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73-87 Chevy _ GMC Trucks => Brakes, Frame, Steering & Suspension => Brakes and Braking Systems => Topic started by: 81Cheyenne on June 30, 2009, 08:24:11 am

Title: Which Brake System?
Post by: 81Cheyenne on June 30, 2009, 08:24:11 am

I'm rebuilding a 1982 K-24 Camper special.  How do I tell which brake system I have (JB5,JD7,JD6..etc)?
I'm wanting to get rid of the Hydroboost and convert to a Vacuum booster and I need to know which parts to buy. And no, I don't have the code sticker in the glove box. (rats)
thanks.

Title: Re: Which Brake System?
Post by: frogman68 on June 30, 2009, 08:28:21 am

If its Hydroboost wouldnt it be Jb8?

Title: Re: Which Brake System?
Post by: 81Cheyenne on June 30, 2009, 08:36:23 am

Quote from: frogman68 on June 30, 2009, 08:28:21 am

If its Hydroboost wouldnt it be Jb8?

Dunno.  I guess that I need to know which system to buy parts for if I want to change over to a heavy duty vacuum type brake booster.

Title: Re: Which Brake System?
Post by: 81Cheyenne on June 30, 2009, 03:24:37 pm

So, anybody have an opinion on changing a hydroboost to a vacuum boost?

Title: Re: Which Brake System?
Post by: VileZambonie on June 30, 2009, 03:37:18 pm

Just go with the heavy duty brake system.

Title: Re: Which Brake System?
Post by: Captkaos on June 30, 2009, 05:02:45 pm

JB8 is the 1T brakes, I believe you would have JB7 on a camper special.

JB1 BRAKE, MANUAL, DISC/DRUM, 4300 LBS
JB3 BRAKE, POWER, DISC/DRUM, 4600 LBS
JB5 BRAKE, POWER, DISC/DRUM, 6400 LBS
JB6 BRAKE, POWER, DISC, DRUM 7200 LBS
JB7 BRAKE, POWER, DISC, DRUM 8400 L85
JB8 8RAKE, POWER, DISC, DRUM 10000 LBS

Personally I would keep the hydroboost.

Title: Re: Which Brake System?
Post by: 81Cheyenne on July 01, 2009, 06:59:55 am

Quote from: Captkaos on June 30, 2009, 05:02:45 pm

Personally I would keep the hydroboost.

Is hydroboost that much better than vacuum?  I'm going to have to replace the master cylinder anyway and was wanting to get rid of some of the lines. I'll also have to buy another power steering pump if I keep the hydroboost.

Title: Re: Which Brake System?
Post by: Captkaos on July 01, 2009, 04:01:12 pm

Better is a vague term.  I just wouldn't remove it just to have Vacuum.
AND on a 3/4T truck you would need the HD booster if you changed it.

Title: Re: Which Brake System?
Post by: BigHemi353 on July 12, 2009, 12:24:13 am

Quote from: Captkaos on June 30, 2009, 05:02:45 pm

JB1 BRAKE, MANUAL, DISC/DRUM, 4300 LBS
JB3 BRAKE, POWER, DISC/DRUM, 4600 LBS
JB5 BRAKE, POWER, DISC/DRUM, 6400 LBS
JB6 BRAKE, POWER, DISC, DRUM 7200 LBS
JB7 BRAKE, POWER, DISC, DRUM 8400 L85
JB8 8RAKE, POWER, DISC, DRUM 10000 LBS

I have an 86 3/4 4x4. the code for my power brakes in the glove box are 1J55. Would this be JB5? My truck has the 6001-7000gvw brake system.

Title: Re: Which Brake System?
Post by: 78 Chevyrado on July 12, 2009, 02:35:04 pm

I looked on my build sheet for my '78 C20.  It has the H.D. Vacuum Powered Brakes

It's listed like this on the build sheet:

  J55  H.D. Power Brakes
=JB7  Vac Power Brakes


On the RPO sticker:
 J55  H.D. Power Brakes

Title: Re: Which Brake System?
Post by: BigHemi353 on July 12, 2009, 02:41:16 pm

Thanks Chevyrado! You've saved me alot of hair pulling at Autozone! lol