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speedygonzales · 06-28-2014, 09:29 AM

Ok I have JB5 system and lookup says they are 6400 Lb.
Here's a picture
http://i1371.photobucket.com/albums/...g?t=1403961476

Only thing I see is the "DA" sticker. So what do I have? And how do you figure it out? I didn't see anything that explains the types of diaphragms. How does the types relate to the RPO code?

I see JB8 says 10000 Lb

That must be Hydraulic.

I found this on a bulletin board
JB5= front disc 11.86X1.29 rear drum 11.15X2.75 Vacuum-Double Diaphragm

JB7= front disc 12.50X1.54 rear drum 13.00X2.50 Vacuum-Double Diaphragm

JB8= front disc 12.50X1.54 rear drum 13.00X3.50 Hydraulic-Hydro-Boost

But how do you get part numbers for these boosters.

Then there is this:
http://www.oreillyauto.com/site/c/de...1305&ppt=C0066

It says it's 10.75" and used for JB5,6&7???? I don't get it.

Do I want the one that is 13" x 2.5? Do you look for the booster from a 1 ton truck?

06-28-2014, 09:29 AM	#84
speedygonzales Registered User Join Date: Jan 2006 Location: Smithfield, VA Posts: 1,501	So what type do I have? Ok I have JB5 system and lookup says they are 6400 Lb. Here's a picture http://i1371.photobucket.com/albums/...g?t=1403961476 Only thing I see is the "DA" sticker. So what do I have? And how do you figure it out? I didn't see anything that explains the types of diaphragms. How does the types relate to the RPO code? I see JB8 says 10000 Lb That must be Hydraulic. I found this on a bulletin board JB5= front disc 11.86X1.29 rear drum 11.15X2.75 Vacuum-Double Diaphragm JB7= front disc 12.50X1.54 rear drum 13.00X2.50 Vacuum-Double Diaphragm JB8= front disc 12.50X1.54 rear drum 13.00X3.50 Hydraulic-Hydro-Boost But how do you get part numbers for these boosters. Then there is this: http://www.oreillyauto.com/site/c/de...1305&ppt=C0066 It says it's 10.75" and used for JB5,6&7???? I don't get it. Do I want the one that is 13" x 2.5? Do you look for the booster from a 1 ton truck? __________________ 99 Z71 (98 body style) Pride and joy Last edited by speedygonzales; 06-28-2014 at 09:45 AM.