Rock-afire Mac Valve Maintenance

An official procedure for MAC valve rebuilding is documented in the ShowBiz Pizza Place Operations Manual from 1981.
  1. Remove snap ring or spiral ring from top of spool
  2. Remove plastic cap and spacer
  3. Carefully remove the spring and spool trying not to damage or scratch up the inside metal
  4. Inspect the spool to make sure there is no dirt or debris in the mac valve casing or spool
  5. Remove and replace the 2 O-Rings on either side
  6. Clean the spool and casing of old grease with water and soap
  7. Lubricate the spool and casing with white lithium grease
  8. put the spool in the casing being sure the hallow end is facing up
  9. place spring into the hole at the top making sure it goes in strait and there's no obstructions
  10. place small white spacer onto spring making sure it is strait
  11. place white cap on top of white spacer being sure the groove lines up with spacer
  12. push down on cap and put the snap or spiral ring on making sure it went to the locking groove
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