The International Cessna 170 Association

I’m all IN FAVOR of getting your “mousetrap” springs from Bruce….but the tension springs modification as per the later 172 door latch is more attractive and durable, IMO. If you wish to stay Original however…. get them from Bruce and forget about Cessna on this item. Understand that when you order from Bruce you are installing parts under the “owner produced parts” FAA allows. (No problem at all….just making certain no one is confused about this. If you have your A&P install the springs mfr’d by Bruce be certain (only necessary if he asks) to tell him they are approved under the provisions of “owner produced parts” provision …IF he questions it at all. Frankly, there’s NO REASON for him/her to question it, IMO. They are perfect replacements and perfectly legal.

ravenaviation wrote:Let me make sure I have it.

There is another spring in there, PN 0411554 Spring-Door Latch. It appears to my mind that this spring isn't actually needed to close the latch because the pressure is provided by the connecting rod (pull bar) that goes through to the catch from the pin that is on a pivot bracket. Right?
....

Finally, to install the springs a small hole needs to be drilled on each side of then Door Latch Housing PN 0511112-2. Right.

John, to answer your first question, if PN 0411554 Spring-Door Latch is broke, the only way that latch comes out and keeps the door from opening is movement of the pull bar that will just so happen to move the latch into position, if your lucky. There is no pressure on the latch provided by the bar. The latch spring is the only force moving the latch out and holding the door handle in if you have no door handle return spring. The 0511119 door handle return spring was not part of the mechanism until serial 25373. The spring can be retro fitted to all mechanisms and gives a positive closer to the door handle and takes some load of the door latch return spring.

If you install the Cessna kit, you do not have to drill any holes. You simply hook the spring to a convenient spot in the mechanism.

Just completed this repair on my right hand door. Whatever spring was operating the latch previously had broken and the door would not latch at all.

I ordered two sets from Bruce since the left hand door is acting up a bit as well.

Bruce’s excellent illustrated handout helped to make sense of the installation since it is not intuitive. Thanks this is another reason I am a huge fan of this forum.