PART NO.  SPL.PAGE  DESCRIPTION                                                           
80641     15.M.4    Spring -pawl rod -(handbrake, 1500)
80641     TC.M.4    Spring -pawl rod -(handbrake, Twin Cam)
80641     16.D.7    Spring -pawl rod -(handbrake, 1600 and 1600-MK-II) -changed to AAA515
AAA515    16.D.7    Spring -pawl rod -(handbrake, 1600 and 1600-MK-II) -was 80641

Image at right compliments of Mark Campbell in Grimsby, UK -- This spring fits inside the MGA hand brake lever for thumb button return. Imperial dimensions are:

O.D.	0.375"
Free Length	2.250"
Wire Diameter	0.051"
Number of active coils with closed and ground ends	30

Alternate numbers:
BMC no. 80641, AAA515
Moss part number 181-250 *
  (for 1500, 1600, MKII)

*Note: The spring supplied by Moss Motors (at time of this posting) is incorrect with 0.485" dia x 3" long with smaller wire diameter and only 10 active coils. It appears to fit under the edge of the button rather than inside the button. Picture at right is an oil pressure release spring, and the incorrect Moss thumb button spring.

Picture at right is a broken original thumb spring and a new incorrect one from Moss Motors. Not know at this time if it works or not.