Por lo que he leido en el foro, tambien deberias hacerle la "prueba del viscoso" segun aparece en:
http://www.ashcroft-transmissions.co.uk
To check the condition of your unit :
1) put in 1st gear 2) Handbrake off 3) Jack up one rear wheel 4) the wheel should turn slowly with resistance
Note even a good one will be quite tight. A siezed one will feel like the handbrake is dragging when reversing slowly on full lock.