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cowl flap bushings


Sandman993

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1 hour ago, Sandman993 said:

Hard to make myself pony up $500 for 4 little bolt thru bushings.

A short length of 4130 tubing from Spruce, a hack saw and a file should work just as well.

Clarence

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Thanks men, I appreciate you taking a minute to help out.

My problem is, ...the cowl flaps are in good condition and have always worked fine until recently. On the ground, they work as advertised, but in flight, there's just enough side load that they get a little bound up and only close to half. While that's fine and they stay in that position 70% of the time anyway, at cold higher altitudes, it's hard on the oil temps ( a little too cool), not to mention the 1 to 2kts added drag component. I tried to tweak them last two times the cowl was removed and while they seemed free enough...flying the ship turned out to be a different duck. Think one bushing is gone altogether for whatever reason...lost perhaps, who knows.

Does the spring on the linkage have any effect I wonder? I've looked at it, but can't seem to figure out why it's there or what it actually does.

Thanks again for your time

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Older than me 9" southbend lathe.   Some alum stock. carbide bits from amazon, drill bits.    Fitting with a file.   Check to make sure your linkage is set up properly.   My disconnect was installed backwards.  The disconnect pin is supposed to point to the centerline of the plane.    Mine was reversed so the tailpipe was not fitting well.  

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  • 4 months later...
On 9/30/2019 at 10:32 AM, Sandman993 said:

Anyone know where to get or what a fella can use for cowl flap bushings. Sorry if this has been covered on another thread, but a search didn't find anything.

Hi,

I have the cowl flap bushings if you still need them.

PN is 914039-009.

Thanks, 

Jay,

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Hopefully, I found the issue...

after replacing bushings, the cowl flaps continued to be problematic. After searching for the real problem ( hang from the ankles under the engine deep under and back at the firewall) found the cable had let go at the area where the tube sleeve connects near the linkage. Called lasar and the wanted $775 for cowl flap cable. Geez! So I slipped a 3/8” dia section of hose over the segment and added clamps. Works great and it simply replaced another piece of plastic that married the part of the cable to the steel tube that carried the cable and keeps it stiff. Plenty of patience because it’s like buildIng a ship in a bottle. Am happy to report, no blood was donated in the effort.... as I usually bleed a little when working upside down in the area of firewall and engine.

so far, so good.

 

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  • 4 months later...

One of the bolts on a hinge point on my right cowl flap departed the airplane, so I purchased the replacement bushing (McMaster Carr) and bolt (can’t remember where I got it.) Worked fine. 
Less than a year later, same thing: bolt and bushing lost somewhere over WI! What am I doing wrong? If I tighten it too much, it binds. Is there a special bolt that goes into the cowl flap nutplate? Lockwasher?

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1 hour ago, PeytonM said:

One of the bolts on a hinge point on my right cowl flap departed the airplane, so I purchased the replacement bushing (McMaster Carr) and bolt (can’t remember where I got it.) Worked fine. 
Less than a year later, same thing: bolt and bushing lost somewhere over WI! What am I doing wrong? If I tighten it too much, it binds. Is there a special bolt that goes into the cowl flap nutplate? Lockwasher?

Do you still have the captive fastener that's riveted to the cowl flap?   If so, that may need to be changed if it isn't holding the bolts in place.   There should be a thin, smooth washer between the bolt head and hinge that allows the bolt to move in the joint with minimal friction to the bolt head.   Also, make sure that the bushing is really isolating the hinge from the bolt, i.e., there's not sufficient gap that the hinge gets between the bushing and bolt and grabs the bolt.

Mine nearly sawed through the bushing and the bolt before I decided there was too much play and changed it.  ;)

 

20200322_193729.jpg

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