Rudder pedal contacting brake cylinder

[JimNelson]

This seems to be a good opportunity to learn more about the ins and outs of my 170A. I was practicing crosswind landings, and on the last one the rudder pedals seemed a little "loose". I noticed something a little off on final and really noticed it once on the ground. Taxi back and do a little debugging.

On final and rolling out I felt a little "thunk" as the right rudder pedal hit something. Looking closer, with full right rudder, the bottom of the right pedal hits the brake cylinder. It's never done that before. The normally black cylinder now has a shiny spot where the bottom of the pedal hits it. If I apply the brakes and go full right rudder, the bottom of the pedal moves back enough so that there's a little more travel. Left rudder seems normal but it moves a little easier than I remember. I didn't check full left rudder from the right seat, but I suspect that it's the same as full right from the left. Moving the rudder by hand seems normal, and the rudder cables (as much as I can see) seem normal.

That's all I have for now. If anyone has any ideas about where to look next or if I'm not seeing what I think I'm seeing, please let me know. This learning curve is pretty steep right now!

[GAHorn]

Obviously you have some inspecting to do for damage and wear.

Sounds as if you might find severe rudder-pedal wear at the pivot, perhaps even worse than / like this:

EEEAC829-9B11-4A9E-A7DE-FE80FE4E3E9C.jpeg (26.25 KiB) Viewed 2565 times

And fix it like this:

3E2F0899-DF7D-424E-87E0-FCABD60425A4.jpeg (23.78 KiB) Viewed 2565 times

OR you might even find the pivot has fallen out due to missing cotter, etc.

[Bruce Fenstermacher]

The Pedals are rigged away from the firewall appropriately by loosening or tightening the rudder cables. Many people/mechanics do not realize this. And if one of your rudder stops was suddenly removed, you'd be able to push that side pedal farther towards the firewall and into the master cylinder. So you really have to inspect the entire system, from the pedals to the rudder.

We've had threads in the past that describe the correct rigging for the rudder pedals. I'll try to dig up a link.

Here is a post I wrote in a longer thread:
viewtopic.php?f=24&t=1719&p=102953&hili ... ig#p102953

[JimNelson]

Ah, I was afraid of that. If the pedal was worn I think it would have failed over time. This was sudden. Is there something I can do to confirm that the rigging is out? Or the pedal hitting the cylinder is the confirmation?

[JimNelson]

Thank you all for not laughing too loud as I tried to describe the problem

Two important lessons:
Don't go poking around in dark unfamiliar places without glasses and a flashlight.
Don't try to remember what I saw in a dark unfamiliar place three days later.

A little more debugging. It looks like I run out of right rudder pedal before I run out of right rudder. Left pedal works fine. Right seat both rudder pedals work normally. Cables are all tight. Right rudder pedal doesn't touch the brake cylinder, but rather the metal tube that the pedal attaches to. Looks like the pedal is getting a little bent from that contact.

Time to call in my A&P who knows what he's looking at.

[n2582d]

Good move in calling in your A&P. The 180/185 uses the same p/n 0411306-1 for the right rudder bar torque tube. On the floatplane it was the subject of Canadian AD CF-73-05. The blocks that hold these bars are now made from plastic and have been know to crack. See here. Finally, here's a good article by Flight Safety Australia that highlights things to inspect in this area.

[JimNelson]

Called the A&P and described the problem. He agrees with you that it's probably a cracked rudder bar or bearing. He'll take an external look at it later today but can't get it into his hangar for repairs for a couple weeks as he's totally swamped. Glad it happened on the last practice landing of the day and not on a long cross country flight. I'll post an update when I know more.

Thanks for all the advice! And for all the help even with my less-than-great problem description.

[c170b53]

Could be your rudder pedal return spring has broken. Hoping for an easy fix but I’m often amazed that this area of our planes is overlooked at annuals. I base that observation on the condition I often see, years of muck suggesting the area has been neglected, debris suggesting the area has not been recently disturbed and loose or worn components. In terms of importance, Its vital that these components next to the tail spring are subject to consistent observation at least at annual. This area should be cleaned, the rudder bars lubed, the brake cylinder fluids topped up and included in an area inspection, a detailed inspection of the the cylinder attach points. All easy stuff, so no idea why its not being done.