Wonderful. I did the EXACT same thing in May. Rebuilt all three gear cylinders due to 1 slight leak. Result. Massive hydraulic leak problems that persist to this day. I’ve now replaced two entire cylinders and may need to replace the third…
I’m at a loss, frustrated, and in desperate need of a shop in the southeast that will help me TROUBLEshoot the problem (as opposed to continually replacing cylinders).
Matt
From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of kneaded pleasures
Sent: Monday, October 29, 2007 1:59 PM
To: lml@lancaironline.net
Subject: [LML] Gear cylinder hydraulic gaskets
Matt Reeves wrote back in late August:
"I have a Lancair 320. I just found a leak coming out of the end of the left main hydraulic cyl on the high side. It is not coming out of the fittings, it's actually coming out of the end where the stop jam is. It's just a small leak but I rebuilt this cylinder once already cause I thought there was an internal leak so my opinion is this is a defective cylinder."
Matt: The problem is probably not with the cylinder - or your workmanship! It is probably due to a wrong piston gasket being included in the cylinder rebuild kit. I had an identical problem with one cylinder and chose to rebuild all three gear cylinders at the same time. After ordering rebuild kits (just gaskets in the kits) I installed the new gaskets and two leaked after rebuild. I removed them and critically reexamined the supplied materials and my workmanship. (Meanwhile, I reordered from Lancair two more gasket kits.) I then noted that the newly-supplied leaking gaskets differed from both the very old rotted gaskets that I had originally removed and also differed from the two newest gaskets that I had just received from Kit Components. (The gasket that I am targeting here is the gasket that surrounds the piston as it extends/withdraws from the cylinder.)
The differences in these gaskets are easy too see and measure. The new and correct gaskets are the same as the very-old, original and now rotted gaskets. They have an O-ring embedded inside of the plasticized gasket. {I "dis-sected" (the word is not "di-sected") an old gasket to observe this.} Writing on the good/proper/desired gasket is illegible to me. However, writing is very clear on the IMPROPER gasket and it reads, "USA .375 MP I K3E.1". Further, the good/non-leaking gasket stands noticeably higher on a flat surface - perhaps four or five mils higher than the poor/leaking gasket (probably important at 2000 psi).
Summarizing, don't throw away your leaking cylinders before you first check to ensure that the correct replacement gasket is installed. Look for the tell-tail embedded "O ring" that is prominently visible on the top of the correct gasket. Greg Nelson