\nMoen has several shower valve styles.
\nTheir trims and cartridges do not always swap.
\nMoen has a helpful guide for shower trim matching.
\nYou can read it in the Moen trim replacement guide<\/a>.<\/p>\n
If you plan to use Posi-Temp trim, check the fit first.
\nA custom plate may cover the wall opening.
\nBut trim fit is not only about looks.
\nThe handle must work the cartridge correctly.
\nThe stop tube, screws, and depth also matter.<\/p>\n
Question<\/h2>\n
Can I rebuild an old Moen or Stanadyne cartridge instead of replacing it?
\nAlso, should I drill out the cast restrictors for more shower flow?<\/p>\n
Answer<\/h2>\n
For best results, collect known-good cartridges now. Be careful with flow changes. Removing showerhead restrictors can also cause problems. If you want more comfort, look at the full system. Saving an older Moen or Stanadyne valve can be a smart project. I’m Chris Mayer, writing for Plumbing 101<\/a>.<\/p>\n
\nReplacing the cartridge is usually the better choice.
\nRebuilding may work for small seal problems.
\nBut old brass, plastic, and rubber parts can be worn.
\nA new cartridge is more reliable when one is available.
\nI would not drill out cast restrictors in the valve.
\nThat can damage the valve body.
\nIt can also affect pressure balance and safe operation.
\nUse proper pipe sizing and a code-approved shower valve instead.
\n<\/strong><\/p>\n
\nKeep the valve model information with each cartridge.
\nTake pictures before removing old parts.
\nLabel the trim, valve body, and cartridge style.
\nThis makes future repairs much easier.<\/p>\n
\nA tub outlet often flows more than a shower outlet.
\nBut piping a shower from the tub port may create issues.
\nIt may also affect how the valve was designed to work.
\nA plumber should check the local code before doing that.<\/p>\n
\nThe EPA says standard showerheads use 2.5 gallons per minute.
\nWaterSense showerheads use no more than 2.0 gallons per minute.
\nYou can learn more from the\u00a0EPA WaterSense showerhead page<\/a>.<\/p>\n
\nCheck supply pipe size, valve type, pressure, and showerhead design.
\nA clean cartridge can also restore lost flow.
\nSo can flushing debris from the valve body.<\/p>\n
\nBut avoid changes that weaken the valve.
\nParts matching and safe flow matter most.
\nThat keeps the shower useful, safe, and easier to repair.<\/p>\n![\"Old](\"https:\/\/plumbing101.i234.me\/wordpress\/wp-content\/uploads\/2026\/05\/Old-Moen-Shower-Valves-Rebuild-or-Replace-300x169.png\")