oldretiredafguy
Full Access Member
- Joined
- Apr 20, 2020
- Posts
- 1,417
- Reaction score
- 3,221
- Location
- N. Texas
- First Name
- Mike
- Truck Year
- 1988, 1988, 1991, 1983
- Truck Model
- GMC V-Jimmy, GMC Suburban 4WD, GMC Suburban 4WD, GMC-2500 CrewCab
- Engine Size
- 350, 350, 350, 350
I put together this little cheat sheet for taking to the parts store. Don't trust most of them to look up the correct application, then be able to discern what their 'puter' says.
JB1 JB3 JB5 JD3 JD5 Brakes
JB3 is the 1" thick rotors
JB5 is the 1.25" thick rotors
There are 2 style calipers and rotors on these trucks after 1980, Standard 1" and HD 1.5" They don't interchange.
For 1/2 Tons..
JB1 - manual brakes, 1" rotors
JB3 = power brakes, 1" rotors
JB5 = power brakes, 1.25" rotors
JB1 BRAKE, MANUAL, DISC/DRUM, 4300 LBS
JB3 BRAKE, POWER, DISC/DRUM, 4600 LBS
JB5 BRAKE, POWER, DISC/DRUM, 6400 LBS
JB6 BRAKE, POWER, DISC, DRUM 7200 LBS
JB7 BRAKE, POWER, DISC, DRUM 8400 L85
JB8 BRAKE, POWER, DISC, DRUM 10000 LBS
The only rear ends that have 13" brakes are the JB7 and JB8 brakes on a 14 bolt full float.
JD5: Brake, Dual Power, Disc/Drum, 6,400 Lbs GVW (Dual Diaphragm Vacuum Booster)
JD6: Brake Hyd Power, Disc/Drum, 7,200 Lbs GVW (Hydro-Boost Booster)
JD7: Brake, Hyd Power, Disc/Drum, 8,400 Lbs GVW (Hydro-Boost Booster)
10 or 12 bolt [rear axles] had either 11.15" x 2.75" for the JB5 or 11.15" x 2" for the JB3.
Hope this helps someone.
JB1 JB3 JB5 JD3 JD5 Brakes
JB3 is the 1" thick rotors
JB5 is the 1.25" thick rotors
There are 2 style calipers and rotors on these trucks after 1980, Standard 1" and HD 1.5" They don't interchange.
For 1/2 Tons..
JB1 - manual brakes, 1" rotors
JB3 = power brakes, 1" rotors
JB5 = power brakes, 1.25" rotors
JB1 BRAKE, MANUAL, DISC/DRUM, 4300 LBS
JB3 BRAKE, POWER, DISC/DRUM, 4600 LBS
JB5 BRAKE, POWER, DISC/DRUM, 6400 LBS
JB6 BRAKE, POWER, DISC, DRUM 7200 LBS
JB7 BRAKE, POWER, DISC, DRUM 8400 L85
JB8 BRAKE, POWER, DISC, DRUM 10000 LBS
The only rear ends that have 13" brakes are the JB7 and JB8 brakes on a 14 bolt full float.
JD5: Brake, Dual Power, Disc/Drum, 6,400 Lbs GVW (Dual Diaphragm Vacuum Booster)
JD6: Brake Hyd Power, Disc/Drum, 7,200 Lbs GVW (Hydro-Boost Booster)
JD7: Brake, Hyd Power, Disc/Drum, 8,400 Lbs GVW (Hydro-Boost Booster)
10 or 12 bolt [rear axles] had either 11.15" x 2.75" for the JB5 or 11.15" x 2" for the JB3.
Hope this helps someone.