Which brakes, JD6/JD7?
 

On my 1986 K20, I need to replace nearly every brake componenet except the booster and MC. I looked up the calipers, and I get the option for JD6/JB6 or JD7/JB7 brake system. The description says it'll show on the RPO label in the glovebox, but that is long-gone. Does one code mean a certain size rotor, or something you can visually tell? Thanks.

-adam

Re: Which brakes, JD6/JD7?
 

Normally the best way to id your brake option is the thickness of rotor and the width of the rear shoes. I don't know what codes correspond to what size, but the parts stores normally can match up with rotors and shoes.

Re: Which brakes, JD6/JD7?
 

The rotors on both systems (JB6 & JB7) are the same dimensions. However, the dimensions of the rear drums are different. The JB6 drums are 11.15 x 2.75 whereas the JB7 drums are larger at 13 x 2.5.

Re: Which brakes, JD6/JD7?
 

Thank you for the info guys....when I look up the part number on the calipers for JB6 and 7, they are different. Any clue what the difference is?

Re: Which brakes, JD6/JD7?
 

cause the front rotors are either 1 inch thick, or 1.25 inches thick.

Re: Which brakes, JD6/JD7?
 

Actually, the thickness of the rotors are the same for both systems. The difference is that the JB6 is a low drag system and the JB7 is a conventional brake system.