Hi Linda,
In response to your question(s), I forward my earlier post (below).
The next to last paragraph and the one before it pertain directly to
the subject raised.
Your coupe is a late one...not the serial range between 113 and 812
that Fig. 11 applies to.
I would tend to believe that your oleo seal, whether the original
AN6227-17 O-ring (see Fig. 12, item 15) or the rubber cup (see Fig. 11,
item 8a), is failing. In the process of landing some of your oleo
fluid is finding a new "path of least resistance"...out the filler
instead of up into the piston (new "path of least resistance"). As
fluid is lost you will have progressively less effective oleo action on
that main gear leg. Maybe none very soon.
I would recommend having your mechanic remove that oleo cylinder (see
Fig. 12, item 23) and verify if you have the original AN6227-17 O-ring
or the rubber cup. Also verify if the oleo fluid used when topping up
last annual was of the correct type for the seal installed. Get the
parts needed ordered ASAP.
Have the seal replaced...in either case I would recommend the rubber
cup. Individual cups are available as Skyport part number SS12301. If
that conversion has not yet been done, purchase and have installed
Skyport "cup kit" SMK-61. Afterward you will use brake fluid in your
oleos...hydraulic (red) oil will destroy the rubber cup(s).
No later than next annual, have the inside of the oleo cylinder(s)
examined for smoothness. I would have them honed and both pistons and
cylinders well flushed before reassembly. If your rubber bumpers
(item 12-24) are old and hard, broken or distorted, this would be a
good time to replace them too.
Regards,
WRB
--
On Jun 2, 2010, at 00:46, Linda Abrams wrote:
On p. 12 of the Skyport parts catalog, there are two different parts
of the drawing that both have the number "14" by them. The one that
is farther up the page has an arrow from the 14 to what looks like a
tiny screw-in plug or fitting...but in the parts' names' list on the
right-hand page, only the *other* "14" is listed ("Wheel & Drum
Assembly"), not this number 14. Can anyone please tell me the name
of the item 14 that is farther up the page?
There's a little leak coming from that item, on my right MLG. What
needs to be done about that, and how quickly does it need to be
done? Thanks!
Linda
N3437H (Sky Sprite)
L.A.
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Begin forwarded message:
From: William R. Bayne <[email protected]>
Date: May 28, 2010 13:46:46 CDT
To: [email protected]
Subject: Re: [ercoupe-tech] Re: Filling the MLG struts
There is more than a little possibility of confusion by the less
experienced in reading these two posts.
I agree with Alan that the rubber cup is a better design (for proper
long term oleo seal service) than the O-ring installed in later birds.
The rubber cup was the earlier design, though. IMHO, the O-ring was
NOT an improvement; but if your oleos are not worn to the point that
the O-ring cannot seal properly, or needs replacement often, install
the Skyport "cup kit" SMK-61. It is the "better now" to which Alan
refers. Individual cups are available as Skyport part number SS12301.
For anyone interested, the oleo snap ring (part number 415-33229-1,
see Fig. 12, item 18, NOT clearly shown and perhaps no longer
available from Univair or Skyport is/was a "Reliance Light External
Ring for 1.250 shaft, .125 x .620 wire section, .250 gap, style #6
gap" from Eaton Mfg. Co., Massilon, OH.
Donald is correct that DOT 3 brake fluid will destroy oleo O-rings
(just as hydraulic oil will destrot rubber cups). That should come as
no surprise, as this the lubrication instructions are specific. Many
mechanics don't know about the Skyport kit, and blindly service oleos
according to ERCO's serial number recommendations (thus assuring
failure of installed rubber cups on later birds). If rubber cups are
installed, brake fluid MUST be used as oleo fluid. It may be that DOT
5 (silicone) brake fluid will not destroy AN O-rings...I have not
tested that.
The "old time spring cap" (and tube) deteoriate. Due to rusting, many
no longer have spring closure action. Replacements are available from
Skyport (and perhaps Univair). Forney used Gits Bros. #402, Style
"E", but there may be other sources of such a generic item. Some
mechanics, not knowing that replacements are available may have tapped
the oleo hole to receive the pipe plug Alan describes.
The pipe plug was "production" on Ercoupes through serial 812 (per
Parts Catalog Fig. 11, p. 12, (upper) item 14. If this item were
correctly referred on facing page 13, I believe it is the final item
listed under 12a as "AN913-1D, Plug - hex (415-33166-3).
Due to the many production changes to Ercoupe design and service
parts, it is important that posters identify the serial number of the
aircraft their experience (and information) relates to. A list of
many of such changes in inside the back of the Service Manual. "One
size DOES NOT "fit all" in this context, and no one intends to mislead
or wants to be mislead.
Regards,
William R. Bayne
.____|-(o)-|____.
(Copyright 2010)
--
On May 27, 2010, at 12:17, Donald wrote:
You speak of a filler plug with safety wire. My two sets of struts
have an old time spring cap like was used on oil holes a long time
ago, must be a change along somewhere.
I opted to use only new O rings, and the red aviation hydraulic
fluid, nice and oily. After seeing what brake fluid did to my other
set, no brake fluid for me.
.--- In [email protected], ALAN FAIRCLOUGH
<texasavia...@...> wrote:
How to and what not to do...
I have found there are several things to watch out for.
First of all, jack up the plane so the weel extends all the way down.
Push the wheel up and down to feel the current hydraulic damping.
If it is good, your sysyem is working and may just need topping off.
If it is not you will feel it when pushing the wheel up.
First thing to check is the bumpers. these are little rubber stops
on the landing gear leg and on the strut. When the wheel drops down,
the motion is stopped by a rubber bumper that is attached to this
little arm. If it is missing, which is quite common, you are in
trouble.
The wheel has been dropping too far down, the filler hole has a
rough edge on the inside of the
cylinder and it destroys the seal. if you have a seal cup version.
If you have the O'ring version, you need to take it off and get a
seal cup kit from Skyport.
The O'ring version was made to last 10 years at best and none will
last long. It was a great idea at the time but there is better now.
When you take the cylinder apart, you will see if you have the cup
or the O'ring. You can leave the O'ring on as it will not harm
anything. You will have to wash out the cylinder which is made of
steel and probably has rust on the inside. Go to the auto parts
store and buy a small 3 blade fine ctlinder hone that will fit
inside. ( take the cylinder with you to test if it fits or make a
second trip). You then hone out the inside surface with this device
in a power drill and with diesel or kerosene in the cylinder. If you
don't do this, the rust will eat up your cup seal.
Wash it out well. Clean up the piston surface with sandpaper and
diesel or with a wire wheel brush and install the cup kit as
instructed.
I find it is easier to fill the cylinder before installing it on the
plane. Just pour the fluid into the cylinder and inser the piston
seal and slowly push it down. Any excess fluid will come out the
fill hole. inser the plug into the fill hole and safety wire.
Put it on the plane and test the damping motion.
If you need to top off the fluid, remove the rubber bumper and
inspect it. Drop the wheel as low as it will go and add fluid
through the filler hole. I use that syringe the dentist gave me to
irrigate my wisdom tooth hole. An old oil can also works.
The U cup seal is now above the filler hole. Do not push the wheel
up now.
Fill with fluid until it runs over and then push a wooden chopstick
into the hole to carefully help the cup lip over the filler hole
inside surface while slowly pushing the wheel up. Once the U cup
seal is below the filler hole, prop the wheel up so it does not drop
again and re-install the filler plug with safety wire and re-install
rubber bumper.
With the rubber bumper installed, you can now drop the wheel all the
way down again and the U cup seal will remain below the filler hole.
Now test the damping.
