Exhaust spring replacement

H. Paul Shuch is a Light Sport Repairman with Maintenance ratings for airplanes, gliders, weight shift control, and powered parachutes, as well as an independent Rotax Maintenance Technician at the Heavy Maintenance level. He holds a PhD in Air Transportation Engineering from the University of California, and serves as Director of Maintenance for AvSport of Lock Haven.

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TakeTwo
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Joined: Thu Aug 03, 2017 9:24 pm

Exhaust spring replacement

Postby TakeTwo » Mon Oct 02, 2017 3:13 pm

Hi, everyone. I recently became the owner of a Tecnam P2004 Bravo, and I have a couple of questions. During an orientation flight, the instructor pointed out that an exhaust spring was missing;it was quickly replaced by their shop. Now, 15 or so hours later, I have noticed that another spring is missing. Is this going to be a common occurrence? Is this a "get-it-fixed-now" situation? (I ask because I have read of situations where 2 or more were replaced at a scheduled inspection.) Assuming the proper length is available, are the springs found at Lowe's etal acceptable? Can I, as the a/c owner, legally replace them. What else should I know? Thanks.

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drdehave
Posts: 356
Joined: Fri Apr 13, 2012 10:45 am
Location: Davis, CA

Re: Exhaust spring replacement

Postby drdehave » Mon Oct 02, 2017 5:41 pm

They are prone to self-consume, due to vibration. Properly coating them with red, high-temp silicone helps to dampen them and prevent self-destruction. Google it and learn how to apply the silicone. Replace them right away; failure to do so can lead to other vibration-related issues. Get springs from a Rotax supplier, such as LEAF or CPS, not your local hardware store. Can YOU put them on/off? That should be in your aircraft maintenance manual, as it is an LSA manufacturer's decision. I would also encourage getting a spring installation tool and extra springs to carry with you. Just my 2 cents.--Rich
Sting Flight (Flying the Sting LSA)
http://www.youtube.com/user/9162069934/featured

TakeTwo
Posts: 2
Joined: Thu Aug 03, 2017 9:24 pm

Re: Exhaust spring replacement

Postby TakeTwo » Wed Oct 04, 2017 8:47 am

Thanks for the information.

roger lee
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Location: Tucson, Az. Ryan Airfield (KRYN)

Re: Exhaust spring replacement

Postby roger lee » Thu Oct 05, 2017 8:39 am

Your springs are coming off because they need to be stretched a tad more. You shou should have about a fingernails space between each coil. If not take a hammer or pry bar and bend the loops on the exhaust a little wider open. Then safety wire should be run down through the center of the spring. This keeps all springs or parts if they break or fall off off the runway and taxiways. Then apply high temp silicone. DO NOT fill the spring with silicone. This allows the spring to get too hot and not be able to dissipate heat and usually causes premature breaks. Apply the silicone about 3/8" - 1/2" wide and about 1/8" - 1/4" tall. Work it into the spring coils. This will help dampen vibration and keep it in one place.


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Roger Lee
Tucson, Az.
LSRM-A, Rotax Instructor & Rotax IRC
(520) 574-1080 (Home) Try Home First.
(520) 349-7056 (Cell)

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drdehave
Posts: 356
Joined: Fri Apr 13, 2012 10:45 am
Location: Davis, CA

Re: Exhaust spring replacement

Postby drdehave » Thu Oct 05, 2017 9:25 am

And Harbor Freight Tools carries that Red Hi-Temp Silicone--and it's dirt cheap (which, I guess, could reflect on its quality--but it's been working just fine for me :lol: ).
Sting Flight (Flying the Sting LSA)
http://www.youtube.com/user/9162069934/featured

roger lee
Posts: 686
Joined: Tue Dec 08, 2009 11:47 am
Location: Tucson, Az. Ryan Airfield (KRYN)

Re: Exhaust spring replacement

Postby roger lee » Thu Oct 05, 2017 9:45 am

You can buy the high temp silicone in black or red and at any auto parts store or Ace hardware.
Roger Lee
Tucson, Az.
LSRM-A, Rotax Instructor & Rotax IRC
(520) 574-1080 (Home) Try Home First.
(520) 349-7056 (Cell)


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