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  #1  
Old 08-07-2021, 07:46 AM
PandaCub PandaCub is offline
 
Join Date: Jul 2019
Location: Colorado Front Range
Posts: 25
Default Brake Line Flambé

Something to watch for on your RV-14 main wheels:

Yesterday I did a normal landing at my home airport (KBJC) and taxied back to the hangar. About 15 minutes later brake fluid began to drip from the left main. I popped off the wheel pant, only to behold the zip tie(s?) holding the brake line away from the rotor was missing and [what was left of] the brake line had been rubbing against a piping-hot disc!

I now plan to replace the brake lines on both sides and secure them with clamp(s) rather than zip ties.
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John Newkirk
Colorado Front Range/Wyoming Big Horn Basin
RV-14A No. 140308 (N34PB) w/ 330+ Hours
Carbon Cub FX-3 CCX-2000 (N134PB)

Last edited by PandaCub : 08-09-2021 at 08:25 AM.
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  #2  
Old 08-07-2021, 07:49 AM
painless painless is offline
 
Join Date: Jan 2005
Location: Peshtigo, Wisconsin
Posts: 796
Default

Zip ties??
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Jeff Orear
RV6A N782P
Peshtigo, WI
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  #3  
Old 08-07-2021, 08:48 AM
TS Flightlines TS Flightlines is offline
 
Join Date: Apr 2010
Location: Ridgeland, SC
Posts: 2,896
Default

If you like you brake hoses well done, without some sort of steak sauce then do this.
YES--this is one of ours--installed by the previous owner/builder. Seems there was a tire tube issue on the same wheel recently, so there is no way of knowing exactly. The other side was secured. OP reported it to us, but from the pics, I think the liner is intact and would hold pressure. OP did NOT report a brake failure---although now with a caliper leaking, we suspect a severely overheated piston O'Ring. He's changing both calipers ( was going to upgrade anyway) and new hoses---non crispy option.

I'll get the original back and do an autopsy, and share the findings with all.
Tom
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Tom Swearengen, TS Flightlines LLC, AS Flightlines
Joint Venture with Aircraft Specialty
Teflon Hose Assemblies for Experimentals
Proud Vendor for RV1, Donator to VAF
RV7A Tail Kit Completed, Fuse started-Pay as I go Plan, on hold while we develop new products for RV builders
Ridgeland, SC
www.tsflightlines.com, www.asflightlines.com
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  #4  
Old 08-07-2021, 11:52 AM
PandaCub PandaCub is offline
 
Join Date: Jul 2019
Location: Colorado Front Range
Posts: 25
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^^ Tom is one of the most helpful guys I've encountered in the industry and it'll be interesting to get to the bottom of this. As he said, the brake hose itself didn't fail and I'll wager it still works fine (the leak was coming from the caliper and not the hose).

My current theory: I'd recently landed on a grass strip (Gaston's 3M0 - highly recommended) and noticed the RV-14A's wheel pants make a great "scoop" for the dead grass underlying the turf. If enough of that dead grass got into the wheel pant and dried out over the course of a few days, it's entirely plausible that a hot brake disc could ignite it, causing a fire inside the wheel pant after landing and taxi.

I'm currently awaiting new brake lines from Tom and an upgraded brake set from Grove (https://www.groveaircraft.com/rvwheel.html). Will update next week after installation.
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John Newkirk
Colorado Front Range/Wyoming Big Horn Basin
RV-14A No. 140308 (N34PB) w/ 330+ Hours
Carbon Cub FX-3 CCX-2000 (N134PB)

Last edited by PandaCub : 08-07-2021 at 11:54 AM.
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  #5  
Old 08-07-2021, 12:57 PM
BillL BillL is offline
 
Join Date: Sep 2007
Location: Central IL
Posts: 6,227
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Quote:
Originally Posted by painless View Post
Zip ties??
...


What do the plans call for?
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RV-7

Last edited by BillL : 08-07-2021 at 01:02 PM.
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  #6  
Old 08-07-2021, 01:56 PM
Aluminum Aluminum is offline
 
Join Date: Jul 2017
Location: San Jose, CA
Posts: 321
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Quote:
Originally Posted by BillL View Post
...


What do the plans call for?
Flared aluminum tubes fastened to the landing gear leg a foot away from the brake with 3M "self-healing" tape.

Stick to the plans, folks...
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'91 Zodiac 2013-2020 retired
RV-14A wiring
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  #7  
Old 08-07-2021, 02:22 PM
PandaCub PandaCub is offline
 
Join Date: Jul 2019
Location: Colorado Front Range
Posts: 25
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The plans I have show 3 wraps of friction tape around the brake lines and they do appear to be aluminum tubes (U-01414-L and U-01414-R).

(By way of background, I am not the original builder of this beautiful bird. Just discovering more about her as I go along).
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John Newkirk
Colorado Front Range/Wyoming Big Horn Basin
RV-14A No. 140308 (N34PB) w/ 330+ Hours
Carbon Cub FX-3 CCX-2000 (N134PB)
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  #8  
Old 08-07-2021, 02:38 PM
Nova RV Nova RV is offline
 
Join Date: Aug 2015
Location: Leesburg, VA
Posts: 574
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If you look closely to at a Matco master cylinder, you will see the travel from off to full braking is very short, any tiny bit of pressure on the top of the rudder pedal will make it drag. I know of several instances of fires or near fires in the brakes of a -14 and I would bet they are most or all from either pedal pressure while taxiing or a caliper not moving smoothly and dragging. The return spring master cylinder mod is a good idea plus hyper focusing on keeping your heels on the floor and not letting them put any pressure on the pedals, especially on long taxi runs.
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Leesburg, VA

CFI-I ASMEL, ATP

RV-14A kit # 140243 (flying as of 11/18)

www.mykitlog.com/chrismoon/
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  #9  
Old 08-07-2021, 03:29 PM
Brian Perry Brian Perry is offline
 
Join Date: Sep 2018
Location: Saginaw, Michigan
Posts: 40
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My brake lines (from TS Flightlines) came with an adel clamp to hold the line in that position rather than a zip tie.
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RV 14A Kit #140588
Airworthiness Certificate Issued 1/9/2021
First Flight 1/23/2021
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  #10  
Old 08-07-2021, 05:04 PM
G-force's Avatar
G-force G-force is offline
 
Join Date: Jun 2006
Location: Castaic, CA
Posts: 562
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I would think that a much closer inspection of mounting systems of plumbing, hoses, etc is warranted, especially in hot places like under the cowl. Where else were zip ties substituted for proper fasteners? And other places something wasn't plumbed/wired/rigged per the plans.

[quote=PandaCub;1546245
(By way of background, I am not the original builder of this beautiful bird. Just discovering more about her as I go along).[/QUOTE]
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