Front Side Window Replacement

[C170U2]

Does anyone have any tips for replacing the front window glass on a 1950 170A? From looking at it, I assume the window has to come off, the rivets have to be drilled out, glass replaced, and reinstalled. Cherry max rivets were used all around and the hinges have the ends crimped, so the hinge pin can't be easily pushed out. Looks like I will have to drill the hinge off to get this done. Has anyone done this repair without removing the window? My thinking was that I could remove all the bottom and side rivets, separate the frame enough to slide in the glass and then rivet it back together. Probably a pipe dream. Any ideas would be appreciated.

[Bruce Fenstermacher]

Anything is possible if you have enough patience. So the question is, will the additional difficulty of drilling out and replacing the hinge rivets be more or less than the patience you have to work with half the frame still hanging on the door. I know I'd be drilling rivets out of the hinge.

Unless someone already did this and used Cherry Max, you may not be looking at Cherry Max rivets. Is there a stud in each rivet? I seem to think Cessna may have used more of a pop rivet in the frame assembly at least. That might be my pipe dream though.

[C170U2]

Yeah, it’s been done before. They are cherry max. I was the dummy who used cherry max rivets when I replaced a hinge a few years ago. Guess I’ll just have to grind off the rivet heads and go for it.

[gfeher]

From your reference to hinges, I'm assuming you are referring to replacing the side door windows. If the 170A side door windows are essentially the same as the ones in the 170B, then you can definitely replace those windows without removing the window frame from the door. I replaced mine on my 170B last year without removing the frame. Easy to do. All you need to do is remove the lower half of the trim channel/frame pieces around the window by drilling out the pop rivets holding them onto the inner frame. Then carefully pull down on the windowpane to slide it out of the top half. Remove the old channel window seal material and install the new pane by reversing this process using new channel seal and pop rivets. Use cheap all aluminum (body and shank) hardware-store pop rivets (e.g., Arrow brand) to replace the bottom window trim frame. (I know, it's not aircraft hardware, but they are more than adequate and you do NOT want to use steel shank rivets. I'm an A&P and that's what we use. Otherwise the next A&P who needs to replace the window will be cursing you and will probably damage the frame drilling them out.) Avoid messing with the window hinges at all cost (e.g. drilling them out (especially if the rivets are Cherry Max)), as the door frame is pretty soft and the holes easily can be damaged. Don't mess with the hinges, especially if they are working well!

There's at least another thread somewhere on the forum discussing this.

[C170U2]

Thanks. I'll give it a shot and see if I can get them out without drilling the top rivets. I appreciate the info, exactly what I was thinking would work. I'll post an update when I get it done.

[gfeher]

You shouldn't have any problem. Depending on the condition of the channel seal, you may need to persuade the window to slide out, but it will come out without removing the top trim pieces. One of mine came out easily, the other I needed to persuade a bit. You will need to tap the new pane in from the bottom with a soft mallet to get it to fully seat in the new channel seal, but that's simple. Just use common sense.

[brian.olson]

We replaced both side windows when we had the doors off for our interior refurb a year and a half ago. It's actually pretty simple as the above posters mentioned. We did not remove the window hinge nor did we remove the trim piece attached to the hinge - just the lower trim after drilling out the rivets. A hint that made the installation of the new windows substantially easier: we put the new rubber gasket around the new window prior to install, and just before installing it coated the gasket material with a little silicon lube that we had leftover from the door gaskets we previously installed. Before we used the lube, we tried installing it "dry" and even with persuasion from a rubber mallet, we still couldn't get it in far enough. It make it much easier to push the gasket/window combo into the channels.

[gfeher]

Good tips from Brian, which reminded me of another tip. When you cut the rubber gasket, cut it a little long -- about an inch or two, and put the seam at the bottom. Press the window into the frame as Brian recommends. Then before putting on the bottom frame pieces, trim the end of the gasket to exactly match the other end. This is because the length of the rubber gasket will change a bit when pressing the window and gasket into the frame.

[GAHorn]

Inspect those upper hinges closely for condition and security, however. They are notorious for deteriorating unnoticed... And entire window frames have Departed the aircraft suddenly in flight.
Open the window, and look for loose rivets and worn pins.

[C170U2]

Thanks for all the great advice. I was able to get the hinge pins out by using a drift to enlarge the holes. After I did that, the pins slid right out. Having the window off the airplane made things a lot easier, and I was able to clean and polish everything. Once off, the disassembly was pretty straight forward. The rivets, which I thought were cherry max were some other kind of pop rivet(universal perhaps). The center popped out easily with a punch. I then drilled with a #30 bit and everything came a apart. I only drilled the sides and bottom rivets, leaving the top piece together. I then cleaned everything up and polished the aluminum. I almost took a rattle can to the frame but decided against it. I cleaned them up with scotch bright and left them as is. I didn't want to get rid of the original paint and kind of like the patina. Cutting the glass was easy using an angle cutter and sander to clean it up. I installed the rubber u channel with the slit on the bottom and slid the glass in place. Once together I used non structural pop rivets and the job was done.

For about 30 bucks worth of Plexiglass, this is one of the cheapest ways to really freshen up your airplane! Wish I had done it sooner!

[C170U2]

More photos

[DaveF]

Looks great, as usual.

But you have to stop showing us this, I really don't need another project right now!