Replacing the main landing gear bolts

[Bryan Cotton]

I know when the service bulletin came out to replace the stainless bolts, a lot of people did this. I thought I'd document it.

Here I have hoisted up one side:

On my A model, there is not enough space for the nut and extra threads by the firewall, so I put the bolt head against the firewall. This means you need to cut off the head to get the bolt out. To make space I jammed some wood between the engine mount and firewall.

Next Mr. hacksaw made an appearance. I considered the Dremel cut off wheel but the fuel vent is close and that seemed hazardous.

For safety, a sign as we have a couple pilots that fly the airplane.

There is a little slop in the right gear leg socket. I'm going to bond the gear leg in with Met-l-weld ( aviation quality JB Weld) and replace the bolt.

To be continued...

[Bryan Cotton]

I made a special drill bit to pilot a hole. Took a 1/4" steel rod, bored a 1/8" or so hole in the middle, and pressed in a part of a #30 bit. Then I sort of squashed it around the edge.

I also chucked this up in the lathe and put a taper on the end by the #30 bit. Then I transferred the hole:

With the #30 pilot hole in place it was pretty easy to upsize to 1/4". I deburred the outside of the firewall with a file, and the inside with a deburring tool. That was a pain.

[Bryan Cotton]

I made a couple of 1/4" thick aluminum spacers to take up the gap. New bolts are AN4-32.

My right gear had a little slop in the socket. I put it back in with some met-l-weld. Basically aircrafty JB Weld from ACS.

It is cured now and no more slop.

My original bolt on the right side looked fine.