[RV6AussieNick]

I'm looking at setting up my brake line setup, I have chosen a high burst pressure 1/4 OD nylon tube from Aircraft Spruce, I'm wondering what other builders have done to connect their brake line to -4 AN fittings at the master cylinder as well as bulkhead fittings. Aircraft Spruce doesn't have anything compatible for the brake line that can connect to AN fittings.
On the forward side of the firewall I'm using stainless steel flex hose to the brake calliper.

 

[Pop Alexandra]

Like! Can't wait to see what is the community consensus on this.

 

[mike newall]

Stick the tube in, nip up the nut until it strips, then back it off one flat

 

[snopercod]

Parker makes a whole series of brass compression fittings for that Nylo-Seal tubing. They also make brass inserts that you will want to slip inside the tubing end to keep the compression fitting from crushing the tubing. Many aircraft types that use the Nylo-Seal brake lines (Long-EZ for example) have had the fittings at the brake end come loose due to the high heat from the brake disc. For that reason, I chose to use Russell brake hoses for the last 18" of my brake lines, and the Nylo-Seal for the rest. Matco says the max pressure of their brake systems is 400 PSI and the working pressure of the Nylo-Seal and Russell hoses is well above that.

Here is how I adapted the Nylo-Seal to AN3 for my Russell brake lines down by the brakes:

The Parker fittings I used are on page G11 of this .pdf: https://www.parker.com/literature/F...ectors Group Static Files/G-BrassFittings.pdf

That .pdf also shows the 63PT Inserts I used (page G12). Be sure to buy the correct size for the wall thickness of the tubing you bought.

Be advised that Parker warns: "Compression Fittings are not for use on Air Brake applications" so, as always, you will have to evaluate these fittings and hoses yourself to determine if they are suitable for your use.

 

[az_gila]

If you are going to use a flexible "racing hose", why not simply use a full length (all the way up the hear leg) reinforced teflon hose and eliminate those non-standard couplings?

As always, there is a good VAF source - https://www.tsflightlines.com/

 

[TS Flightlines]

IF--

one were to have the 1/4OD, .190 ID nylaflo tubing, and ONE was a little creative, ONE 'could' use an AN hose end stem for teflon hose.
I say ONE 'could', because you 'can' but you'd need to make some retaining collars to make sure the fitting didnt come off the hose under pressure. 400 psi makes a pretty good mess, including the loss of brakes when you really need them.

So for all the trouble its worth, why not just use teflon hoses, or the Vans supplied nylon tubing 'system'?

Tom

 

[rvbuilder2002]

If you are going to use a flexible "racing hose", why not simply use a full length (all the way up the hear leg) reinforced teflon hose and eliminate those non-standard couplings?

As always, there is a good VAF source - https://www.tsflightlines.com/

One reason would be to avoid brake performance problems.
Not all hoses are equal.
Some hose has a higher level of expansion than others when under pressure.
If you have a lot of hose length it multiplys the amount of expansion that takes place.
There have been instances of brake problems (squeal, vibration, etc.) that were (with a lot of difficulty) eventually traced back to the use of long lengths of hose.
It is proven that in many instances long hoses also work fine. The problem is that not all do and there is no directory of the good and the bad to use for reference.

 

[snopercod]

If you are going to use a flexible "racing hose", why not simply use a full length (all the way up the hear leg) reinforced teflon hose and eliminate those non-standard couplings?

I'm not sure that was directed to me or someone else, but I did run the hoses up the full length of my gear (Mine are shorter than yours ). Those hoses I used are teflon/stainless with a vinyl outer covering to prevent stone damage to the SS braids. They're DOT-approved motorcycle brake hoses. I figure if they're good enough for a Harley, they're good enough for me

P.S. There's absolutely no reason for anyone to use 1/4" brake lines. The flow rate is minimal. In fact, many people are going to 1/8" lines these days. Saves weight, you know? I went with 3/16" lines.

 

[TS Flightlines]

"One reason would be to avoid brake performance problems.
Not all hoses are equal.
Some hose has a higher level of expansion than others when under pressure.
If you have a lot of hose length it multiplys the amount of expansion that takes place.
There have been instances of brake problems (squeal, vibration, etc.) that were (with a lot of difficulty) eventually traced back to the use of long lengths of hose.
It is proven that in many instances long hoses also work fine. The problem is that not all do and there is no directory of the good and the bad to use for reference."

Thats why using a good hose from a reputable company makes sense.

Tom

 

[rvbuilder2002]

"One reason would be to avoid brake performance problems.
Not all hoses are equal.
Some hose has a higher level of expansion than others when under pressure.
If you have a lot of hose length it multiplys the amount of expansion that takes place.
There have been instances of brake problems (squeal, vibration, etc.) that were (with a lot of difficulty) eventually traced back to the use of long lengths of hose.
It is proven that in many instances long hoses also work fine. The problem is that not all do and there is no directory of the good and the bad to use for reference."

Thats why using a good hose from a reputable company makes sense.

Tom

I guess it depends on what the definition of "good hose" is.
I have seen this problem with good quality hose that was purchased from a reputable company and rated for way higher pressure than what the system produces.
I guess what you could be meaning is that it is not good hose unless it was purchased from TS Flightlines

The point of my original post was that just because someone you know has had good results using long hoses, doesn't necessarily mean that you will.

 

[az_gila]

I guess it depends on what the definition of "good hose" is.
I have seen this problem with good quality hose that was purchased from a reputable company and rated for way higher pressure than what the system produces.
I guess what you could be meaning is that it is not good hose unless it was purchased from TS Flightlines

The point of my original post was that just because someone you know has had good results using long hoses, doesn't necessarily mean that you will.

IIRC the original RV-4s and -6s had nylo-seal tubing all the way down the gear legs.

Wouldn't good, heavy wall reinforced teflon tubing be better?

And yes, buy them from Tom S.

 

[TS Flightlines]

Scott--LOL---not meaning that at all, but thanks for the plug!
We've seen hose being filtered into supply chains that isnt quite up to par. Generally its a supposed conductive hose for fuel, but actually a black colored liner with out any carbon. Also, some of the braid isnt weaved as tight as 'reputable' spec hoses were.
YES, buying hose from major manufacturers is expensive. Titeflex (division of Smiths Aerospace), Parker, Eaton Aeroquip, Everflex, all make excellent, consistent hose. But, you can rest assured that the hose meets the specs that its designed for. Major 'performance plumbing' companies like Goodridge, Earls, Russell, and some others have excellent hose.

And as you know it may be a good hose, that wasnt assembled properly that created the problem, or the installation. Cant always fault the hose!

Tom