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To:  lml@lancaironline.net
Date: Fri, 03 Jan 2014 08:42:49 -0500
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From: George Wehrung <gw5@me.com>
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Subject: Fwd: Landing gear shimmy
References: <BB18EA2F-97A5-43E3-B531-AA590CE5BFAE@me.com>


> Ron,
>=20
> We, I mean Sam discovered the drag link was loose.  After checking the bol=
t, the strut ears, and the drag link bolt cylinder we reinstalled and torque=
d it.  No more movement of the strut.  However, we discovered it only has 5"=
 of the chrome showing, so we know it's low in PSI.
>=20
> Sam also brought me a shim kit and mentioned that some had kept it in plac=
e by using zip ties.  Is there any other ways of installing it and retaining=
 it in place?
>=20
> George
>=20
>=20
>=20
> Sent from my iPad
>=20
>> On Jan 2, 2014, at 7:41, Ron Galbraith <n5es@mac.com> wrote:
>>=20
>> Hi George,
>>  There are several things that might cause the shimmy in the main gear.  T=
he first thing is warped rotors.  You can either replace the rotors or get y=
ours machined for a pretty small cost.  Grease or oil on the brake pads/roto=
rs can also cause the brakes to grab in an uneven way.  the wheels/tires bei=
ng out of balance can also cause it.  The biggest cause is usually play in t=
he main gear leg.  The only way to know for sure about that is to jack up th=
e airplane to get the weight off the main gear and just grab it and move it.=
  If the gear leg moves at all, then you need to shim the gear leg.  You can=
 get shim material from Lancair.  Some have heated up the receptical and use=
d dry ice on the gear leg so when you put the shim on, it=E2=80=99s easier t=
o get in, then when the gear goes back to normal temp it=E2=80=99s very tigh=
t.  I=E2=80=99ve heard of others using lock tite but I=E2=80=99m not positiv=
e about which version to use. =20
>> This is for the main gear but it sounds like you may have a nose strut is=
sue too in that the nose strut isn=E2=80=99t dampening enough.  You need to d=
o a =E2=80=9Cgrease plate test=E2=80=9D to verify.  Also, I=E2=80=99m not po=
sitive which nose strut you have.  Is it the older version or the new one?  =
 If it=E2=80=99s the old one then I would say for sure you really need to ge=
t it overhauled.  Once you get a bad nose shimmy, the O rings in the older s=
trut are certainly damaged.  The new strut is different and might just need s=
erviced.  The old strut has the shredder valve on the front middle of the st=
rut and the new one has the valve on the back lower part of the strut.  If y=
ou have the new one, make sure there=E2=80=99s at least 6-7=E2=80=9D of silv=
er showing.  On the older strut you should have about 2-3=E2=80=9D of silver=
 showing. =20
>> Let me know if there=E2=80=99s any other info I can help you with.  Where=
 are you keeping the airplane?
>>=20
>> Ron
>>=20
>>=20
>>> On Jan 1, 2014, at 11:06 PM, George Wehrung <gw5@me.com> wrote:
>>>=20
>>> Ron,
>>>=20
>>> We bought N84FA from the Rooneys. I know Tom had called you for advice. =
 Well it's my turn if you don't mind. =20
>>>=20
>>> I have seen lots of posts on the shimmy.  Ours also is predominately wit=
h the right main gear and appears when I have to use heavy braking and like l=
ast night did enough damage to vibrate the screws loose in the nose gear fai=
ring.  The shimmy did not end until we had slowed below ten knots.
>>>=20
>>> I have seen references to using shims in the hole the gear leg bolts to i=
n the fuselage.  But I don't how well this works, how hard it is to put in a=
nd if the kit is something Lancair sells.
>>>=20
>>> Thanks for the help in the long list of things we need to fix.
>>>=20
>>> George
>>>=20
>>>=20
>>>=20
>>> Sent from my iPad
>>=20