Door Latches

wa4jr · Post by **wa4jr** » Mon Dec 16, 2002 3:22 am

I have a right door latch system that is not working properly. Seems the springs are weak or missing. The little "pie wedge" locking piece will not extend from the door very easily and fails to engage the striker plate many times. The one on my left door has strong spring pressure and engages the striker plate on the door frame very well.
I am at the point of taking the works out and repairing it per the Association SRAM. I recall seeing in the latest Flypaper a blurb on a rotary latch kit sold by the Association. Can anyone fill me in on the details. I'd rather upgrade to a better latch mechanism than repair the old one if cost is not much of a factor. Does anyone have any details on the rotary latch kit??

zero.one.victor · Post by **zero.one.victor** » Tue Dec 17, 2002 2:11 am

The rotary latch set-up advertised in the Flypaper is being sold by John D Benham,one of the Association's founders,not the Association itself. I don't know if he has one,or several. He's asking $400 for the "kit".
When you say "if cost is not much of a factor",remember it's all relative. If it was me,I'd repair the old latch. If it's like mine was,it just needs a new spring,p/n 0411554,looks like the spring off a small mousetrap. You can buy one from Lee Chavez for $7.50,email him at chavez@gotnet.net. I got onto him thru the 120/140 Club,bought a spring,it works great.
Or you can make one yourself,like I did later. Check out the 120/140 Club website--www.cessna120-140.org . Click on library-diagrams,then click on door latch. It'll take a couple tries,but they're not hard to make. I wish I'd checked out the how-to before I spent my hard-earned 7.50 for a spring that Lee probably made himself. Hardest part is finding the music wire at the damn hardware store.

Eric

bward · Post by **bward** » Tue Dec 17, 2002 3:19 pm

zero.one.victor wrote: Hardest part is finding the music wire at the damn hardware store.

Eric

Music wire usually, is easily found in the local hobby shop. K & S has displays of 18" and 36" lengths in various diameters.

Post by **GAHorn** » Tue Dec 17, 2002 5:05 pm

While $400 is certainly not as cheap as one might hope for it does save some time and effort, and John D. Benham tells me his kits include the STC to make the conversion. If you've got the time and enjoy the chase for a little effort and some scrounging at salvage yards, the same parts in the same or similar condition can be found by an enterprising and frugal owner, but he'll still have the adventure ahead of him to get field approval. John D. emphasizes that his kits are made up of salvaged, serviceable parts for much less than Cessna charges for new parts. (He says Cessna charges $600 for just ONE of the castings that are part of one door.)
The rotary latches are indeed a good mod. I was fourtunate enough to find them already incorporated on my airplane and they are much more robust with more positive latching and locking action than the original. The later rotary-style are also less likely to break and more easily repaired than the original door latches, because their parts were used on and common to more models. The conversion is not something the average owner can perform. You will likely require the services of a good A&P with sheet-metal experience for about two day's work. (Is it worth $400 plus a couple more hundred in A&P fees? I don't know. If you are already in possession of an airplane that has warped doors and lousy paint, you might look for a set of complete 172 doors and get the door-jamb hardware to accompany it at the local salvage yard, before getting too far into a restoration. But if your airplane has already been restored and you're simply having latch problems, then contacting him or searching the bone-yards might be the best way out.)

zero.one.victor · Post by **zero.one.victor** » Tue Dec 17, 2002 7:39 pm

gahorn wrote: You will likely require the services of a good A&P with sheet-metal experience for about two day's work. (Is it worth $400 plus a couple more hundred in A&P fees?.)

George,I don't know what wages are down in Texass but here in the northwest the "shop rate" at a regular a/c maintenance shop is usually around $50 an hour. An independent A&P working out of his personal hangar or out of his car/airplane at your hangar (no overhead) is gonna be at least $25 an hour,if not more.Two days work by the indy is therefore gonna be at least another $400. Then,ya gotta find an IA to sign off the work & do the 337,he'll need to be paid too--nobody's doing this stuff for just for the fun of it!
So realistically,you're looking at 800-1000 bucks by the time the dust settles. Wow! Cost ya about $15 (& your time) to replace the springs in both doors,buying Lee's springs.Less if you make your own. I think The 170 Book & the SRAM book both have articles on how to do it.
I'm not unhappy with the stock latches,even with a bad spring all ya gotta do is push the inside handle to the latched position & it works fine. By the way,I reversed the handles on mine so they face forward,pull up to open & push down to latch--safer that way,as well as easier to reach from the front seat.

Eric

wa4jr · Post by **wa4jr** » Fri Dec 20, 2002 3:29 am

Whew! Now I really like my ratty latch in the right door! If I paid $1000 total for all the parts, paperwork and services to get the rotary latches on my doors....I'd be out at the airport every day just opening and closing my doors to get some value out of the mod....and also because I'd be living there if my wife found out how much I paid for them! If I had the rotaries when the plane was purchased, that would be one thing, but $800 to $1000 HOLLLY JUMPIN JEHOSAFATS! Of course if I EVER did the rotary latch mod, don't you know those little things would just hop in there during the night without anybody every knowing

I'm going the <$10 dollar route using the directions in the Association SRAM!

Post by **GAHorn** » Fri Dec 20, 2002 6:11 am

When it comes to buying an airplane, it's sure nice to find one in your price range that has the mods you want already incorporated. I have to admit, my airplane only appears fairly original. When I think of all the neat things the restorer did to it, I realize I didn't pay anywhere near too much for it. Besides the interior and engine and paint, he did rotary door latches, Pponk gear, all new exhaust, cables, pulleys, wiring, glass, Cleveland wheels and brakes, solid axles, HatchLatch door stops, BAS tail-pull handles, super sound-proofing, epoxy polyamide corroson-proofing, ....
I'd hate to want all those, have to pony up for them, and then face installing them too!

Curtis Brown · Post by **Curtis Brown** » Fri Dec 20, 2002 5:39 pm

A while back my pilot side door latch would not catch. It was the little spring! I found a spring at Ace hardware for about $1 and with a little customizing got it to work. However, getting to the spring and replacing it was an all day project for me and my mechanic. I think he charged me a couple hundred bucks.

wa4jr · Post by **wa4jr** » Sat Dec 21, 2002 3:52 am

I'm just going to take the door off and take it home with me to work on it in the heated garage. Plenty of time to take the inards to Lowes and match up a spring. Will tape a garbage bag over the doorway since I am still stuck outside on the ramp. Don't have new avionics in yet, so no worry. Hey just thinking...does anybody have doors that lock? I have key cylinders on the doors, but they don't do anything...and neither does the little locking lever on the inside of the door.

George...those door stops you mentioned...do they consist of an aluminum fitting that rivets to the door and contains two spring-tensioned ball bearings that act on a "articulated bulb" sort of thingie slung on a bracket under the wing to hold the door open? If so, where can I get a new fitting for the door. A gale blew my right door open last month and smashed the aluminum door fitting in two. I can fix it with a backing plate and some JB weld, but would rather have a new one.....that is if it doesn't cost more than a new door!

zero.one.victor · Post by **zero.one.victor** » Sat Dec 21, 2002 6:17 am

John,it sounds like you're describing a "Sky Catch" door retainer. The Hatch Latch is a little different,made outa nylon. I like the looks of it better,plus the seller advertises (or used to) in the 170 news. I think you can get a SkyCatch thru spruce or one of them places. They also advertise in T-A-P--R.W. Traves Associates, 5555 Columbia Rd,Medina OH 44256 no phone number listed in the ad.$18 a side.

Eric

Bill Venohr · Post by **Bill Venohr** » Sun Dec 22, 2002 4:25 am

The door locks on my plane both work--the locking lever just rotates down into a slot in the door frame. Of course I'm not sure how hard it would be to pick the locks. I know airplane locks are notoriously bad. I can use the key to the locks on the camper shell on my pickup for the ignition key.

doug8082a · Post by **doug8082a** » Sun Dec 22, 2002 2:02 pm

The locks on my '52 work - the pilot's side is keyed and the co-pilot's side has the knob on the door you lift to engage the lock from the inside. Ditto Eric on the Hatch Latch door stops. I put them on two years ago and they work great. Williams Aircraft - San Angelo, TX sells them. Check the 170 News for his ad. I had my own little adventure in installing them, but that's another story.

Doug
'52 170B

Dave Clark · Post by **Dave Clark** » Sun Dec 22, 2002 2:49 pm

I need to find a set of brackets that go on the wing for the door retainers. Mine are very poorly patched and welded.

doug8082a · Post by **doug8082a** » Sun Dec 22, 2002 7:39 pm

Dave, Williams Aircraft sells them already setup for the Hatch Latch. The bracket has a nylon unit with a ball-end that engages the HatchLatch receiver. The receiver attaches on the inside of the door over the existing hole for the old door stop so it's basically invisible. I think I paid $60/side for mine.

Mine were pretty beat too. Of course, getting them off was an adventure. Lot's of labor & cursing for a $60 part.

Dave Clark · Post by **Dave Clark** » Mon Dec 23, 2002 2:55 am

Thanks for the tip Doug. That's what I'll do.