lml@lancaironline.net Mailing List Archive

John,

Rubber will last much longer if submerged in oil. The failure may simply be due to nothing more than the years of sitting idle.

In terms of the seal installation, I would recommend using Dow Corning 737 (see SI 1324C, 2009), Pliobond is offered up as an alternative if the 737 is not available. After having recently changed a shaft seal, I highly recommend sticking with the 737, in particular for the do-it-yourselfer. It provides much more working time and is easier to handle than contact adhesive. I can see many A&Ps not wanting to use it because of the longer cure time (24 hours).

Chris Zavatson

On Thursday, December 5, 2013 4:38 AM, John Cooper <snopercod@comporium.net> wrote:

When my O-290-D2 was on the engine stand last month, a large puddle of engine oil gradually appeared underneath. The front crankshaft oil seal had to be the source of the leak so I resolved to have it replaced before my first flight. I've been bugging the local A&E to R-and-R the seal, but he's been too busy or something. So today I removed the old seal myself with a hook and ordered a replacement seal and some Pliobond 20 at Aircraft Spruce. Here are a couple photos of what I found in there. Now keep in mind that this engine was built up by Don George of Orlando, FL in 1991, and only has 4 hours on the Hobbs:

Look at all the cracks in the seal! It's no wonder that oil was leaking out! Furthermore, when I started cleaning out (with M.E.K.) the recess where the seal went, I noticed that there were several pieces of silk thread intruding into the seal area at the case part line (another mirror shot). I cut the silk thread off with a sideways razor blade on a stick:

I'm just posting this for information, but all comments are welcome, as always.

I plan to use the EAA method as well as Lycoming Service Instruction 1324 to reinstall the new seal. Wish me luck.