hi, i have a 1983 gmc suburban 2wd with the 5.7, just got it today.

the brake booster is bad on it and when i called advance to order the new one they told me that there were 2 different brake systems for my truck and i needed to know which one i had.

they said there should be a sticker in the glove box with that information, which was missing from mine.

is there any other way to figure out which booster i need to order?

 

Is there a part number on it?

 

Give your VIN to your parts dept. I think they can ascertain what you have.

 

i did some more research today and think i figured it out, for my application there was a jb5 or a jb7 brake system available, or at least, that's what's available from advance. they are interchangeable but you have to swap the master too. looks like the jb7 is the heavy duty one.

JB5= 6400lb. disc 11.86X1.29 / drum 11.15X2.75 Vacuum-Double Diaphragm
JB6= 7200lb (K20 and others)
JB7= 8400lb. disc 12.50X1.54 / drum 13.00X2.50 Vacuum-Double Diaphragm
JB8= 10000lb. disc 12.50X1.54 / drum 13.00X3.50 Hydraulic-Hydro-Boost


above is what i pulled from a google search, i wonder if the larger rotors and calipers can be interchanged also...

 

you can look at the codes in the glove box if it still has the sticker in there. if you have a hydro booster then youll have power steering lines going to the booster. for the vacuume booster itll have one vacume line going to it