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Brake groan update

Daddyman58

Daddyman58

Well Known Member
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I have experienced an annoying loud groaning when I applied my left brake. The brake functions normally, and stops straight. But the noise was bothering me (and perhaps others).
I examined it closely, and could not see anything that would cause the mystery noise.
Yesterday, I couldn't stand it any longer, so I jacked up the plane and lo and behold- I was what was the likely culprit.
The spacers I created out of soft aluminum tubing had become deformed under excessive torque to the 3- backing plate bolts.
The lowers of the backing bolts had cracked the backing plate bolt hole off (P/N 810-L) around the bolt. It was not visible until I removed it because the bolt still captured the broken ear.
With only 2 bolts to hold the wheel support flange was able to vibrate and hence the noise.
I make a temporary repair and ordered a replacement part from Van's which is on the way.

Test taxi and flight confirmed the noise-maker cause.

Daddyman58
 

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There was a thread on this (or a few threads on this) ...

The U-408 spacers tend to deform over time; Van's was supposed to change the kit to provide for steel versions, but I think this got tabled due to Chapter 11 & its distractions.

McMaster Carr part 93441A432 (https://www.mcmaster.com/93441A432) should fit the bill...

Or if you are excessively cost conscious use 7 AN960-416 washers in lieu of the U-408...You might need to grind them down a bit to fit (.375" vs .5")
 
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Daddyman58 said:
I have experienced an annoying loud groaning when I applied my left brake. The brake functions normally, and stops straight. But the noise was bothering me (and perhaps others).
I examined it closely, and could not see anything that would cause the mystery noise.
Yesterday, I couldn't stand it any longer, so I jacked up the plane and lo and behold- I was what was the likely culprit.
The spacers I created out of soft aluminum tubing had become deformed under excessive torque to the 3- backing plate bolts.
The lowers of the backing bolts had cracked the backing plate bolt hole off (P/N 810-L) around the bolt. It was not visible until I removed it because the bolt still captured the broken ear.
With only 2 bolts to hold the wheel support flange was able to vibrate and hence the noise.
I make a temporary repair and ordered a replacement part from Van's which is on the way.

Test taxi and flight confirmed the noise-maker cause.

Daddyman58
Click to expand...
You are supposed to use the 2024 thick wall tubes there, not the soft stuff. I have the same setup on my 10 that weighs a 1200 lbs more with no deformation of those spacers
 
lr172 said:
You are supposed to use the 2024 thick wall tubes there, not the soft stuff. I have the same setup on my 10 that weighs a 1200 lbs more with no deformation of those spacers
Click to expand...
Ir172,
Figured that as soon as I saw the deformation.
The final fix will be with the thick-walled stock.
Daddyman
 
lr172 said:
could catch. I guess it was my just my own modification. I must have looked at it and thought no way that 6061 works here. 2024 is a good bit harder.
Click to expand...
Larry -- You are a steely eyed missile-man... :)

IIRC Van's didn't provide tube in 2024-T3; The only aluminum tube stock that I was provided was AT.375-.058 (looking back at Chapter 4 now...)

If they did update this when they transitioned to Matco, it sure would have been nice for them to let folks know ( sort of a basic Sustaining Engineering 101/Customer Support 101 thing ) FWIW, my DWG C2, Revision R2 - 11/13/2000, was supplied with my '2015 -7, which had Matco wheels/brakes.

Scott McDaniels told me about the change to alternate material just before he retired.

Net-Net
If you've got the groans, it's not the from the questionable shrimp -- it's probably the squishy aluminum spacers.
 
To beat a dead horse:
I looked up the yield strength of 2024T3 vs 6061T6. The 2024 is only 18% higher. The yield strength of 6061 is comparable to the steel in post #3 Is there any possibility this is not .058” wall tubing?
 
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Mikeyb said:
To beat a dead horse:
I looked up the yield strength of 2024T3 vs 6061T6. The 2024 is only 18% higher. The yield strength of 6061 is comparable or stronger than the steel in post #3 Is there any possibility this is not .058” wall tubing?
Click to expand...
Tensile strength is resisting pulling apart - tension. Compressability is completerly different. Harder materials will reduce ductility and compressability, which is what you are after in this application. IIRC, 2024 is hardened to a significantly greater degree than 6061. You notice this in cutting and drilling it. 2024 drills like steel and 6061 like somewhere between copper and steel. 6061 bends easilly without cracking and 2024 does not; again an indication of greater hardness.
 
....and the moment we've all been waiting for --- the updated DWG C2. Drawing updated to R3 August 19, 2022

U-408 has been superseded by U-00408-1; Same dimensions - material changed to 4130 steel

Screenshot 2025-03-14 at 2.29.34 PM.png
 
Sean from Planearound makes a machined spacer for the 10----- https://planearound.com/shop/ols/products/two-wheel-fairing-bracket-spacers-for-rv-10-set-of-two

This upgrade make a whole lot of improvement in our 10 pants mount.

Totally agree about heat and not using Nylocks. All metal lock nuts are the way to go.

He may also make one for other models, if not, this design offers much better support than just a couplethree pieces of tubing.

Pretty easy to fab for your specific needs, methinks.
 
Anyone have a source for this U-408 in 4130 steel except made 13/32 length for the original Cleveland 30-9 plans?

If Not I was thinking of doing a group buy and have 10 sets machined to reduce the unit costs.
 
klong66 said:
Anyone have a source for this U-408 in 4130 steel except made 13/32 length for the original Cleveland 30-9 plans?

If Not I was thinking of doing a group buy and have 10 sets machined to reduce the unit costs.
Click to expand...
just buy 4140 tube from mcmaster. mild steel is also plenty strong for this application, with a lot more wall thickness options.

If you want to set up a group buy, feel free to DM me and I'd be happy to make 10 or 20 or however many are wanted to whatever exact specification you need for a reasonable fee.
 
I tried making this part by cutting off and then using a sanding disk. Could not get the ends squared.
Which leads me to believe a lathe is probably needed to get the ends squared and the length cut at the correct dimension.

Open to other ideas or suggestions on how to get the dimensions correct and consistent along with squaring off the ends?
Thanks
 
klong66 said:
I tried making this part by cutting off and then using a sanding disk. Could not get the ends squared.
Which leads me to believe a lathe is probably needed to get the ends squared and the length cut at the correct dimension.

Open to other ideas or suggestions on how to get the dimensions correct and consistent along with squaring off the ends?
Thanks
Click to expand...
If you have a decent drill press: block of wood on the drill press table, fine tooth mill file on top of the wood. Chuck the bushing and using moderate s[peed bring the bushing down on the file. Heavy welding glove on hand holding the file. Be careful!! I have been doing this for years and never hurt myself. If you have a decent disc sander with a table, square one end of the tubing then cut the proper length and use the drill press.
 
jrs14855 said:
If you have a decent drill press: block of wood on the drill press table, fine tooth mill file on top of the wood. Chuck the bushing and using moderate s[peed bring the bushing down on the file. Heavy welding glove on hand holding the file. Be careful!! I have been doing this for years and never hurt myself. If you have a decent disc sander with a table, square one end of the tubing then cut the proper length and use the drill press.
Click to expand...
Thanks for that, I tried using this method with assistance and it seems to work pretty well. We were able to make 4 of them .405, .406, .407, .406, I’ll make the final two pieces tomorrow.
 
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