SEKISUI (SEKISUI) lock case WEST C55 (5200) Disassembly inspection and repair due to malfunction of the main unit

"There is a sense of incongruity, and there are times when the key does not turn."

It is a detached house purchased at a second-hand property several years ago. It seems that the cylinder was replaced at that time, but there were times when it got stuck and did not turn, so I got worried and called.

It was a wise decision to make the decision to call before it became a serious matter, such as being locked out or confined.

A few years ago, the client had a local locksmith take a look, but it seems that she was told to ask a construction company that handles SEKISUI because that locksmith guy couldn't handle it. Sounds like your inspection wasn't good enough.

There is only "SEKISUI House" engraved on the front of the lock case. Most of them are OEM of WEST, so they are C55 (5200) type lock cases.

Replacement cylinders are WEST917-GFA52 or WEST916-GFA52.

The lower cylinder seen in the photo is a dummy cylinder. It is unusual for this type to have a dummy cylinder.

Well, when I disassembled it, there was no wear or damage to the parts of the lock case.There was a sense of incongruity in the movement around the deadbolt, so I was able to improve it by cleaning and lubricating around the link mechanism.

The assembly around the spring is complicated. Does it need to be this complicated? Anyway, reassemble after cleaning and you're done.

There was interference between the deadbolt guide on the upper cover and the square cam stopper on the deadbolt, which could be said to be part of the design problem, but we decided to see how it would go without additional work on the corner radius.

If the client were to speak to Sekisui Heim, it would be called a door replacement (there was also a case where the same thing was said before. I was surprised at Sekisui's bullish sales. I think it's a good business policy, but...), but she found out that it can still be used in active service, so she was relieved that it was "good".

By the way, the set model number is the old WEST171 lever handle lock.