Delta Monitor shower faucet low water pressure

Recently, my old plumbing decided to choke up a round of sediment, wreaking havoc on all the little holes in my plumbing fixtures.  Now the shower has very low water pressure, this time would be round two of clearing out the cartridge – but of course nothing goes as planned.  The faucet is a standard Delta Monitor, which I’ve successfully replaced the old Cartridge for previously.

But of course, this time it appeared that the set screw to remove the handle had been stripped…

I tried letting it rest in some WD-40, difficult to do when its horizontal… none of this seemed to help and I just wanted it off.  I saw my only choice as to start the process of trying to remove the set-screw with other means:

  1. Try using some extractors, like this set
    • They will have a specific size of hole intended for you to drill.
    • You’ll have to drill a bit deeper of a hole then the current set-screw socket.
    • These bight by reverse-thread which once embedded should turn the set-screw in a counter-clockwise direction to remove it.

I was able to get them into the set screw, but they flexed pretty good when tourqued out, this set screw was frozen. My only recourse at this point was to drill out the set screw.

  • Start smaller to see if you can get away with not ruining the handle.
  • I used some cheap hex-bits so I could use an extension driver for the power drill – otherwise there’s no way to get to the hole.
  • The largest size bit which was almost the diameter of the set screw finally allowed me to release the handle.
  • Turns out I went all the way through the set screw and partially into the thread extender.


Now onto removing the cartridge, once you remove the retaining ring and pull it out you’ll probably see obvious sediment.  Next, you’ll need to turn the water supply back on (close your shower curtain) and let it blow out the valve for a few seconds (could make a mess).  Then you can just clean out all the debris.

  • The chrome sleeve should just pull off – you should have removed this already.
  • Use large channel-lock pliers to unscrew the brass retaining ring.
  • You’ll probably have to pull and wiggle pretty hard to get the cartridge out, depending on how solid the whole mixing valve is this may be troublesome.  Work on pulling directly out vs too much lateral movement.
  • Trying to twist can help.
  • Optionally you could turn the water back on (with the faucet in the OFF position) and see if the pressure will blow it out – I didn’t try that.
Cartrige Ends – obvious sediment in the screens.

At this point you have a few decisions based on the condition of your mixing cartridge.  The first time around I ended up buying a whole new one based on the age and amount of sediment.  The second time, it had been about a year or two, I decided to replace the o-rings as they were a little chewed up from install/pulling out the cartridge:

Obviously, I stripped my handle set-screw, so you’ll want to get a replacement handle.  The H79 was the plain straight one, while this RP17443 was an akward one that mounts as an angle.


1 thought on “Delta Monitor shower faucet low water pressure

  1. Garrett,
    Really appreciate the site, I have the exact same issue. Just ordered the set of extractors.


    Nick DeVito

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