Servicing the Ford Fiesta

Like it or not, we live in a global economy.  Products that international corporations sell in the United States also have to be sold in other countries around the world.  This “globalization” has brought locksmiths a lot of good things and bad...

With the cover off, you can see the lock housing in Photo 25.  If you have to buy a replacement lock for one of these, it will not include the plastic cover, since that is painted to match the car.

At the rear of the lock, Photo 26 shows the cam and the push-on fattener that holds it in place.  When I first saw this fastener, I was shocked, because I’m used to more easily serviced fasteners.  However, after looking at the lock and the way that it fits into the latch, it’s clear that even if this fastener came loose or fell off, the lock would still work.  This is because the cam is trapped between the latch and the back of the lock.

The easiest way that I found to remove the push-on fastener was to use an offset scribe to lift the individual tabs.  (Photo 27) After lifting only two or three tabs, the fastener comes off easily.

Before you replace the fastener, re-straighten the tabs so that they will hold onto the shaft tightly. (Photo 28)  I did this by placing it on a flat surface and then I pressed each tab down flat with a large screwdriver.  As soon as I saw this push-on fastener, I began to suspect that this lock was not intended to be serviced.  I recommend replacing the lock rather than attempting to service it, unless you have no other choice.

After the fastener is out of the way, the cam will lift off of the shaft.  Like most modern high security door locks, the Fiesta door lock is equipped with a clutch that will allow the lock to freewheel without unlocking the door if too much pressure is applied.  The driver, or clutch plate for this system, is located directly below the cam. (Photo 29)

The driver will lift off the shaft easily after the cam has been removed.  Note that the driver has a tab that fits into a slot on the tail-shaft of the lock.  (Photo 30) When the clutch has been activated, this tab will be pulled away from the shaft allowing the lock cylinder to turn without turning the driver or the cam.  Also note the curved slot on the underside of the driver.  The end of the clutch pin fits into this slot so that the lock turns freely under normal conditions, but when the clutch has been activated, the clutch pin will pull the driver free of the tail-shaft.

With the clutch plate out of the way, Photo 31 shows the clutch pin.  Just as on the new GM “freewheeling” locks, this pin rests in a slot on the side of the lock cylinder and locks the cylinder into place.  However, instead of being backed with a rubber pad, this clutch pin has two “wings” that rest in slots in the lock housing.

When we pull the clutch pin out of the housing, Photo 32 shows that the “wings” are slightly curved so that the pin will only fit into place in one orientation.  The entire pin assembly is made of a cast material that is not flexible.  If too much force is applied to the cylinder, the wings on the clutch pin will break off, allowing the pin portion to be pushed up out of its slot.  This will in turn pull the clutch plate free of the tail-shaft and allow the cylinder to freewheel without unlocking the door.

With the clutch pin removed, we can see how the cylinder can rotate. (Photo 33) Since this type of clutch actually breaks when it is activated, the lock will have to be serviced before it can be put back into service.  At the time I am writing this, replacement clutch pins are only available as a part of a new lock set.  That may change in the future, but until then, the only repair for a lock that freewheels is a complete replacement.

We are now ready to remove the lock cylinder from the housing.  The cylinder is held in place with two small steel tabs that are driven into a slot in the lock housing.  The slot is only open on one end and after the tab is inserted, the top of the slot is staked over to hold the retaining tab in place.  In photo 34, you can see the tops of both tabs marked with the arrows.

The only effective way to remove the retainers was to drill two small holes on the opposite side of the lock into the retainer chambers.  Then I could insert a punch and drive the retainers out of the slots.  The drill points will have to be determined by eye, and are indicated by the arrows in photo 35.

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