A Maintenance Oriented Podcast For Airplane Owners, Pilots, and Mechanics

Month: April 2026

259 – Bonanza Clunking Wheel Noise Solved!

When Dan, the owner of a nice A36 Bonanza called me and reported a “clunking noise” at the right main landing gear while moving the airplane by hand, I was stumped.

So I did what I like to do when I have an airplane puzzler… I sent an email to my aviation friends, and I asked for ideas about what might be causing this clunking noise.

I received great feedback and guesses about what might be causing the mystery noise.

Wheel bearings? Brake caliper / linings? Landing gear bushings? Etc…

But when Dan arrived at SHD to drop his airplane off for the annual inspection, it was no longer making the clunking noise.

We agreed I’d check it out during the inspection.

When the time came to put the airplane on jacks and remove the right brake caliper and wheel, I did not notice anything obvious.

And then I noticed something.

There was a tiny spot on the brake disc that I could catch a fingernail on. Check it out:

(And by the way, if you are seeing these show notes in a podcast player like Pocket Casts, the following 11 second video may not appear; if this happens, scroll to the bottom and click the link for my website and you should be able to watch the video there.)

I also made a more detailed video of this story and it’s on YouTube here:

https://youtube.com/shorts/XuTnm-qQne0

Then I also noticed there was a groove on the brake linings that seemed to match the spot on the disc. Take a look:

It appears there was some metal transfer between the brake disc and linings that created a raised “bump” and I wonder if this is what caused the clunking noise as the wheel was rotating during ground tugging. It’s the best explanation I can come up with.

Both the left and right brake discs were worn below minimums, so I installed new ones along with all new linings.

I installed APS “Blacksteel” discs and APS linings. In my opinion, the APS discs are of exceptional quality, and the APS brake linings are far superior to the Rapco linings I removed.

If you’re interested in more info about APS brake parts, here’s the website:

https://www.apsbrakes.com

Listen to the audio for more details.

Now, one more thing I forgot to mention when I was recording the podcast episode… when I removed the right brake linings, there were some strange, seemingly magnetized little pieces that were attached to the brake lining and backplate. Here’s what it looked like:

Perhaps this tells a part of the story as well, but I’m not sure what it means. If you have a thought on this, send me an email to dean{at}airplaneownermaintenance{dot}com


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258 – C’mon Does Valve Lapping Really Work?!


This exhaust valve in a turbo-normalized A36 Bonanza looks quite good. The appearance is mostly concentric and uniform. There’s just that one area at about the 10 to 11 o’clock position that looks slightly uneven.

If the compression test had been good, I likely would not have lapped the valve.

But since it was 44/80 when the required minimum was 46/80 according to the master orifice reading, I lapped the valve in place, installed a new rotocoil and new valve springs, and put it back together.

Amazingly, after doing this work, I got a good solid cold compression of 65/80!

I’ve found that lapping the exhaust valve and restoring a good seal between the edge of the valve and the seat is the most effective way to improve a low compression number, as long as everything else looks good in the cylinder.

Here are some additional photos of the seat area before lapping:

You can listen to the full story in the audio for this episode.

I’ve also included some email feedback from the last episode, including a story about an airplane that made a precautionary landing in a field!

Here’s a totally separate photo of that same airplane from one of its scenic flights:

Thanks Justin, for agreeing to let me share your amazing story of landing this airplane in a field!


The post, “258 – C’mon Does Valve Lapping Really Work?!” appeared first at AirplaneOwnerMaintenance.com