Luke,
What type hose did you use in your system? The black deposits could not have come from the stock hose - different color internally. All the seals are black. Some fine blackish residue will come from the pump gears. Were the black pieces you found a rubber like substance?
I too would replace the hose even though the exterior black covering is merely protections for the structural layers beneath.
Chris
Chris Zavatson
N91CZ
360std
From: "lalcorn@natca.net" <lalcorn@natca.net>
To: lml@lancaironline.net
Sent: Mon, October 25, 2010 6:00:10 AM
Subject: [LML] Hydraulic hoses
George, replace your hoses. If the outside has deteriorated, then the inside is as well. My aircraft also had 15 year old hoses that were falling apart. I redid all of the hoses and when I took the pump apart for an overhaul, I found black residue all over the inside of the pump and resevoir. I would suggest you check your pump and cylinders as well. The degrading lines destroyed all of the seals in my gear door cylinders, which I had to rebuild. The main cylinders were already rebuilt a year before, and the seals were still good. The hoses
are cheap to make. i am still cleaning out black pieces from my system. Even though the filter on the pump caught alot of it, the spool valve was still covered. I was amazed the gear still worked.
Luke Alcorn