JB7 with JB8 calipers??

[DuallyBurb]

Alright guys...I've done my research and have come up empty. I have a Frankenstein 77 Suburban. Its a " trailering special" and has a Dana 70 dually rear end with 13" rear brakes. It has JB7 master and booster with normal 1\2 ton front brakes(5 lug). Upgrading to 1 ton front suspension components with dually front rims. Here are my million dollar question(s).

The spindles and calipers I have for it are for a JB8 system. I do not want to do a JB8 conversion of my whole system.

Can I just hook up the JB8 calipers and will they even function safely and\or properly?
 

Are JB8 calipers incompatible with a JB7 system?

Do I need to upgrade other braking components?

Are there 1 ton spindles dually spindles that utilize JB7 calipers and pads?

 I have good pedal travel and braking power right now although it noticeably does take effort to push on the pedal compared to other older trucks I've driven that have jb5 or jb6 systems.

This truck will be used to tow the majority of the miles that are put on it.

[Irish_Alley]

ok jb7 uses a cast reservoir and its gvw is 8400lbs. ½ton truck should use a plastic reservoir. (jb3,5 and 6). JB7 and JB8 use two different cast reservoirs, idk if they are interchangeable or not. but do you have hydro boost?

[DuallyBurb]

The truck does not have hydroboost. It has a JB7 system. It was converted over by the dealer when the rear dually Dana 70  axle was installed with the 13" rear drum brakes. It is a "trailering special" optioned Suburban from the factory. Factory option code Z82 I believe.

[Engineer]

You can run the JB8 calipers.

DO NOT mismatch the JB7 calipers with JB8 calipers. The difference is the diameter of the caliper piston. The bigger the piston the more braking force you have. A mismatched set of calipers will cause your truck to veer in the direction of the larger caliper when braking.

[enaberif]

ok jb7 uses a cast reservoir and its gvw is 8400lbs. ½ton truck should use a plastic reservoir. (jb3,5 and 6). JB7 and JB8 use two different cast reservoirs, idk if they are interchangeable or not. but do you have hydro boost?

Are you sure on this? I thought all reservoirs for our trucks were cast? I have JB5 brakes and a cast master cylinder.

[Irish_Alley]

ok jb7 uses a cast reservoir and its gvw is 8400lbs. ½ton truck should use a plastic reservoir. (jb3,5 and 6). JB7 and JB8 use two different cast reservoirs, idk if they are interchangeable or not. but do you have hydro boost?

Are you sure on this? I thought all reservoirs for our trucks were cast? I have JB5 brakes and a cast master cylinder.

gas or diesel? i dont know for sure but from the research ive done (and i could be wrong for other years) but a gas ¾ ton will have a plastic if its jb3,5 or 6 a gas jb7 will have a cast. diesels ld3,5 and 6 will have cast and the jd7 is the same as the jb7.

would like to know for sure so im not giving out bad info

[enaberif]

Mine is a gas truck. I was pretty sure plastic didn't come into the trucks into the mid 80s. I looked at Rock Auto and they show plastic for 84/85.

[Irish_Alley]

this maybe very true i know my 86 has plastic. just looked it up when i did my "research" i guess i was going off the newer style cause i knew what they had and didnt think about the years. thanks ill get capt to fix the tech page

[Irish_Alley]

81 was the first year for the plastic. but theres a lot more types pre 81 that i need to fix

[Irish_Alley]

think its fixed now
http://forum.73-87chevytrucks.com/smforum/index.php?topic=28592.msg238566#msg238566