I've noticed the markings on my rear wheel cylinders (9" Sierra Drums) are different from one side to the other. One is marked NT01, the other NS07.

Is there a difference between these (different size cylinders for example?) or are these just batch numbers or something?

bump. Anyone got any idea what the numbers mean?

Got me curious, went and had a look at mine - the old ones - 1993 sierra - are marked
FC2 759 and on the other side 3145 22
FC4 959 and on the other side 3145 22

As they are ten a penny, I bought some replacement ones a couple of months ago -
Marked -
4 LO 10
6 LO 10

As to what they mean?


No Idea.

Sorry.