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73-87 Chevy _ GMC Trucks => Brakes, Frame, Steering & Suspension => Brakes and Braking Systems => Topic started by: SpartanTravis on April 21, 2015, 08:26:39 am

Title: JB5 or JD5 Brakes???
Post by: SpartanTravis on April 21, 2015, 08:26:39 am

I have an 84 K10 I'm pretty sure I have a vacuum brake booster.
(http://images.tapatalk-cdn.com/15/04/21/4f2bb06be3ed541c330451bfbf60dd8c.jpg)

I'm trying to find out if my brake booster is a JD5 or a JB5. If anyone knows, please help me out. I have none of the identification stickers in the door jam, glove box, etc.

Here is my vin in case it help.
2GCEK14H1E1141337


Thanks,
Travis

Title: Re: JB5 or JD5 Brakes???
Post by: enaberif on April 21, 2015, 08:35:49 am

http://forum.73-87chevytrucks.com/smforum/index.php?topic=28592.0

Title: Re: JB5 or JD5 Brakes???
Post by: SpartanTravis on April 21, 2015, 10:16:26 am

Thanks enaberif. So if I have a JB5 then I have to have the rotors and calipers to match correct?


Thanks,
Travis

Title: Re: JB5 or JD5 Brakes???
Post by: enaberif on April 21, 2015, 10:49:27 am

Not necessarily but its best to keep the system the way it was.

Title: Re: JB5 or JD5 Brakes???
Post by: Irish_Alley on April 22, 2015, 03:20:12 am

if i had to guess i would think JB3. JB3 is for gvw of 4600lbs, while JB5 is for 6400lbs. the highest a ½ ton truck went to was 6200 and that was on the "BIG TEN".

Title: Re: JB5 or JD5 Brakes???
Post by: SpartanTravis on April 22, 2015, 05:22:09 am

So if I was going to upgrade the system to a JB5, what all would I need to change? ie. Brake booster, master cylinder, calipers, rotors, drums, lines?


Thanks,
Travis

Title: Re: JB5 or JD5 Brakes???
Post by: Irish_Alley on April 22, 2015, 05:45:14 am

let me ask you this, why? and what parts do you have now?

Title: Re: JB5 or JD5 Brakes???
Post by: SpartanTravis on April 22, 2015, 06:50:59 am

Well I already have the rotors, drums, pads, and shoes I got from a buddy for next to nothing. So if I all I need is a brake booster and a master cylinder then I'll fork out for them.


Thanks,
Travis

Title: Re: JB5 or JD5 Brakes???
Post by: Irish_Alley on April 22, 2015, 08:58:43 am

curious but are  they 6 lug or 8?

Title: Re: JB5 or JD5 Brakes???
Post by: Irish_Alley on April 22, 2015, 09:01:52 am

i dont think the brake upgrade would be worth it only for 1800 lb difference.

Title: Re: JB5 or JD5 Brakes???
Post by: SpartanTravis on April 22, 2015, 09:03:32 am

They're 6 lug.


Thanks,
Travis

Title: Re: JB5 or JD5 Brakes???
Post by: Irish_Alley on April 22, 2015, 09:14:41 am

will add this, i think the jb3, jb5 and jb6 use the same booster/cylinder.

to be clear youre talking about the new parts being 6 lug or the old or both?

Title: Re: JB5 or JD5 Brakes???
Post by: SpartanTravis on April 22, 2015, 10:05:00 am

All the new parts are 6 lug.


Thanks,
Travis

Title: Re: JB5 or JD5 Brakes???
Post by: Irish_Alley on April 22, 2015, 10:28:43 am

how do you know what type of brakes the new parts are? what the gvw of the new brakes? have you compared them to yours? (ie rotor size)

Title: Re: JB5 or JD5 Brakes???
Post by: SpartanTravis on April 22, 2015, 10:54:21 am

He still had all the receipts for everything. I just looked them up. Everything is for a JB5. The brakes are 1 1/4 inch.


Thanks,
Travis

Title: Re: JB5 or JD5 Brakes???
Post by: Irish_Alley on April 22, 2015, 11:38:41 am

front calipers are the same for jb 3 and 5. what year did the new parts come of?