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How to shim a bearing clearance

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How to shim a bearing clearance
Bearing clearance and setting method using solder and a dial caliper
Thumping If you have a washer extractor that is thumping when in extract this may be an answer.  We know that some machines in 2018 and 2019 were shipped with too large a clearance in the rear bearing.  This article describes one possible solution to a thumping problem.  The other solution is to replace the bearing housing, but this solution requires less effort and yields good results.  

All bearings require some clearance to properly operate.  
In the case of tapered roller bearings we normally measure the axial clearance of the shaft after setting the bearings.  Adjustments are made to get the right clearance.  

On Milnor 30" and 36" washer extractors, with tapered roller bearings,  the bearing clearance is set using shims between the rear bearing cap and the housing.  The shim stack opens the clearance of the bearing for a final setpoint of 2 to 3/1000's of an inch.  

In the ideal world, this setting would happen on a fixture that allows for pushing and pulling the shaft while rotating the shaft under load and indicating the clearance with a dial indicator.  We normally use a Last Word dial indicator in our factory.

In the field, the task gets more complicated.  SInce you cannot easily remove the housing and do not have a fixture, you can use a solder method to indicate the zero clearance fit and then make a shim stack to add .002" of clearance. 

The shims are installed at the red arrow.  This is a sample housing, yours may be different.  

Parts required for the 30022VR machines:
Seal 24S048AAA  -order 1
Shims:
02 03323F - .003" -order 6
02 03323G - .005" - order 6
02 03323K - .020" - order 3
Iif you use any old shims make sure to clean the loctite from the holes.  Do not use a bent shim.  

Parts Required for the 30022V8 machines:
Seal - 24S15840 - order 1
Shims:
02 03324 - .003  order 6 
02 03324A - .005 order 6 
02 03324D - .020 order 3


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1.  To start the process, remove the main pulley and bushing.  
2.  Drain the oil from the housing.  
      You will need 20 ounces of oil to refill.  
3.  Cut a 2x4 the length of the door opening.  You may also want a couple wood shims to lock this in place.  Place the 2x4 cut into the opening of the shell to support the basket.  You are removing the rear support of the shaft, so the basket will drop.  
4.  Remove the rear bearing cap, being careful to not damage the rear oil seal on the shaft keyway.  
5.  Remove the shim stack.  Measure the existing stack with a dial caliper.  Be sure to measure the shims where they are flat, not at the outer edge, where they may be slightly deformed.  Record this measurement.   
6.  Put the cap back on without any shims.  
7.  In the gap where the shims were, put in 3 pieces of solder at 12, 4 and 8 o'clock.  
8.  Press the cap on to pinch the solder.  
9.  Put in the bolts, hand tight.  
10.  Remove the 2x4 in the door front.  
11.  Tighten the bolts using a hand wrench in an alternating pattern, inching the bolts evenly to a "2 finger tight" position using the wrench.  You are attempting to evenly load the bearing cap onto the bearing and pinch the solder evenly in 3 locations.  If you tighten a bolt too much it will skew the carrier.   
12.  Rotate the basket and check the bolt torque to "2 finger tight".

13.  Replace the 2x4 into the door. 
14.  Remove the solder and measure the solder in the pinched area.  Take all three dimensions and add them.  Then divide by 3.  
The result should be a dimension that indicates "zero clearance".  
15.  Now add .002" to that dimension.  Compare this shim stack calculation to the original.  Create a shim stack to the added dimensions of the average solder thickness  plus .002.  (if working on a thumping bearing the new shim stack should be smaller than the original stack)

16.  Place the shim stack on the cap and align with a few bolts.  
Reinstall the cap with the new shims installed.  

17.  Torque the cap in place with a torque wrench. 
18.  Remove the 2x4 and turn the basket.    
Check the play in the basket by picking up on the cylinder.  You should feel little to no play.  It should be less than the play originally felt before you started.   

19. Reinstall the main pulley and bushing and reset the belts.  
20. Refill the oil in the housing.  
21.  Run the machine in extract and listen for thumping.  If none, then you are finished. If it thumps, try the process again.  
 





 
 
 
 

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