What to Know About Fixing a Noisy or Loose Seiko Rotor

One of the most common issues that Seiko watch owners encounter is loose rotors, especially when it comes to the Monster or SKX models. That stems from a flaw in the overall initial design, far removed from any Seiko mods. A loose rotor is typically characterized by a rattling noise that’s unusual, especially when compared to the typical spinning sound.

Mechanical watches have parts that can be swapped out with a number of Seiko mod parts but in terms of base components, the automatic rotor is downright indispensable. It allows for the automatic winding of the watch as the wrist of whoever is wearing it moves about. 

When there’s a loose rotor issue, the best case scenario is that the case back or movement will have some scratches. The worst case scenario, however, is that it devolves into something tricky such as the watch stopping altogether due to damage that is far beyond repair.

What is the best way to address a loose rotor?

To begin with, the wearer needs to be certain that the rotor is loose in the first place. Simple observation can already go a long way. Shake the watch a bit and listen closely to the sound it makes. When there’s a scraping sound (particularly a metallic one that indicates scraping of the case back or movement) then the chances of a loose rotor is very likely.

It should be noted that sounds while winding is happening, especially for Seiko’s 6r15 and 7S26, are actually quite normal. However, a loose rotor sounds nothing like spinning does. A regular sound is more along the lines of smooth mechanisms.

Watches with a display case back have a slight advantage in this case. Shake the watch gently then look at the rotor and see if it’s moving freely like it always has, or if there is a noticeable shift. Of course, it is possible that just looking at it will not help determine whether or not the rotor is loose.

What other way can the loose rotor be checked out?

Gather tools such as a screwdriver, a case back opener, and a pegwood/finger cot. You could also opt for a threadlocker. Then remove the case back, look at the rotor, tighten the screw, and if necessary loosen said screw in order to apply purple Loctite. Of course, after that, it’s key to do a final sweep in order to check it out as a whole.

It is possible for the rotor to loosen yet again, since the screw has a tendency to turn alongside the still-oscillating rotor. This is where the purple Loctite 222 application comes in, or any similar threadlocker that can get the job done.


There are a few issues that certain Seiko models face, such as the SKX or Monster. This includes a loose rotor, which is something that can be traced all the way back to the initial manufacturer’s design as a whole. It can be found out for certain either through observation or by carefully removing the back case to take a good look.

Are you looking for Seiko mod parts in the UK? Shop at SeikoMods today! We are the crystal specialist to go to for Seiko sapphire crystals, as well as cases, casebacks, bezels, bezel inserts, crowns, chapter rings, dials, movements, and other associated metal parts.

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