Why Moen Shower Knob Keeps Breaking [5 Easy Solutions]

Moen shower knobs or handles are not only to regulate the pressure and temperature of the water. These days, they also enhance the outlook of your bathroom with elegant designs and materials. But one of those designer single knobs’ biggest disadvantages is they have a pretty complex and sensitive mechanism. 

A very common complaint we hear is that a Moen shower knob keeps breaking even if it’s not very old. Well, the probable reasons are rough valve movements, faulty installation, use of worn-out parts, excessive water pressure, etc. Sad but true, you can’t fix a broken shower knob no matter what the reason is. 

In any case, replacing a shower knob and fixing the shower system to make sure no shower equipment gets damaged sooner than expected is the best solution. So today, let’s say something about the reasons causing broken shower knobs. 

Why Moen Shower Knob Keeps Breaking [5 Easy Solutions]

Moen is one of those bathroom-fitting brands that you rely on with your eyes closed. But sometimes, they also fail to last longer due to very small issues. Below here, we’re focusing on those issues that we often forget and cause broken shower knobs. 

Note: You can also read how to deal with Moen Shower handle stuck.

1. Overtightening

When you overtighten the handle valve or the central screw of the handle, your knob becomes stiff at one point. Trying to move or twist a hard-to-turn knob ends up in a broken handle system. 

New DIYers don’t know exactly how much you need to tighten the knob. They can overdo things for fear of getting leaks or loose control over the water flow. Which ultimately backfires and ends in stripped screw threads or broken handles. 

Solution:

• When you install a new shower handle, make sure you’ve installed the cartridge lubed. 
• Make the main screw go deeper through the knob unless the knob becomes stable enough on the spot to get twisted without shaking.

2. Mineral Deposit

Hard water and leakage cause mineral deposits in the shower system and pipings. The most affected area by mineral deposits is the central valve where water pressure, flow, and temperature get regulated. 

Hard water can quickly create layers of calcium and other minerals or metals that can fill the gap between the internal parts for smooth movement. Mainly, the buildups can make the handle movement rough. That’s why when you put extra pressure to turn the knob, it breaks. 

Solution: 

• Turn off the main water supply.
• Bring out the handle valve with related accessories. 
• Take a large bowl filled with 1:1 edible vinegar and water mixture. Put the valve, cartridge, and other stuff inside the mixture. Wait for at least 30 minutes.
• Now, bring those things out of the mixture and rub them with an old toothbrush to remove stubborn buildups. 
• Install everything back and the shower valve is ready to have a new handle without any issues. 

3. Lack Of Grease

We often forget that greasing is required in some plumbing cases too. You need to use the “plumbers grease” to install a cartridge into the valve. If you haven’t used any water-grade grease, friction around the cartridge would break or damage the handle or knob construction. 

Moreover, you should know that grease layers wear off after a certain period. If there’s no lube layer left in the valve, a new handle would hardly work and break soon. 

Solution:

• Put off the nickel plate from the wall and take off the cartridge from the inside. 
• Lube the cartridge exterior with WD-40 or any similar product. You can also lube the housing of the valve and the new handle’s interior. 
• Put everything back and install the new handle. 

4. Excessive Water Pressure

In a residential space, the water pressure should be around 40-70 psi. But when the pressure level reaches around 80 psi, there’s a possibility of regulator valves of bathroom and kitchen fittings getting damaged. 

Here, the regulator valve is actually the main valve under the handle or knob. They can regulate the average water pressure to let you use water comfortably. But the extra pressure slowly damages the valves and water outlets. 

Besides, extra pressure causes leakage in the handles too. And water leaking is the main reason for corrosion and mineral buildup. So, one way or another, excessive water pressure is very dangerous for the shower knobs. 

Solution:

• Check the main power line and make sure the mother valve is set for below 70 psi supply. Just loosen the valve screw to drop the water pressure.
• There are two separate inlets for the hot and cold water lines. Make sure they are in the same position and they are having decent pressure.
• You can use a pressure regulator with the main valve to keep the water pressure in the ideal range. 
• If you don’t have anything to measure the water pressure or don’t know where the main valve is, you better call a plumber. 

5. Corroded Or Worn Out Parts

After 6-10 years of use, shower handle accessories and parts can get rusty and corroded due to unwanted oxidation reactions around. Along with that, rubber products like washers and O-rings wear out because of consecutive use. 

Any shower set element can get corroded or worn out after years of regular use. They can also wear out sooner than the expecting period. However, rusty or worn-out parts easily get broken. That’s why you can see your shower handle keeps breaking or falling off even if the handlebar is new. 

Solution:

• You need to avoid using heavily corroded or worn-out parts with the new handle. Replace corroded parts with new OEM ones. 
• If you see any area starting to get rusty, use lime water to rub the area and stop the oxidation. 

How To Fix A Broken Moen Shower Handle

At the very beginning, we’ve said that the only way to fix a broken shower handle or knob is to replace the broken part with a new one. Nowadays, you can find any type of OEM product in a very reasonable price range. No matter which model or brand you’re using, you can find replacement parts of that shower set in your nearby store. 

When you see your shower knob is broken, you can remove the plates and covers to reveal the whole valve area. You can inspect every corner of the valve, cartridge, washer, O-ring, and handle when you separate them from each other. 

If you find anything that can barely work or doesn’t seem to be okay, don’t hesitate to replace it. There’s no need to replace the whole setup. Apart, here are some facts to keep in mind when you’re fixing a broken shower handle:

Key Considerations:

• Don’t forget to turn off the bathroom’s supply valve before starting to work. 
• Bring out the handle and cartridge along with the valve and soak them in a vinegar mixture before replacing anything. Then rub them with a soft brush and see which parts can work further. 
• Anything that has cracks or corrosions must need replacement
• Use an adjustable spanner or wrench to tighten or loosen the cartridge or sleeve. 
• Always remember to put plumbers grease over the cartridge and handle core before installing. 
• If possible, buy universal models for replacement. 
• Lastly, check the tightness of the handle when you install one. 

FAQs:

Summary

We all know the old proverb that prevention is better than cure. As you can see, if a shower knob is broken, there’s nothing left except changing the damaged area and taking action so that the new setup doesn’t break. 

We’ve pointed out every possible reason that causes shower knobs to break suddenly. You should follow the ways mentioned above to make sure your new shower handle will last more than a decade without requiring any major change. Still, if anything seems unfamiliar to you, don’t hesitate to reach us.