how to identify what brake setup I have?

[G-NUT]

Hi guys.  I would like to know if there is a way to identify, or maybe you can tell me, what brake setup I have.

The truck is a 1985 GMC Sierra Classic 2500 crew cab LWB.  The brake booster looks pretty big.  I was wondering if someone knew off hand what size rotors / calipers I might have?  I have not taken the wheel off to physically lay eyes on them yet.  I downloaded off this forum a 1984 and 1986 factory manual.  There are some brake codes in there but I don't know where on my truck to identify them.  I decoded the VIN, but all it tells me is that it's a hydraulic brake system, which I knew.  The truck did come with some factory optioned tow package as identified my a label in the glove box.

Thank you.

[zieg85]

The sticker in the glovebox will tell you what you have if it is still there and original to the truck.  Other than that I think the 3/4 Ton front brakes are the same and the rear shoes will be based on which rear end.  If it has a full float or semi float 14 bolt corporate.  Engine size should tell which on you have if it is original to the truck.  Diesels and 454 equipped trucks had the full float where the hub sticks out in back where the other looks similar to a car rear end where the brake drum slides off if that makes sense

[Irish_Alley]

http://forum.73-87chevytrucks.com/smforum/index.php?topic=28592.0