on the pin to cool/shrink it, while the hinge lugs are heated and expanded.

BTW, big difference between hardness of welding rod and hinge pin. Stainless hinge pin (or piano wire) will more times then not fracture when you try to bend it, whereas welding rod is quite soft and malleable.