Stihl 044 pressure leak past bearing spacer

[NewToStihl]

I've recently had two Stihl 044 saws fail a p/v test for the same reason; leakage between the bearing spacer and the crankshaft (PTO side). I've had a handful of these saws in the past that held tight with no issues. Since the bearing spacer isn't a press fit onto the crankshaft it seems perfectly reasonable that it could/would be a leak point, but I'm wondering why all of a sudden these two are leaking when others held. Is that just indicative of wear from use? If so, is the wear typically on the crankshaft or the spacer, or both?

Thanks!

 

[Adirondackstihl]

Early saws had an o-ring behind the spacer. You could try that.
Is there a grease film on the crank or is it dry?

 

[jockeydeuce]

If you don't have the clutch tight against the spacer during P/V test it will leak.....The early one do have the tiny o-ring though like Airondackstihl mentioned, but Stihl discontinued using it.

 

[NewToStihl]

Early saws had an o-ring behind the spacer. You could try that.
Is there a grease film on the crank or is it dry?

Interesting - none of the saws I've happened across had the o-ring? I'll have to look into that.

Don't know about a grease film - I didn't pull the spacer off yet. That is one thing that crossed my mind, that perhaps a coating of grease was intended to keep the seal?

 

[NewToStihl]

If you don't have the clutch tight against the spacer during P/V test it will leak.....The early one do have the tiny o-ring though like Airondackstihl mentioned, but Stihl discontinued using it.

I tested it first fully assembled, then I pulled the flywheel to check that seal, but it was solid. I could hear the leak from the PTO side before stripping it down to a bare crank and checking with oil for bubbles.

That's an interesting thought about the clutch needing to be on tight in order to prevent the leak - on that point, if there was any minor wear or damage to the mating surfaces of the large end of the spacer and the bearing it seats against it would allow leakage. I'll have to look into that.

 

[jacob j.]

Like Rob said- they're designed to have the clutch providing pressure against the spacer. The O-ring was not a reliable part- it would harden and fall to pieces, hence Stihl's decision to discontinue the part. Those spacers do wear and eventually need to be replaced.

 

[DELETED (Struggle)]

I put a thin coat of motoseal on the shaft on mine when I assembled it and have had no problems. On vac or pressure test.


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