Fixing a Sticky Moen 4570 Monticello Faucet

Jonathan Taylor
jonathan at

Our house, which was built in the early 1990s, came equipped with not one, not two, but seven of the Moen model 4570 faucets. To my untrained eye, these seem like fine faucets that are likely to last a long time, but they've all had one fatal flaw: Over time, the handles of the faucets became harder and harder to turn, until the faucet finally became nearly impossible to use.

One of my Moen 4570 Faucets.

His Eminence, the Elbow

Some trial-and-error investigation led me to realize that the problem lay in the "elbows", not the faucet cartridges themselves. In Moen-speak, the elbows are the big round decorative pieces that sit on top of the sink, to either side of the spout, from which the handles protrude. When the faucet is working properly, the handle turns the top part of the elbow, while the bottom part remains stationary. With our faucets, these two parts had become fused together, making the handle very hard to turn.

It appears that 15 years of hard water deposits and soap residue had built up in the moving part of the elbow, leaving it badly corroded and very stiff. The simplest and most obvious solution was to replace the elbows with new parts from Moen. I checked the model number of the faucet (4570, stamped on the back of the spout) and looked up replacement parts on the Moen Web site. But the price was painful -- around $75 to $125 per elbow, depending on the finish. Fortunately, I discovered that it is fairly easy to take the elbow apart, clean it, lubricate it, and put it back together. This Web page describes the procedure, for the benefit of anyone else who might be having the same trouble.

My disclaimer: I am not a plumber, nor do I work for Moen. But I did stay at a Holiday Inn Express last night.

Since we're not replacing the cartridge, it actually isn't necessary to turn off the water supply. The first step is to unscrew the elbow from the rest of the faucet. If you're lucky, you can do this by hand, just by grabbing the body of the elbow and turning counter-clockwise. Since the threads of my faucets were corroded too, I found it necessary to grip the body with a strap wrench (above the sink) while holding the faucet body with an adjustable wrench (under the sink), then give the strap wrench a good hard turn.

One word of caution: While unscrewing the elbow, hold the handle of the faucet in one position, if you possibly can. If the handle is allowed to turn as the elbow is being un-screwed, it can shear off the plastic stem extension inside the elbow. If you do break this plastic piece, you can order an inexpensive replacement kit from Moen; part number 97479. The replacement kit has a red stem for the hot side and a blue stem for the cold side; they are not identical, but mirror images of each other.

After removing the elbow, unscrew the screw inside of it that fastens the top part to the plastic insert. Although this screw was easy to remove, it was very difficult to separate the top part of the elbow from the body once the screw was taken out. I found that a good way to separate the two pieces was to use a hole saw to cut a large hole in a piece of wood slightly smaller than the diameter of the elbow, then place the elbow upside-down in the hole. This becomes a jig that holds the body of the elbow in place but allows the top part to come loose. Put a long nail into the screw hole, and tap it a few times with a hammer. The top piece of the elbow will eventually come off.

The photo shows how much crud I found in the three pieces of the elbow. Yuck. As you can see, the bright brass finish is starting to peel, too.

I used a wire brush to remove the corrosion, including the threads of the inside of the elbow, and the threads of the body of the faucet itself, to make the elbow easier to screw back on. Before putting it all back to together, I found that it turned even more smoothly if some WD-40 was sprayed inside the elbow body. Insert the plastic piece into the elbow body, then re-attach the top part, noting that it fits on just one way due to a wide space in the plastic ribs. It may be a tight fit, especially if the fluting inside the top piece is corroded, so you might need to use some force to push it in. To replace the screw, I found it handy to hold the screwdriver upside down, put the screw on the tip, hold the elbow upside down over it, and then carefully raise the screw into position.

Test the handle to be sure it turns smoothly and easily, and then screw the elbow back on to the faucet body. Remember this procedure, since you might need to do it again in another 15 years!