Home > VansAirForceForums

- Donate yearly (please).
- Advertise in here!

- Today's Posts | Insert Pics

Old 06-15-2019, 04:46 PM
jwilbur jwilbur is offline
Join Date: Dec 2010
Location: Culpeper, VA
Posts: 668
Default Brake fluid leak

Taxing the RV10 back to the hanger recently I realized I had no right brake. Pedal went down with no resistance. Thankfully I was close to the hanger.

After getting the airplane into the hangar I intended to remove the wheel pant but it was too hot to even touch.

I got the pant off today and based on the black all around the bleeder valve I assumed that had failed so I replaced it. As I began to pump fluid back in I realized the leak is somewhere else. Before I start taking everything apart, I figured I post a picture here and see what advice I might get.

You can see in the picture from where the fluid is gathering and dripping. Anyone care to venture a guess what I'll need to do/replace to fix this?

-Joe Wilbur (N520LW)
Phase II - 11/2017
First flight - 8/2017
RV-10 Build Log
Reply With Quote
Old 06-15-2019, 04:56 PM
Vlad's Avatar
Vlad Vlad is offline
Join Date: Oct 2008
Location: Utah
Posts: 7,938

Check the connection on top of the caliper. If not, likely the O-ring around the piston is not sealing. Might be the pad wear was too much and uneven which could dislodge the piston. An easy fix. New brake pads and O-ring needed.
Where is N666BK?

Не имей сто рублей, а имей сто друзей.
Reply With Quote
Old 06-15-2019, 04:59 PM
noelf noelf is offline
Join Date: Nov 2007
Location: Cary, N.C.
Posts: 1,177

Yes, what Vlad said.
Reply With Quote
Old 06-15-2019, 07:39 PM
jwilbur jwilbur is offline
Join Date: Dec 2010
Location: Culpeper, VA
Posts: 668

Thank you. I'll order new pads and o rings.
-Joe Wilbur (N520LW)
Phase II - 11/2017
First flight - 8/2017
RV-10 Build Log
Reply With Quote
Old 06-15-2019, 07:45 PM
BobTurner BobTurner is offline
Join Date: Dec 2011
Location: Livermore, CA
Posts: 6,156

Make sure you find the cause, donít just treat the symptom. The wheel pants should not be too hot to touch (the brakes, yes).
What is the white stuff around the threads?
Reply With Quote
Old 06-15-2019, 07:52 PM
jwilbur jwilbur is offline
Join Date: Dec 2010
Location: Culpeper, VA
Posts: 668

White stuff is loctite 567 thread sealant. I'm assuming it was hot from the long taxi with me riding the brakes too much and maybe some burning fluid ????
-Joe Wilbur (N520LW)
Phase II - 11/2017
First flight - 8/2017
RV-10 Build Log

Last edited by jwilbur : 06-15-2019 at 07:54 PM.
Reply With Quote
Old 06-16-2019, 07:00 AM
rleffler's Avatar
rleffler rleffler is offline
Join Date: Jun 2006
Location: Delaware, OH (KDLZ)
Posts: 4,156

If the wheel pant was too hot to touch, youíve got some other things to check. I had a similar experience when I had a stuck throttle and had to ride the brakes to slow taxi speed back to the hangar.

If things are getting that hot, there is a risk that some parts may warp. The key things to check are the rotor. Thatís easy to check on a flat surface, the other thing are the two sets of bushings. If not torqued properly and they get hot, the ends will flare. This will cause the floating pad to hang and potentially the caliper too.

I didnít check all the parts when I overheated the brakes that one time. Because of the additional friction that caused, the new pads pre-maturely failed. Itís been several years since that happened and they been fine since I replaced just about everything but the calipers.

My guess if you canít see where the fluid is coming from that itís most likely an o ring.

Because of the shipping delays from SLC to the east, I keep a set of parts to minimize downtime. I havenít had to use them, but itís good piece of mind.

I keep the next pad replacements, both sizes of bushings, o-rings, torx screws for the rotor attachment, and some or the nordlock washers.
Bob Leffler
N410BL - RV10 Flying
Reply With Quote
Old 06-16-2019, 07:06 AM
TS Flightlines TS Flightlines is online now
Join Date: Apr 2010
Location: Ridgeland, SC
Posts: 2,414

Joe, does look like a caliper piston O ring failure from the pic. Like everyone has said, keeping spare parts is a fabulous idea---especially Orings and such that for minimal expense can sure mess up your week--especially if youhave to order them from the vendor.

Tom Swearengen, TS Flightlines LLC, AS Flightlines
Joint Venture with Aircraft Specialty
Teflon Hose Assemblies for Experimentals
Proud Vendor for RV1, Donator to VAF
RV7 Tail Kit Completed, Fuse started-Pay as I go Plan
Ridgeland, SC,
Reply With Quote
Old 06-16-2019, 11:28 AM
JonJay's Avatar
JonJay JonJay is offline
Join Date: Jan 2007
Location: Battleground
Posts: 4,283

Switch to synthetic rubber o rings (Viton). They can handle the heat better, however, if it was so hot you couldnít touch the wheel pant, that is smoking hot and as others pointed out, everything will need to be inspected.
Smart People do Stupid things all the time. I know, I've seen me do'em.

RV6 - Builder/Flying
Bucker Jungmann
Fiat G.46 -(restoration in progress, if I have enough life left in me)
RV1 - Proud Pilot.
Reply With Quote
Old 06-24-2019, 11:05 AM
joe_rainbolt's Avatar
joe_rainbolt joe_rainbolt is offline
Join Date: Jul 2005
Location: Northern California
Posts: 88
Default Hot wheel pant

One note of caution on the hot wheel pant. On my last condition inspection, after reassembling the wheel pants, I allowed the brake line to be in contact with the inside of the wheel pant. The result was blistered paint on the pant and an unwanted new project for me. Going forward I will be checking that I have no point of contact between the brake line and the wheel pants.

Why was the brake line so hot? The issue occurred while bedding in new pads.
Joe Rainbolt
RV-7A slow build complete 4 July 2016
Visited all 48 contiguous states July 15-29 2017.

Reply With Quote

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

All times are GMT -6. The time now is 06:08 PM.

The VAFForums come to you courtesy Delta Romeo, LLC. By viewing and participating in them you agree to build your plane using standardized methods and practices and to fly it safely and in accordance with the laws governing the country you are located in.