Replacing Needle Bearings


How they work          diagnosing problems          porting and polishing          rebuilding nosedrives          Swaps and upgrades          Adding a boost gauge         

replacing needle bearings     adding a nosedrive drain          supercharger oil change          pulley size suggestions          links, references, and sources


NOTE--This procedure will not work on the GenV M90 Supercharger.  The needle bearings are not a full-cup design, and cannot be ejected by forcing grease on the back side.  This procedure will work for M62 Gen2 and Gen3, as well as M90 Gen3.

 

The inlet end of each rotor shaft is held within a needle bearing.  When rebuilding (or after you get the mess from porting and polishing) you should replace these bearings.  Particularly if you used any kind of cleaner or solvent on the rotors that may have disrupted the grease, or if the supercharger was left in an environment that may have caused the bearings to rust.

Removal is actually fun.  Start by collecting the following:

 Letter drill "R", 1/8NPT tap, 1/8" brass pipe nipple (threaded both ends), 1/8" NPT coupler, 1/8NPT grease (zerk) fitting:

 

Locate these two holes on the bottom of the Supercharger. Their original purpose was to prevent compression when the original needle bearings were inserted, to prevent air behind them from compressing and ejecting them:

 

CAREFULLY drill out the hole with the Letter R drill. If you don't have an R, go to a 11/32" drill (0.3438), slightly larger. Do NOT hit the bearing. Drill straight.
If you mar or gall the bearing, it will leave a groove in the bearing pocket of the SC as it comes out:

 

Carefully tap 1/8" NPT threads into each hole. Use oil. Get them as deep as you can without hitting the bearing:

 

Results of tapping:

 

After assembling the brass parts and zerk, carefully insert and thread it in without cross-threading. Get it snug. Use a helper and put a good-quality grease gun on the fitting:

 

 

Pump away until the bearing comes out. Sometimes they come out with significant velocity. If your helper is your significant other, and you're horny,
lay a rag inside the SC to 'catch' the bearing. If your helper is anyone else, aim it in their general direction, and you might get a good show. Of the 4 I've
done, only one came with velocity. The term for the aftermath is 'Gicky'. You can see the first bearing starting to come out. This one DID have velocity, and
Linda, my trusty helper, got 'Gicky'. Very Happy If you look closely at this picture, the bearing on the right is starting to come out:

 

The mess you have to clean out (all of it, use solvent) so you don't have a pre-lubed bearing that wants to move around later:

 

Ready to press new bearings. Press them just below flush (to the same depth as the original bearing depth):

 

You should have already ordered these replacement bearings (pre-greased).  You can get them from one of the suppliers linked in my links section (photo courtesy of www.rollingperformance.com):

 

Set up the press.  I used a large socket and extension, with the 17mm socket upside down on the extension, so the flat face of the socket would press on the rim of the bearings:

      

Press the 2 bearings to the same depth as the old bearings (slightly below flush).  The case is now ready for the rotor assembly to be installed, and you're ready for another beer.


How they work          diagnosing problems          porting and polishing          rebuilding nosedrives          Swaps and upgrades          Adding a boost gauge         

replacing needle bearings     adding a nosedrive drain          supercharger oil change          pulley size suggestions          links, references, and sources


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