65C leaking right brake line

[JaredDavis]

Went to fly the plane and found a puddle of hydraulic fluid under the belly. As far as we can tell there is a leak in the line near a clamp point.

Has anyone had to replace a brake line in the belly? How long did it take?

It is part 850000-23 which just happens to be the longest line. Not sure if it can be replaced without bending it in place.

Any hints for the ap?

[N601RX]

When I added copilot brakes I had to form several of the tubes to fit. I ordered the aluminum tubing from Spruce in 6' pices and had to formed and flared to fit. Depending on where the leak is and the condition of rest of the tube it may be possible to cut out the bad inch or so, flare the ends and put a union in the middle.

[JaredDavis]

Thanks for the replies.

 

The lines may be original. It may be time.<g>

 

The break is not in an easy to access area.

 

The AP wanted to investigate a flexible hose solution vs Al tubing.   Any thoughts?  I was leaning towards the Al tubing as it worked for the first 50 years. But, I have no idea if it can be installed pre-bent which was his concern.  Flexible hose would go in easier but would have reduced clearances to push tubes.

[carusoam]

My 65 C got all of its rubber brake lines replaced after about 45 years...

The cherry juice brake fluid was harmful to their health. New materials are better suited for the job.

Doing it at annual was relatively painless. They are the low pressure return lines, not very high tech or expensive.

Hope that helps,

-a-

[N601RX]

A long length of flex hose might make the brake on that side feel softer due to slight expanding when under pressure.  Unless you have a 1 pc belly the area the brake lines run through isn't easily accessible.  There may be some additional access by removing the rear seat and through the inspection panels under the seat.

[JaredDavis]

Thanks.  What AL material and wall thickness is best?

[N601RX]

Here is what the copilot brake kit called for.  The older models use the tubing shown in item#1 and the later model J, K use what is shown it #5.

[JaredDavis]

Thanks again.

 

I don't see how one rigid line is going to fit.  Any issues using two relatively straight lines with a 90 elbow?

[N601RX]

Be aware that all aircraft flares are 37 deg not 45.  Based on 43.13 is seems like you could replace it in 2 pieces.

 

From AC43.13 

Repair of Metal Tube Lines. Minor dents and
scratches in tubing may be repaired. Scratches or nicks
not deeper than 10 percent of the wall thickness in
aluminum alloy tubing, that are not in the heel of a
bend, may be repaired by burnishing with hand tools.
Replace lines with severe die marks, seams, or splits in
the tube. Any crack or deformity in a flare is
unacceptable and cause for rejection. A dent less than
10 percent of the tube diameter is not objectionable
unless it is in the heel of a bend. A severely-damaged
line should be replaced; however, it may be repaired by
cutting out the damaged section and inserting a tube
section of the same size and material. Flare both ends
of the undamaged and replacement tube sections and
make the connection by using standard unions, sleeves,
and tube nuts. If the damaged portion is short enough,
omit the insert tube and repair by using one union and
two sets of connection fittings.