This spring has two legs which engage in the slot in the regulator spindle. It is 0.945”OD and it fits into a housing which is 0.899” ID. It binds in the housing and friction prevents the drop glass from being pushed down from the outside, which is easy if the spring is broken or missing. On my car one of the legs of the spring had broken off. A repair had been attempted. The housing had been removed from the base plate, the broken spring reinstalled for want of a replacement and the housing tack welded back to the base plate.

I searched for a new spring and noticed that the Morris Minor has a similar regulator mechanism, although smaller. However the spring is identical! Problem solved.

CP-112 uses a cut down Magnette segment gear but the segment in the Minor is identical to that in the MGA and probably more readily available. The two mechanisms are shown in the picture with the Minor at the bottom. The center picture shows the Coupe spindle with Minor spring in position.



Having seized long ago, the pantograph rollers that run in the window channel had worn flats on the head of the pin and on the wheel. I used the Minor components for one roller and made a new wheel for the other, a disc of 0.040” steel pierced 3/8” and squeezed into a 15/16” socket on the ball end of a ball pein hammer [and trim to 3/4" OD after forming]. I turned the pin through 90 degrees to present an unworn surface to the channel. The pin ends were welded to the pantograph bar and the welds ground flat.

Addendum April 30, 2019:
Mark Wellard had a different technique. "Instead of welding the spindles back in place, I tapped the spindles and screwed them into position with 3/16-inch pan head screws that had the heads reduced in size for clearance".

The pins that secure the winder and door handles are easily removed if the bezel is pushed down with the tool shown. The door is more readily removed and replaced if pins as shown are screwed in as the hinge screws are removed. The longer pin with a spring is used to grab the top of the door for single handed removal and fitting of the door without damage to the paint.