026 crankcase seals

[shorty4655]

Hey Guys,

First post here I'm from Qld Australia and I'm rebuilding an old 026c. Just putting in a new piston as the original was harvested by the person I bought it off to rebuild another saw. Anyway I picked up the saw minus the piston (and bar and chain) for $100.

I have a meteor piston kit with caber rings to go in and I have read here the crankcase seals are known for leaking so I am planning to replace those (visually look fine but I am ordering a vac brake test kit to check).

My main question is regarding the seal depth for seating. On my 026c the flywheel side is sunk below the edge of the case by 3-4mm, is this the oem position? I ask as I don't know if these seals are the OEM from factory or if they have been replaced and driven too far? The clutch side is essentially flush with the case. I had a look at the 026 service manual and it doesn't really elude to any set depth all it says is press it home fully with press tool. Often I see YouTube videos of people replacing that flywheel side seal to be flush with the case hence my confusion. On the flywheel side can you drive the seal too far? Is there is a lip which prevents it going further so you know the right depth for it to sit at.

Any insight would be great.

 

[kd.rodgers]

Ah the 026c! Those are great saws.

Regarding the seal depths - yes, having the flywheel side seal sunk in 3-4mm below the case edge is normal and correct for that saw. There should be an internal stop/lip inside the crankcase that prevents driving it in too far. So no need to worry about over-pressing unless you really lean on it with the installer.

The key is having it seated fully against that internal stop to prevent leaks. Flush or slightly recessed is fine. Sometimes if folks drive seals flush or protruding from the case, it actually lifts the seal off that inner stop which can then cause leaks.

 

[shorty4655]

Ah the 026c! Those are great saws.

Regarding the seal depths - yes, having the flywheel side seal sunk in 3-4mm below the case edge is normal and correct for that saw. There should be an internal stop/lip inside the crankcase that prevents driving it in too far. So no need to worry about over-pressing unless you really lean on it with the installer.

The key is having it seated fully against that internal stop to prevent leaks. Flush or slightly recessed is fine. Sometimes if folks drive seals flush or protruding from the case, it actually lifts the seal off that inner stop which can then cause leaks.

Excellent news! Basically what I thought, I'll setup a vac test before replacing the seals just to be sure these ones are bad, if they don't leak I see no need to replace em and I'll just hang onto my newly ordered seals till I need to do it. Also be worth while doing to vac test to ensure the crankcase manifold seal is still good as it's rather avoid splitting the case if I can, the bearings feel tight with no play so no need to open it if I can avoid it.