Looked all over the master, there are no size markings. Just the following: What appears to be 6E10 NS4 on the front and on the bottom it says Aisin.

I tried to measure it, theres a snap ring in the way, measuring outside of it I get roughly 1.17 inches which seems way to large. Measuring inside the snap ring gets me 1.063 which is 1 1/16". So it would appear I have the larger master I think. I mean unless I take it all apart it seems I wont know for sure. Im just gonna buy the smaller one, I suppose I can always exchange it.

Going to call toyota as well and see what they can tell me.
Edit: Call yota, they can only tell me truck is spec'd for 1/2 ton master. IDK..

Also: The master shows no outward signs of leaking at all, cant tell if its leaking internally.

The booster, when you grab the pushrod air escapes-normal?

Last edited by CJMT100; 03/19/13 08:39 PM.

1996 T100, Mickey Thomson Classics, Bridgestone Dueler AT 265/75/16, custom offroad KC's.