Brake line choice

[patrickh99]

Is anyone using nylon brake lines or some other form of synthetic line?
Any pros or cons from experience?

[marcusofcotton]

I wouldn't have them at the caliper due to possible heating troubles.

[tailwind]

Full nylon lines with about 100 hrs on this plane. No problems to date. I ran them on another plane without problems also. I have DOT approved automotive quick connectors at the connections. I like them because I can see air in the lines during the initial fill of the system and I can monitor the brake fluid level from my seat when doing a preflight check. Never have had to add fluid to my system since it was charged.

[whee]

When I was researching for my brake system I found several references that indicated in situations when heavy braking will be frequently required (STOL ops or bush wheels) that a hard line should be used. It was something about the synthetic line expanding under high pressures causing a spongy feeling and a loss of braking power. I don't know if that is true but I don't want to redo my brake lines if it is so I'm going to use hard line where possible.

[AZBearhawk272]

I recommend not using the nylaflow or similar tubing type products. This tubing is generally
Problematic for brake applications creating leaks, air entrainment, tubing compliance,
Soft pedal etc. N 509RF previously had nylon
Tube replaced with Parker high pressure -3
Flexible brake hose for sprint and race car
Applications. Perfect performance.
Never a leak. Rock solid pedals.
Expensive but very well worth the cost.
Lesson learned the hard way. Nuff said.

Kevin D. 509 CMO / 272 perpetual builder

[tailwind]

Sport Aviation April has a short reference to nylon brake lines, on page 28. Experimenter hints for home builders.

[patrickh99]

Thanks for the feedback. Sounds like results vary.

@ Tailwind & Kevin: What brand of nylon hoses did you use?

[tailwind]

I used nylaflow tube rated at 1000 psi in aircraft spruce catalog. To assemble the system I used DOT approved brass Parker "push to connect" fittings from MSC or McMaster Carr

[Battson]

I used nylaflow tube rated at 1000 psi in aircraft spruce catalog. To assemble the system I used DOT approved brass Parker "push to connect" fittings from MSC or McMaster Carr

I used the same parts as you, Nylaflow and Brass, inside of the firewall and around where the hoses need to flex. Then I used aluminium line from the parking brake valve onwards.

Do NOT use the Nylaflow connectors, they are complete junk. I tested them.

The Nylaflow hose itself is very, very stiff. I would be surprised if it's dimensionally flexible enough to cause a spongy feel in the brakes. It comes in a thick-walled version too, if you were concerned about a spongy feel.

Be sure to put that reservoir on the forward side of the firewall, they can leak our the breather cap and that stuff is nasty. Obviously you need to use aluminium line firewall-forward.

[tailwind]

I have the reservoir mounted high on the engine side of the firewall with a steel line passing through the fire wall. Since my lines from the firewall pass through are nylaflow I can see the fluid in the lines from my seat. I have made the decision not to keep fluid in the reservoir but to monitor the level of fluid in the lines. This way I can see a fluid change as soon as it occurs. I have never seen a fluid level change since I built the system. I am also using automatic transmission fluid as my brake fluid. It has very similar specifications to 5606. This way I don't need to keep another product on my shelf and I can purchase it locally.

[Zzz]

I'm using Aeroquip -3 stainless braided teflon hose. A friend who is a very proven and capable "big rocks long props" type of guy uses it from caliper to master cylinder, no hard line. Few brake as hard as he does (on 35's) and he claims he gets no braking pressure loss. This is how I've planned to route mine as well.

As for the little routing I'll have on the firewall for my Grove remote reservoir, that'll likely be 3/16 5052 aluminum.

I suspect the OP is asking about unsheathed nylon hose?

[patrickh99]

Yes, I was asking about unsheathed nylon, or variations thereof. I have seen it used in a variety of EABs and have heard many conflicting reports, from "It shatters once aged" to "Best thing ever". Airbrake hose has also been highly recommended. I am leaning towards following Battson's strategy in #9

[Blackrock]

A very good mechanic friend used to swear by the Nylaflow stuff as he flew with it for years. Then it failed and nearly cost him the plane. You can't run fast enough to give it to him now. I have heard other similar stories from people I trust. It works for a while and then it doesn't. I used both hardline and the hose Zzz speaks of. That hose is great and if I were redoing my lines, I'd use that entirely.

[Battson]

Let's not forget that all the common brake line materials and designs fail too. Just looking inside NZ, I can think of a half dozen planes which have been badly damaged in the last few years, due to brake system failures of various descriptions, most with the "old school" materials.

Nylaflow isn't a bad choice because it fails eventually. Everything fails unless your maintenance and inspection regime is preventing failures, that's a fact.

[John Bickham]

Zane,

I'm approaching the plumbing phase on my project. I've had good success with nylaflow brake lines in my previous plane. It was pretty light, but crossed the Rockies four times(some around). For a Louisiana flatlander, that was kinda a big challenge. Anyway, I'm considering your approach with the Aeroquip-3 SS braided TFE hose. This will be another first for me and have some noobie questions.

Was that Aeroquip AQP hose?

Finding -4 but not seeing -3 size? Old fart trying to use internet probably. Could you steer me toward the best source?

Did you get speicific pre-made lengths or did you buy a length and make up the fittings yourself??