Any idea where you can get the 1/4" OD .062 wall nylon tubing Van's uses for brake lines? I can find thinner wall tubing, but not .062. I could order 9 feet of it for $30 plus shipping from Van's, but I'd rather find it locally if I can figure out what kind of place might sell it. Google hasn't been much help. Worse case scenario, I'll just order from Van's, but was hoping to find something I could just grab locally or order by the foot since I only need a 3-4'. I made the mistake of cutting my brake line that goes from the right to left side about an inch too short, so it pulls with full rudder deflection (at least I assume - at this stage I don't actually know what "full" deflection will be - is it an inch or six?).
Van's Air Force
Don't miss anything! Register now for full access to the definitive RV support community.
Nylon Brake Tubing - Source?
- Thread starter skelrad
- Start date
RVbySDI
Well Known Member
Maybe that has been your experience, and no question that your comment is spot on with TS Flightlines. They are top notch people. Tom is one of the best. You will never go wrong buying any products from them.
However, here is a data point to contemplate. I have been flying my 9A for just under 14 years and 900 hours now with the Vans supplied plastic brake lines the original poster is asking about with no leaks in all that time.
Freakshow108
Well Known Member
Tubing
PM sent. But I second TS. I used their products in place of the Vans supplied lines and love them.
PM sent. But I second TS. I used their products in place of the Vans supplied lines and love them.
PaulvS
Well Known Member
Aircraft Spruce
Is it critical that the wall be .062, versus the pressure rating being adequate? Aircraft Spruce sells 1/4" OD wall thickness .050 with a bursting pressure above 2000 PSI, two brands, available by the foot. e.g.
https://www.aircraftspruce.com/catalog/pnpages/05-04349.php
https://www.aircraftspruce.com/catalog/pnpages/05-12488.php
This is what I used after discovering that I cut the Van's tubing too short and just ordered more along with some other parts I needed from ACS.
Is it critical that the wall be .062, versus the pressure rating being adequate? Aircraft Spruce sells 1/4" OD wall thickness .050 with a bursting pressure above 2000 PSI, two brands, available by the foot. e.g.
https://www.aircraftspruce.com/catalog/pnpages/05-04349.php
https://www.aircraftspruce.com/catalog/pnpages/05-12488.php
This is what I used after discovering that I cut the Van's tubing too short and just ordered more along with some other parts I needed from ACS.
The lines do have a tendency to weep. On the pressure side I blew a tiny pin hole on the left side of my RV4 at around 800 TT just after I bought it. Good thing it happened during run up and not roll out as it could have been catastrophic. I grounded the plane and had some hydraulic lines made and replaced them all.
Tim
Tim
Fair enough, I shouldn't have implied the generalization in my OP. In fact, the RV-7 that I built 20+ years ago still has the nylon lines and they aren't leaking to my knowledge.
PaulvS
Well Known Member
Our club RV has the nylon lines and they are fine. The SAE brass fittings work well and need to have the small brass inserts fitted in the bores of the tubing.
I'm sure the braided stainless hoses would be great too, but more expensive, heavier and also opaque so you cannot see if there are air bubbles or fluid in the lines.
If there was a problem with the nylon lines then surely Van's wouldn't supply them as standard?
Stevea
Well Known Member
The nylon tubing with the brass insert works fine on the low pressure side of the brake master cylinders (between the master cylinder and the reservoir). I did not use it on the high pressure side (master cylinder to caliper). Used aluminum tubing on the high pressure side. (Done in the days prior to TS Flightlines hoses.)
Special Delivery
Well Known Member
Search Parflex N-4-062. Max O/P=500# Min Burst=2000#
Lots of sources
Lots of sources
Last edited:
Brandon,
With all the folks here using TS Flightlines, my guess is that there is an abundance of PEX brake line laying around on shelves. It's very inexpensive and I'm not sure what anybody would do with it if they've gone the TS Flightlines route.
Like so many others I used TS Flightlines so I have the brake line that came with my kit sitting on the shelf. I'm assuming it's what you're looking for. If you want to PM me your address, I'll send it to you.
If you want to send me a few bucks in return for shipping once you get it, that would be great. If not...well, that's your call.
Fred
With all the folks here using TS Flightlines, my guess is that there is an abundance of PEX brake line laying around on shelves. It's very inexpensive and I'm not sure what anybody would do with it if they've gone the TS Flightlines route.
Like so many others I used TS Flightlines so I have the brake line that came with my kit sitting on the shelf. I'm assuming it's what you're looking for. If you want to PM me your address, I'll send it to you.
If you want to send me a few bucks in return for shipping once you get it, that would be great. If not...well, that's your call.
Fred
Scott Hersha
Well Known Member
Nylon lines on the low pressure (gravity feed from reservoir) has worked for me with no leaks on all 4 RV’s I’ve built. It’s important to make sure the brass insert is pressed in all the way until it bottoms out on the end of the tubing, and that the tubing is cut square with a sharp tubing cutter. It can take considerable force to push that brass insert in all the way. On mine I pushed it in on assembly (nut and ferrule on first) against the edge of my work bench with a lot of weight behind it. All of my pressure lines came from TS Flightlines, like others here.
same here. When installed correctly, they do NOT leak. That includes the thick walled stuff that is under several hundred PSI.
wawrzynskivp
Well Known Member
Swamp Cooler Hose?
Bit of a post drift but since people are opining....
I listened to a certified FAA repairman explain that the plastic hose seen in many RV brake system is actually swamp cooler hose. No sense arguing that mindset but it explains the prejudice.
I used the 2000psi burst pressure nylon hose on both the feed and the pressure side, and intentionally tried to pop it or cause a leak. Math: Using an arm of 2:1 for the relationship between center of the brake pedal to the pedal fulcrum arm and the arm of the master cylinder push rod to the fulcrum, and assuming a -012 buna o-ring on the piston means the bore of the master cylinder is 1/2", and ignoring frictional losses, we would need to apply 196 some odd lbs to a single pedal to meet the burst spec of the line. That's a combined leg press of 392 lbs! I don't know if I am up to that anymore. I didn't measure the force I was applying but I would guess at around 60 lbs on each pedal I felt something begin to yield and pushed no further. What was yielding? Who knows. My guess is that I was 100 psi over working pressure for the hose so I was probably in elastic deformation. (hose swell but not permanently deforming)
No leaks, no bulges, no visible result of a crazy amount of brake pressure that would only serve to lock up the wheels in actual use.
So I stayed with the nylon stuff inside the cockpit and used the metal braid shielded stuff outside the cockpit for the sake of abrasion/fire toughness. Inside I used plastic spiral wrap to ensure nothing chafed. In 5 years I haven't come to regret that.
Bit of a post drift but since people are opining....
I listened to a certified FAA repairman explain that the plastic hose seen in many RV brake system is actually swamp cooler hose. No sense arguing that mindset but it explains the prejudice.
I used the 2000psi burst pressure nylon hose on both the feed and the pressure side, and intentionally tried to pop it or cause a leak. Math: Using an arm of 2:1 for the relationship between center of the brake pedal to the pedal fulcrum arm and the arm of the master cylinder push rod to the fulcrum, and assuming a -012 buna o-ring on the piston means the bore of the master cylinder is 1/2", and ignoring frictional losses, we would need to apply 196 some odd lbs to a single pedal to meet the burst spec of the line. That's a combined leg press of 392 lbs! I don't know if I am up to that anymore. I didn't measure the force I was applying but I would guess at around 60 lbs on each pedal I felt something begin to yield and pushed no further. What was yielding? Who knows. My guess is that I was 100 psi over working pressure for the hose so I was probably in elastic deformation. (hose swell but not permanently deforming)
No leaks, no bulges, no visible result of a crazy amount of brake pressure that would only serve to lock up the wheels in actual use.
So I stayed with the nylon stuff inside the cockpit and used the metal braid shielded stuff outside the cockpit for the sake of abrasion/fire toughness. Inside I used plastic spiral wrap to ensure nothing chafed. In 5 years I haven't come to regret that.
We keep seeing "when properly installed". Well, yeah, agree, but.
The probability of long term leak free installation is far higher when using pre-made hoses with AN flare fittings. Note it's pretty much the same tubing, but with the addition of flare fittings, machine crimped ferrules, and steel braid protection.
The probability of long term leak free installation is far higher when using pre-made hoses with AN flare fittings. Note it's pretty much the same tubing, but with the addition of flare fittings, machine crimped ferrules, and steel braid protection.
Still requires correct installation, though I agree you must put in considerably more effort to get the AN fittings installed incorrectly and leak. Was only trying to make the point that we shouldn't blame the parts just because some people have problems with them due to incorrect installation. I have seen leaks on AN fittings during prebuys, so they are not necessarily immune from installation error either. Most of the leaks that I have seen on brake lines are from the NPT portion of the fitting not being tightened enough.
Last edited:
Firesleeve
After having read the threads about the nylon hoses going soft and leaking because of heat from the brake assemblies I put firesleeve (that I anyway had laying around) on the first 12" or so from the 90 deg elbow on the brake cylinder and loop to the gear leg on my RV-4.
Finn
After having read the threads about the nylon hoses going soft and leaking because of heat from the brake assemblies I put firesleeve (that I anyway had laying around) on the first 12" or so from the 90 deg elbow on the brake cylinder and loop to the gear leg on my RV-4.
Finn
Three decades or 30-years ago, the flying RV's that used the recommended "Nylo-Seal" (that was name it was marketed under back then), would soften on long taxis and break / leak just when the brakes where needed.
Van's changed from it to the solid aluminum lines on the RV-6 shortly there after. Had many friends with flying RV-4s have issues and eventually changed out and away from using the high pressure nylon tubing on the high pressure side of their brakes.
Van's changed from it to the solid aluminum lines on the RV-6 shortly there after. Had many friends with flying RV-4s have issues and eventually changed out and away from using the high pressure nylon tubing on the high pressure side of their brakes.
Van's changed from it to the solid aluminum lines on the RV-6 shortly there after. Had many friends with flying RV-4s have issues and eventually changed out and away from using the high pressure nylon tubing on the high pressure side of their brakes.[/QUOTE]
I had bought a well built RV4 from a well recognized builder so no doubt in my mind that mine was built to spec or better at the time.
There are several posts in the forum about the occasional failure of those plastic lines. I was fortunate that mine failed during run up and not during landing. It only made sense to upgrade to something stronger to ensure it didn't happen again.
Tim
I had bought a well built RV4 from a well recognized builder so no doubt in my mind that mine was built to spec or better at the time.
There are several posts in the forum about the occasional failure of those plastic lines. I was fortunate that mine failed during run up and not during landing. It only made sense to upgrade to something stronger to ensure it didn't happen again.
Tim
There are several other manufacturers that use nylon tubes at the calipers, or near the brake rotors. This is a higher heat area, and probably should not have a hose there. WE try to avoid exposure as much as possible. Yes even stainless braid teflon thats rated to 500* can fail if you get enough prolonged brake heat.
Long taxis, hard braking after landing, fires, etc, can all damage a hose. Doesnt matter what the material is. Even the hard lines can be damaged.
As for the nylon hose and brass fittings, as we all have seen there are alot of vintage RVs and others flying with nylon hoses. Its all in the assembly, and the care you use when braking. Easy on the brakes and limiting the high pressure cycles certainly will increase the life, and keep leaks to a minimum. BUT, we developed our braided teflon packages for those that wanted a tested assembly for their plans.
Tom
Long taxis, hard braking after landing, fires, etc, can all damage a hose. Doesnt matter what the material is. Even the hard lines can be damaged.
As for the nylon hose and brass fittings, as we all have seen there are alot of vintage RVs and others flying with nylon hoses. Its all in the assembly, and the care you use when braking. Easy on the brakes and limiting the high pressure cycles certainly will increase the life, and keep leaks to a minimum. BUT, we developed our braided teflon packages for those that wanted a tested assembly for their plans.
Tom
