Intro and Tool Question

sledgehammer · Jul 23, 2007

Hi folks,

Been a long-time reader of this site - a lot of good & knowledgeable people here...

So - i'm rebuilding a stihl 038 i was given and i need to replace the clutch-side bearing. The manual says to use an arbor press to remove the bearing. so my question is - what capacity press would i need for this (and i guess general small-motor work) ? would a 1 ton do the job or would i be better getting something a bit bigger? maybe a 2 or 3 ton unit?

Cheers
Sledge

Al Smith · Jul 23, 2007

There is a little more to it than just a arbor press.You don't even need one.

Those bearings are shrunk fit on both the crankshaft plus the bearing pocket of the crankcase halves.

Some may want to disagree but the easiest way to disassemble the thing is to use a heatgun [hair drier]on the bearing pockets to expand the metal just a tad which would allow you to pull the case half off the bearing ,one side at a time.

Once the crankshaft is removed from the case halves,an overnight stay in a cold deep freeze will usually allow the bearings to literally fall off the shaft.Assembly is just the opposite of disassembley.Freeze what you want to shrink and heat what you want to expand.Do not beat on the bearing with a hammer.

greengoblin · Jul 23, 2007

A small deep fat fryer works great to heat bearings when they are ready to go back on

chowdozer · Jul 23, 2007

How come my french fries taste like 2 smoke mix?

Lakeside53 · Jul 23, 2007

Al Smith said:
There is a little more to it than just a arbor press.You don't even need one.

Those bearings are shrunk fit on both the crankshaft plus the bearing pocket of the crankcase halves.

Some may want to disagree but the easiest way to disassemble the thing is to use a heatgun [hair drier]on the bearing pockets to expand the metal just a tad which would allow you to pull the case half off the bearing ,one side at a time.

Once the crankshaft is removed from the case halves,an overnight stay in a cold deep freeze will usually allow the bearings to literally fall off the shaft.Assembly is just the opposite of disassembley.Freeze what you want to shrink and heat what you want to expand.Do not beat on the bearing with a hammer.

Not sure about Al's method on Stihls. Generally (but not always) the Stihl bearing stay in the case, particularly on the Clutch sides where most have a steel insert. And when they do stay on the crank, they won't come of without a puller. Be carefull with a heat gun or hairdryer when your bearings have poly cages.

Check out the thread "splitting 066 case"... It's exactly the same process for the 038.

http://www.arboristsite.com/showthread.php?t=40590