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hoses 5 yr changeout

dick seiders

Well Known Member
Would appreciate if someone out there would provide info on the topic that is brief, concise, and complete. Call it a hose change info kit if you will. If one is created it will save all of us at the 5 yr change , and those down the road a ton of research. for ex:

Oil hoses are vans supplied and good for 10 yrs.
Fuel line hoses are Rotax? Are they supplied by Vans, Rotax, and how do they compare to alternative teflon stainless hose fplks and what is the approx. diff in cost?
Engine water coolant hoses I presume are Rotax supplied?
Radiator coolant hoses come from where? There are no VA nos so not Van's?
Hose removal tool from Amazon should be part of this as well.
Any other necessary info as well.

I would certainly appreciate a primer on this and I suspect the many who are coming up on it would as well. Many thanks.
dick seiders 120093
 
Hi MMiller,

I believe the 81mm comp tube is part 956-391. Is this the number you eventually got?
The old part number used to be 956-141.

The 66mm tube is 956-143.
 
MMiller,

Many thanks for the spreadsheet with the necessary info to make the change-out of the hoses. As I work my way thru the conversion I will post any unexpected issues if they arise. Your efforts have saved a bunch of flyers a lot of unnecessary hunting and grinding it out. I don't see how having to do that that makes any sense when the info has already been acquired and shared by forward thinkers like you.
Thanks again.
dick seiders 120093
 
I believe that Rotax requires all rubber components on the engine to be replaced every 5 years in their maintenance manual - but with an experimental aircraft that is only for info. Teflon hoses have no life according to Aeroquip, so replacing the rubber fuel & oil hose with 666 hose (or similar) is worthwhile although expensive. Silicone coolant hoses (typically blue) have a similar long life. If you have a oil thermostat the hose list is significantly different.
 
M Miller, Leaf no longer offering the 11mm dia hose part no 956141 now supplying the 956143 in it's place. No one Leaf, CPS, or Lockwood is offering any 11mm hose. I suppose the Rotax people think the 12mm is close enough?

Second question is your list shows 874911 carb fuel line from Rotax. I am under the impression all fuel lines are to be replaced with 10 year Teflon lined hose like by someone like TSF for example?

Third question is why does VA216 show up as 10 year hose? I was under the impression that Van's 10 year lines as originally supplied were oil lines only?

appreciate your feedback. Thanks.
dick seiders 120093
 
Vans 'may' have changed the VA216 to teflon; not sure about that, since we make all of ours from teflon.
Tom
 
Tom,
Maybe, but I just looked at the plans and a change to TSF fuel system requires these lines be replaced anyway as they have banjo fittings and won't fit the new setup.
dick seiders
 
When we designed the Rotax package for the RV12, we took in consideration all the fuel hoses. Thats why we made it a package.
Tom
 
Seems like a lot of over-thinking. 11mm is 1/2". I haven't done the numbers, but I recall the ROTAX course instructor saying the coolant hoses are 5/8". Why not just go to Auto Zone and buy replacement hose if you are an ELSA?
 
13mm is 1/2" which is what most use on the oil hoses. Each Rotax service center uses a different hose for the 13mm (1/2") oil hose. The large coolant hoses are 25mm (1") and the Rotax supplied coolant hoses are 17mm of which there is no good substitute in US hose size and only one company in the US even makes the hose and only for Rotax.

11mm = .43"
12mm = .47"
13mm = .51" oil hose

When buying oil hose you need to make sure it is rated for high temp and pressure.
Fuel hose needs be be rated for ethanol which almost all fuel hose is any more.
Coolant hose can have different temp specs so make sure you review those specs before buying. Gates (Green Stripe) and Dayco do make some acceptable 1" coolant hose.
Gates Barricade hose for fuel is good hose and is well rated for any ethanol use. Wurth fuel hose is another good hose.

I believe Lockwood sells Aeroquip hose for fuel and oil and CPS sells Parker hose for the oil.
 
IMO the coolant hoses are the most vulnerable of the Rotax hoses. They are fairly close to the exhaust pipes and are not sleeved. I think it would be prudent to use the best quality and best fitting hoses we can find and I also think 5 years is an appropriate life cycle. Regarding oil hoses, I am comfortable stretching the change intervals. I am not advocating 15 or 20 years, but I am comfortable with 10. If fuel hoses are Teflon, I am comfortable with 10 also.
 
Many tell me in class that they put heat shielding on the coolant hoses that are close to the hot exhaust. You can either take some fire sleeve (3"-5") and split it up the middle or buy some regular fire insulation and wrap either around the affected area. This will help considerably. Over the years I have seen too many oil and coolant hose burnt through inflight because the hoses were touching hot exhaust pipes. Burn a coolant hose through and you can still have reduced power for up to 30 minutes. Burn an oil hose through and you most likely bought a new engine.

p.s.
I have also seen several oil hoses in fire sleeve that had touched the hot exhaust and there was a small amount of damage to the outside of the fire sleeve and the inner oil hose got burned through. You really can't inspect fuel or oil hose in fire sleeve unless they are removed.
 
Many tell me in class that they put heat shielding on the coolant hoses that are close to the hot exhaust. You can either take some fire sleeve (3"-5") and split it up the middle or buy some regular fire insulation and wrap either around the affected area. This will help considerably. Over the years I have seen too many oil and coolant hose burnt through inflight because the hoses were touching hot exhaust pipes. Burn a coolant hose through and you can still have reduced power for up to 30 minutes. Burn an oil hose through and you most likely bought a new engine.

p.s.
I have also seen several oil hoses in fire sleeve that had touched the hot exhaust and there was a small amount of damage to the outside of the fire sleeve and the inner oil hose got burned through. You really can't inspect fuel or oil hose in fire sleeve unless they are removed.

Roger, give us a number for how many is "too many" hoses that got burned through. Did these get reported to the FAA?

When you say "I have seen", do you mean you saw them personally? Was this in engines that you worked on, examples held up in class, pictures in a book? I'm trying to get an understanding of the number of these instances. These would seem to me to be so serious that we'd all have seen a lot of information about them if this problem was endemic.

Or is this an expression of "one is too many" and the actual number to your own personal knowledge may be one or two?

If any of these resulted in an accident report, maybe you could pass on the information and wew could research further.
 
I don't know how many Roger has seen, but I check my hoses regularly. My buddy, who was building at the same time as me had a problem. When he did his 25 hour oil change, he found the oil cooler hose, VA-214 that makes a tight turn at the right front of the engine was almost burned through. He replaced the line, and I think that he even shortened the little standoff strap. I saw the hose, and it was a bit scary.............tom
 
FWIW

I too was concerned about how close that particular hose was to the exhaust pipe and wrapped some heat shield material around the fire sleeve where it was close to the pipe. I used stainless tie wraps to secure the heat shield material.

I ordered this silver colored asbestos material from one of the aftermarket providers of stuff for RV's and so far so good. It seems to protect this section of oil line and it has always been on so I don't know any other condition since it was never exposed.
 
Patrick, do you mean asbestos looking material or is it really asbestos? if so get rid of it. The fibers in asbestos are lethal, and it's no longer environmentally legal to use it. Since about 1978 I think.
dick seiders 120093
 
MMiller, Lockwood no longer supplies the 956143, nor the 956141 11mm hose. They sell 956140 (11mm) for both of the old numbers. It comes in bulk but they'll sell you enough for the two lengths required for about $17.
All your other hose info was right on. Thanks.
BTW, Leaf says they don't have any?? So Lockwood is the place to go for those needing them.
dick seiders 120093


Oops! that was in your post, but they will sell half of the length you mentioned for the $17.
 
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Probably over-thinking, but...

Pre-planning the 5-year ordeal... Got my order in to TS Flightlines for the fuel and oil hose assemblies. Looking at the Lockwood 5-year parts list for the cooling system wondering how well the larger diameter hose negotiates the bends. They show it as 25.4mm, i.d., I presume.

I could be wrong but the person I spoke to at Lockwood did not seem to be aware of RV-12 differentiation from other 912 configurations and assured me the parts list was all I needed.

What has been the experience among the 100 or so RV-12's certified before mine regarding the applicability of the aforementioned hose? Also, are y'all re-using the original clamps or retrofitting with conventional clamps?

TIA
Jim
#264 flying since 12/10
 
Pre-planning the 5-year ordeal... Got my order in to TS Flightlines for the fuel and oil hose assemblies. Looking at the Lockwood 5-year parts list for the cooling system wondering how well the larger diameter hose negotiates the bends. They show it as 25.4mm, i.d., I presume.

I could be wrong but the person I spoke to at Lockwood did not seem to be aware of RV-12 differentiation from other 912 configurations and assured me the parts list was all I needed.

What has been the experience among the 100 or so RV-12's certified before mine regarding the applicability of the aforementioned hose? Also, are y'all re-using the original clamps or retrofitting with conventional clamps?

TIA
Jim
#264 flying since 12/10

I can't comment on the applicability of the Lockwood kit, but the spring clamps are used for a very specific reason, so I recommend not substituting screw clamps.
 
Would appreciate if someone out there would provide info on the topic that is brief, concise, and complete. Call it a hose change info kit if you will.

I would certainly appreciate a primer on this and I suspect the many who are coming up on it would as well. Many thanks.
dick seiders 120093

Dick, have you completed your hose replacement project. If so, can you summarize the parts purchased, where purchased, tools needed, problems encountered, etc. Sure would like to see your final report. Thanks!

Any others that have completed this project.... sure would like to see your report as well.
 
Mine is done

I ordered the hoses listed by someone on the forum a while back from Lockwood without looking too closely-- some of them are oil hoses with a VAF number that don't need to be replaced until 10years-- just inspected each C.I. So I have the hoses to do the oil lines in 5 years if I can remember where I put them.

Removing/replacing big coolant hoses was no problem-- be sure to use the hose removal tool mentioned earlier. The big hose with the sharp bend is the one we put the spring inside of when installing it 5 years ago. Spring comes out easier than it went in.

Short coolant hoses from the reservoir to the heads are a B(*&*(^&%&^$! MY problem was that some were situated so that I couldn't get a pair of hose pliers on them, and I had every type known to man. Took two of us to get one hose off. Put new ones on so that clamps are accessible if I'm still alive five years from now.

Took the better part of two days but was easier because the nosewheel strut was off.

I had a Rotax-trained A&P do the carb rubber replacement earlier this year.

Wayne 120241/143WM Still waiting (5 WEEKS!) for prop blades, Yes, they were supposed to be shipped "This week" which was last week, Nov. 30. Wish I'd known-- I'm sure I could have traded props with someone who won't be installing theirs for a while. Two weeks of really nice weather (for Dec. in Ohio) with no prop.
 
Spring clamps

What's the specific reason for using spring clamps? My mechanic favours srew type clamps "because you can nip them up".
 
Spring clamps are used in many places in industry where pressures are low and piping or tubing may expand and contract. This is done because of thermal expansion and contraction. The spring clamps used on the Rotax are used where the hose is on aluminum tubing. I would stick with the spring clamps. Just a side note. When taking these off or putting them on make sure you do not damage them with a tool you are using. They do make a cable tool that is made for these types clamps. I have seen some use pliers and that in itself won't damage them, but if you twist and smash them it will. This will cause them to become a loose fit and could come off.

A note on screw clamps.
Do not use the serrated hose clamp that comes from a hardware store that many use on garden hose. It can over cam and become loose, it cuts into the outside of the hose and does not provide a good 360 degree seal.

If you are going to use a screw clamp in an application on this engine either use a fuel injection clamp or a Wurth (raised rip) style screw clamp.
Do not over tighten clamps especially on brass barbed fittings or they will cut into the inner liner of the hose. Over tightening will also cause hose cracking over a short time under and around the clamped area.


Owners get in trouble with Rotax engines because they or an A&P wants to do things they do on Cont. & Lycomings or their lawnmower. Rotax does many things for reasons not posted and from many years of research, testing and modifying. It's always best just to put it back the way you found it. Even some aircraft Mfg's have made modifications to the engine through the years and some haven't worked out so well.
 
Hi Yankee-Flyer,

When working to remove or replace the spring clamps under the air intake areas it is easier to just remove the 4 screws on each air intake manifold and this will allow you to lift up and move things out of the way to get at these couple of clamps.
On the bottom of the engine it is many times easier to remove the muffler and this will allow ample access to hose under or around the bottom of the engine.
 
Pics

Hose tools -- Available from Rotax suppliers and others:
i-zHhK2SK-M.jpg


Intake pipes removed for access to top rear hoses--you may want to have new O-rings on hand:
i-3Z8x3nw-M.jpg

i-722fdrF-M.jpg


Muffler removed for better hose clamp access:
i-m2JFpVh-M.jpg

i-ZwJPht9-M.jpg
 
You DEFINITELY want the muffler off.

I was doing this during the C.I. so the muffler was off. My problem with some hose clamps is that when I took the "spider" off to install the engine baffle I wasn't thinking about having to get to those clamps on 5 years and some of the earls were positioned such that I couldn't get a tool on them.

Wayne 143WM-- yes, STILL waiting on prop blades. Have now been told for the 3rd week in a row "they'll be shipped next week".
 
Quick Question

Just got my coolant hose replacement kit from Lockwood. There's a pricy ($53) 90 degree water tube PN 922-192 included. I can't remember seeing this on the engine and can't find it in the catalog schematic. Another 12 builder can't find it in the Van's plans.

I noticed, however, it was on the Rubber Replacement List posted on the Forum...

Could somebody save me a de-cowling trip to the airport (low clouds today) and tell me if this is, indeed, part of the RV-12 912ULS configuration and not a generic Rotax item.

TIA, Jim
 
Yes it is

It connects the reservoir to one of the engine coolant tubes. If you look at the tubes you will see that one is smooth rubber (that's the molded one) while the others have a much rougher texture. You'll cut those from a length of hose in the kit. Get every type of hose clamp plier known to man before you start.

Wayne 120241/143WM
 
The 17mm hose on top of the engine and the two on each underside of the cylinders is made for Rotax by just one company. Unfortunately this hose has no US equivalent. I have seen some try and use use US hose sizes on this and it usually hasn't turn out well. It is a little pricey, but I would stay with it. It is sold by the meter and usually 2 meters is enough. The constant compression spring clamps are to be used with this hose 17mm only. These spring clamps will expand and contract with the heating and cooling of the aluminum fittings the hose is over. The rubber hose settles over time and it's OD can shrink just enough to leak with worm drive clamps.
The one 17mm hose on top is indeed a 90 degree preformed hose.

When replacing these hoses on top it is much easier to remove the 4 screws on each air intake manifold to allow easy access to the 90 degree fittings the hoses are on and it allows easier replacement of the hose on the expansion tank too. Don't drop anything down inside the air intake openings. I would cover them and use a flashlight to double check before putting the screws back in place. The screw torque is 90 in/lbs.


I hope this helps?
 
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Mr. Sink...

Yessir, it does help. Any other tips you can share would be most appreciated. In particular, suggestions on order of disassembly for the hose changeout process and carb re-build tips.

Jim
5 years up this month
 
Has anybody tried silicon automotive heater hose? At the ROTAX course the instructor said he has seen EAB engines with 5/8" heater hose and no issues. I know many don't like using non-aeronautical parts, but this would seem to be an application where the automotive and aeronautical environment are the same. Of course the consequences of failure are quite different, but the auto operating history seems to indicate automotive hoses are just as durable as the ROTAX hoses.
 
I know some don't want to hear this, but
Sometimes it's just better to stick with the proper parts and not try and save a few bucks. If you blew a hose off in flight saving $100 could cost $16.5K if you fry the engine. The least it may cost is $1.5K to get all the heads hardness tested plus the labor.
Flying = $$$ and cutting some corners can be 10-1000 times more costly in the long run.


5/8" hose will not even come close to fitting. 5/8" = 15.87mm. It won't stretch and if you forced it on you would weaken and break any internal fibers of the hose at the fitting. The spring clamps would then be too big. Anything other than the 17mm hose and the spring clamps would be useless.

11/16" = 17.46 mm
This is too big and the spring clamps absolutely won't work and the hose would leak. Then owners want to use worm drive clamps because they are cheap and you can get them from the hardware store.

If owners need to use a worm drive style clamp on a hose use a good Wurth Zebra raised rip wormdrive clamp. It doesn't cut into the hose and it won't over cam and slip. They are not costly.

If you own an SLSA in the US you can't use other clamps and hoses without Vans approval. I doubt that would be forthcoming due to the liability.
 
Joe,

I understand your position, but it doesn't answer the question. Has anybody tried an alternative, and if so what was their experience with it?

Rich
 
silcon hose

I used silicon hoses from a truck supply 5/8 and 1" they fitted fine I used a bit longer hose where the original 90 degree bend was I also replaced most of the hose clamps with "otiker " single ear clamps on the 5/8 hoses and reused the original clamps on the 1" hoses The springs were transferred to the new hoses I had no leaks and have 10 hours on the new hoses
I used aviation hose to replace the 1/4" fuel lines and fuel injection hose for the 5/16" lines the local hydraulic shop swaged the removable hoses and I used the otiker style clamps on the other ones
 
Thanks, Ashley. That's the info I wanted. A lot of folks think there is something magic about OEM parts and everything else is inferior. I think EXPERIMENTAL means experimental and we should exercise the latitude given us by law with prudence.

Rich
 
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