Gear Bolt Mod

Time: 5 Hours

If you remember in my previous blog posts I did quite a bit of work to the landing gear towers to open them up and make it easier, relatively speaking, to access the landing gear bolt nuts. The boats go up through landing gear into the landing gear tower where the nuts needed to be torqued. This task has proved to be very difficult for many builders as there’s not a whole lot of room in the towers. Not too long ago my buddy Glenn and I read about another builder and some clips he was making and selling. These look very cool to us and thought we would try them! What they are is a couple pieces of strong steal U-channel that is just wide enough that the head of the gear bolt, when turned correctly, fit in between. A hole is drilled to allow the bolt to slide down through and the head be sandwiched between the two flanges of the U shape. Here are a couple photos to better describe what I’m talking about. 

   The theory here is that the bolts would be installed backwards or down through the gear towers and the gear legs versus up through them. This metal clip would then bind against another nut in the tower to prevent it from spinning. What this allows is the nut to be placed on the bottom of the gear legs, easily accessible to torque with just one person as the bolt head would remain stationary due to these clips. 
 After five hours of swearing, removing various nuts, holding back wires that are run and moving brake lines I was able to modify and manipulate these clips along with the bolts to finally get them in their final position! The clips needed some modifications to fit around other nuts that are in the gear tower as the tolerances are pretty close in the space. So you read that correctly five hours to install four bolts! The first picture shows you the normal condition with the nut inside the gear tower and how hard it would be to get a socket and torque wrench in there to adjust these. The second photo shows the mod with the bolts going down through.
   I did buy new gear bolts to adjust for the slight increase in thickness of the clips as well as to address the original bolts that were only showing one maybe one and a half threads. I ordered new bolts from Genuine Aircraft Hardware and adjusted the bolt I ordered. The original bolt was a close tolerance NAS6206-27 bolt. I ordered a NAS6606-27 bolt to replace it. This new bolt has the same grip length just a little longer threaded portion which adds to the overall length of the bolt by about 1/8″. Now I have 2 to 3 threads showing outside of the nut as it is torqued. As for was this modification worth it in the pain in the butt it it was to get these bolts and clips down in the tower? A definitely yes as it took me 10 seconds to torque the nut and I could do it all by myself. These bolts and nuts will need to be torqued every one hundred flight hours and this mod allows me to do that by myself very easily. So a little hardship now will pay off greatly in the long term, I only wish that I had done this mod back when I was assembling the landing gear which would’ve made it so much easier!