Constant speed prop oil leak

There was an AD several dozen years ago that affected [almost] all McCauley
props. The idea was to fill the hub with red hydraulic fluid so that any leaks
would be immediately apparent to the most casual observer.

Yours is leaking. Seal? Probably. Simple? Nothing on a CS prop is simple.
And, according to part 43, an A&P can't get into the guts of a CS prop by
specific reference.

Sending it to a prop shop is going to be painful, but probably not as painful as
you might expect. Crating and shipping is the royal pain in the ass, and if you
don't mind a crosscountry in the ground vehicle to the prop shop, you are not
looking at a tremendous amount of $$$.

On the other hand, they have to pull it apart anyway, so why not just do the
overhaul for the price of a couple of hours of labor and some dollar parts?

Just my 8% of two bits...

Jim



-
-Any ideas how serious this is? Am I looking at a complete prop
-overhaul? Could it be as simple as a seal that the A &P can replace?
-Something in between ???


Jim Weir (A&P/IA, CFI, & other good alphabet soup)
VP Eng RST Pres. Cyberchapter EAA Tech. Counselor
http://www.rst-engr.com

In article ,
Jim Weir wrote:
There was an AD several dozen years ago that affected [almost] all McCauley
props. The idea was to fill the hub with red hydraulic fluid so that any leaks
would be immediately apparent to the most casual observer.

How long does such a prop last if it starts leaking in flight? I've
seen people put up with grease-spitting props for a long time. Even fly
it to the overhaul location. Doesn't seem like you can do that with
oil.

--
Ben Jackson

http://www.ben.com/

On Sun, 18 Apr 2004 18:17:24 -0700, Jim Weir wrote:

snipped for length, not for content.

On the other hand, they have to pull it apart anyway, so why not just do the
overhaul for the price of a couple of hours of labor and some dollar parts?

Was lucky to have a prop shop next door for a few years, will only add
a few thoughts.

On the older McCauley's, at overhaul, the blades have to be unscrewed
from the ferrules (sp?) and inspected. The longer it has been since
this has been done, the more difficult it is, and the more likely you
are to find problems. The newer McCauley hub designs are stone-simple
and relatively easy to o-haul. The only real down side would be blade
rework/inspection (material removed working toward min specs). I would
agree that on a McCauley in most cases overhaul would be the way to
go.

If you've got a common compact hub Hartzell (not applicable in this
particular case), "overhaul" means they have to roll the blade shanks
near the butt and then polish to remove the roll "marks". There is
also a min. diameter for the blade shanks. As above, there are also
requirements for blade rework (accompanied by another set of min
specs). For 91 operators, I've always recommended a 5 year (max)
tear-down, hub corrosion inspection, and re-seal.

FWIW, there were always a lot fewer scrapped parts coming out of the
McCauley end of the shop than the Hartzell end. Corrosion from
infrequent inspection/improper lubrication being the primary issue.

Never saw a corrosion problem inside the Hartzell props on "working"
airplanes (greased every 100 hrs/2-3 months, o-hauled every 3-4
years). Always thought that a grease job every 100 hrs/6 months
(regardless of hours in the air) would be a good idea for relatively
in-frequent flyers.

TC

snip

In article ,
wrote:
Never saw a corrosion problem inside the Hartzell props on "working"
airplanes (greased every 100 hrs/2-3 months, o-hauled every 3-4
years). Always thought that a grease job every 100 hrs/6 months
(regardless of hours in the air) would be a good idea for relatively
in-frequent flyers.

Should grease be added until it flows cleanly from the removed zerk side,
or just until "some" grease comes out?

--
Ben Jackson

http://www.ben.com/

On Mon, 19 Apr 2004 03:15:08 GMT, (Ben Jackson) wrote:

In article ,
wrote:
Never saw a corrosion problem inside the Hartzell props on "working"
airplanes (greased every 100 hrs/2-3 months, o-hauled every 3-4
years). Always thought that a grease job every 100 hrs/6 months
(regardless of hours in the air) would be a good idea for relatively
in-frequent flyers.

Should grease be added until it flows cleanly from the removed zerk side,
or just until "some" grease comes out?

Depends on the installation.

What follows is personal preference for servicing Hartzell compact-hub
props, in no way supported by applicable maintenance documentation.
Worth just what you paid for it. Follow at your own risk.

Hartzell useta tell you to add a "little", sorry don't remember the
exact amount. With the guns we used, it worked out to about 4
"pumps".

Main thing to remember is to add the grease s-l-o-w-l-y, never use a
pneumatic-assisted gun.

If a similiar amount of decent looking grease comes out the
opposite/removed zerk, stop.

If after a shot or two, decent looking grease starts coming out, stop.

If after 4 shots, nothing comes out, 4 more, decent looking grease,
stop.

If the grease looks kinda crappy, carefully & slowly add until it
cleans up. Prop probably needs attention (see t-prop below for
exceptions).

In some cases, grease will not come out. This means that you are
filling the "dry" hub with grease. Prop definitely needs attention.

On turbo-prop applications, 8 times out of 10, the grease will be
compromised. Often will expel water with the grease, or show signs of
water contamination. If the prop is serviced on a regular basis,
carefully "flushing" the cavity with clean grease, it will likely
survive the next o-haul without major corrosion issues.

Only other thing notable is that any Hartzell compact hub prop
installed new (or after o-haul) should be run up to TO rpm, exercised
several times, and the hub cavities "topped off" with grease. Not sure
if that's in the "book" or not. In this case, opposite zerk is
removed, and grease added until excess is seen. Can take a little or a
lot.

Finally, if getting a Dy-Bal performed on a H/CH prop, make sure to
grease it first, just in case someone forgot to "top it off".

Hope this helps;

TC