Hose life

[jimbo]

I cannot read the tag on my engine hoses because of their installed position so I'm asking the question here.

What is the service life for the oil cooler hoses (Vans VA-134, VA-1356) described as stainless flex hose and the Fuel supply hoses with firesleeve (Vans VA-129 & VA-138)? All these hoses are noted as AE701 hoses and it appears made from PTFE material.

What I read between the lines is that being teflon they are considered non-aging. Sure, you still have to use common sense as to condition and continued service but the hoses due not time out by themselves.

 

[Ironflight]

“Calling Doctor Tom, Doctor Tom, to the thread please!!”

I have spent years trying to get an answer on teflon hose life from the GUYS WHO MAKE THE HOSE! I ask them at Airventure whenever I think of it, and they all say “that’s up to the airframe manufacturer to set a calendar limit”…..

Well….WE’RE the airframe manufacturers, and I have no data on which to base a decision….

Paul

 

[jimbo]

I emailed Vans for a decision on this and they just directed me to see the tag on the hoses for the numbers. So no decision from them.

 

[TS Flightlines]

Jim--AE701 hose is NOT teflon, its is stainless braid, synthetic rubber liner. Aeroquip says life time, but we've seen them deteriorate from the additives in fuel in 7-8 years if service. Teflon is impervious to most all chemicals currently in use in aviation.

Tom

 

[JDeanda]

What I’ve Been Doing

Calendar life of a rubber hose is 7, 8, or 10 years, depending on who you’re reading. Teflon hoses are usually guaranteed for 7 years and I’ve always understood they’re good forever or until something happens to them like abrasion it overheating. Rule of thumb, if you’re really not sure go ahead, bite the bullet and replace them. Another thing you can do is remove the hose and lay it on the bench. If it stays the same shape, it’s done. Obviously, if you bend it and hear crinkly noises, it’s ‘way dead. Hoses are expensive but not as expensive as the damage they can cause when they fail.

 

[Canadian_JOY]

One thing that's quite important to consider...

If you have fuel and oil lines which are typical Aeroquip with firesleeve added after hose fabrication (firesleeve that's clamped in place with its own clamps) you will be VERY pleasantly surprised by both the flexibility of the new stainless/braided Teflon hoses AND their size. The outside diameter of the hoses being made by ASFlightlines is smaller than the diameter of a basic Aeroquip 303 hose without firesleeve. These new lines really make it far easier to route lines forward of the firewall and far easier to work on the engine once in place. Smaller lines give more space for hands!

Steve of the AS part of ASFlightlines made the hoses for our Sportsman. I was dead-set against the idea but my wife talked me into springing for the extra cost rather than me fabricating the lines myself. I have zero regrets - the lines were perfect right out of the box and Steve's level of support through the process was truly over the top.

 

[TS Flightlines]

Jerry and others, we've taken the position on rubber hoses of 8 years from the cure date of the hose for replacement. (navyaviation.tpub.com/14018/css/Age-Control-And-Service-Life-228.htm). Yes, its a military guideline, but in general terms applies to general aviation and experimental aviation as well. There was an old Lycoming guideline of 4 years of shelf life for rubber lined hoses.
To paraphase, to eliminate the short shelf life limits, Lycoming started using Teflon firesleeved assemblies. There was also a Lycoming SB #509 that was about the old AE601 hose (now 701 hose) that referred to the liner being adversely affected by additives in aviation fuel. In this SB, Lycoming states that, " teflon hose is normally unaffected by many of the operating variables that contribute to rubber hose degradation."

Be advised, that teflon hoses WILL take a set shape after many heat cycles. IF you were to remove and reinstall the same hose, support the hose in its shape as to not potentially fracture the hose liner. Chances are very good that you wont have a problem any way.

Tom

 

[jimbo]

Jim--AE701 hose is NOT teflon, its is stainless braid, synthetic rubber liner. Aeroquip says life time, but we've seen them deteriorate from the additives in fuel in 7-8 years if service. Teflon is impervious to most all chemicals currently in use in aviation.

Tom

The plans show AE-701 hose for oil cooler and fuel supply. If you go to Vans website store they list these hoses as "Conductive PTFE intregral firesleeve hose". So I'm understanding PTFE to be teflon. Granted what Van is selling on gtheir website today may not be the same hose as what they were selling 10 years ago.

So Teflon or not? Confusion abounds.

 

[TS Flightlines]

Jim----YES the plans show AE701, but the plans have NOT be updated. The VA*** part numbers originally shown in the plans are now VA***-1---the -1 indentifies it as an integral firesleeved hose assembly, that we build for Vans.
Examples shown here---I dont think that Paul will mind----The old 701 hoses with the AS1072 firesleeve on top, our integral teflon firesleeve assemblies on the bottom---the same hose now in the VANS FWF hose package. Same original lengths and configurations, but upgraded to integral teflon.

Tom

 

[AlpineYoda]

Do what all the smartest, best-looking, and most talented builders do, and just buy a full set of fire sleeved, lifetime hoses from Tom. Look how helpful he is already, and you aren't even a customer yet.

 

[TS Flightlines]

Another good reason to look around when the cowling is off.
Pretty self explanatory.

Tom