Stihl Mystery bearing??

[juanni]

Well in my search to get new crank bearings for a 031AV I have fallen down into Stihl's numbering system.

I found a pair of 9523 003 4440 bearings, only when I received them one is a 9523 003 4340.
I called the dealer to trace back that 9523 003 4340 to find out what it fits. Because it is a NLA part they don't have it in the system at all.

I looked at various IPLs for other Stihls in that size range and don't find it either.
Anyone have any idea what saw it fits?
Maybe it isn't even for a saw?

Guy on Ebay has one listed for a flywheel side 030 bearing, but not according to a 030 IPL.

Googling just goes in a big circle back to ebay.

 

[atpchas]

Best I can offer is a reference to part 9523 003 4240 replaced by part 9523 003 4340 with a reference to tech note TI 8.73 which I don't have. Perhaps someone who has that tech note can research what's going on.

 

[juanni]

Hmmmm...... can't find anything googling 9523 003 4240 either.
The 9523 003 4340 has a flange so I assume it was for a motor with the cases split right through the bearing.
Like this one. http://www.ebay.com/itm/Stihl-Crank...629729?hash=item2ecdd2a521:g:LLEAAMXQVT9S2VQg

 

[juanni]

Well I emailed Stihl Tech Dept and they responded that they don't have any records on NLA parts.
Don't think I have ever had this kind of experience with any manufacturer before??

 

[Steffen]

Shure its not INA??
That is an old german bearing factory. Stihl used them back in the 60s and 70s. It is now part of FAG wich is under the Schaeffler Group.

 

[backhoelover]

see if this helps, might, might not

 

[DND 9000]

Best I can offer is a reference to part 9523 003 4240 replaced by part 9523 003 4340 with a reference to tech note TI 8.73 which I don't have. Perhaps someone who has that tech note can research what's going on.

That TI 08.1973 was about: Ball bearing for Crankshaft; Clutch cover plate; Clutch spring; Fuel filler cap; Spark plug; Choke shutter; Hand guard

I don`t have this TI, I only know that this was explained in that TI. That TI was for 031 and 031 AV

 

[backhoelover]

dang im good

 

[backhoelover]

 

[VinceGU05]

i machined up the PTO side bearing rather than stihl's $120 bearing

 

[smokey7]

45$ was too much 120 is just nuts. Match it up a d run it.

 

[juanni]

"Shure its not INA??
That is an old german bearing factory. Stihl used them back in the 60s and 70s. It is now part of FAG wich is under the Schaeffler Group."


The bearing is a FAG but it is NLA (No Longer Available from Stihl) and so isn't in their system at all.

 

[juanni]

dang im good

Yes you are but it adds to the mystery.
From that tech bulletin....

The hitherto existing ball bearing with oil seal 9523 003 4240 on the sprocket side ·of the crankshaft will not be supplied as spare part any longer. Also the retaining ring 9459 620 2600 which has been used for fixation of the bearing in the crankcase will not be available as spare part any longer.
For spare needs we will supply from now on the new reinforced ball bearing 9523 003 4340.
This ball bearing is not any longer provided with a groove at the outer race for the snap ring but with a collar. Prior to the installation of a new bearing the crankcase has naturally to be warmed up as well.
Existing stock of the ball bearing 9523 003 4240 should be used on those machines which are not exposed to hard operating conditions.

The 031 IPL I have says bearing 9523 003 4440 and snap ring 9465 620 2620, not even the snap ring has the same part number??
The bearing is installed from inside the case and butts up to the snap ring.

On either of the 2 used versions of the bearing I have, NEITHER have a snap ring groove on the bearing race, the snap ring is in the case.

This updated bearing 9523 003 4340 has a shoulder, but because the case isn't machined internally for a shoulder it would be impossible to get the bearing/crank/case in the proper location. There would be about 1/8" gap between case halves. The bearing can't be installed from the outside with the shoulder butting the case because the seal would be on the wrong side.

^Old Bearing, the bearing located by the snap ring in the case. Notice the small gap between the crank and case.



^9523 003 4340 Much larger gap between crank and case. 0.090" difference.

That tech bulletin doesn't seem to apply to any of the three or four 031s I tore down for parts.

 

[backhoelover]

let me do some looking

 

[backhoelover]

there is not a tech bulletin covering the change in the bears and case. that is weird

 

[juanni]

The whole thing is weird.
That tech bulletin is dated march 1973, and the 031 was introduced in 1971.
Maybe the later saws abandoned the snap ring on the bearing race, shoulder on the bearing race for a snap ring in the case?

All the bearings I took out of the 3-4 donors looked like Vince's above.
No shoulder, no snap ring groove in the outer bearing race.

 

[VinceGU05]

The snap ring is just to hold the bearing /assembly from possible drifting out. My 084 beating looks like the one on the right as well.

 

[juanni]

Yes I know what the purpose of the snap ring is for.
And yes I know that purpose can be done by other methods like a having a shoulder on the bearing, but that isn't the question.

The question is what does 9523 003 4340 fit, and why does that 031 tech bulletin not apply to any of the 031s I have or even the one you modified that bearing for?

 

[noooool]

Thought I should jump in with the info I have at hand here. May be no help at all but here it goes...
Bearing 9523 003 4240 was last available from Stihl factories in 1973.
It was superceded by 9523 003 4340 which was last available from the factory in 1978.
One of the parts lists I have here says it fitted the 030, 031 and 032
One of the other lists seems to agree with the tech bulletin and only lists it for the 031.
Current Mediacat info says to use 9523 003 4440 (but seems to indicate that a different spur gear and thrust washer are needed?).

 

[phantomblack]

Sorry to dig up an old post, but i am in the exact same position as described above. Has anyone figured out what the appropriate PTO side bearing is for an 031?