I have the NBS MC.
I have the NBS MC as well and I'm very pleased with the brakes. However, knowing what I know now, I would recommend the JB7+ MC instead, but I'm not about to replace my NBS MC and I don't suggest you replace yours either. The NBS MC has a notably larger bore (1.34" / 34mm) than the GMT400s (1.25" or 1.125", depending on vehicle and boost method), so arguably the NBS MC takes more pedal pressure to yield the same braking ability, all other things being equal. However, my use of oversized (for my vehicle) caliper pistons (3.15" vs. 3") and oversized brake drum cylinders (1.1875" vs. 1") helps re-establish more-or-less the master/slave cylinder ratio which the vehicle had originally.
That said, for the front then it sound like I should get the 80 or 83mm calipers off a 3500 chassis as noted above. Is it the same prodcedure then? Swap the correct hub/rotor/caliper from a 3500?
The larger-piston calipers come in two flavors, 86mm/3.385" piston calipers and 80mm/3.15". My OE were 76mm/3". I replaced them with the 80mm calipers. I wasn't aware at the time of the 86mm calipers. See...
Suburban axle swap
is he maintaining rabs functionality? Or... whatever a suburban has? That could get spicy 4 wheel ABS is standard in the 95+ and it wont be a problem. There are no ABS sensors on any GMT400 rear axle. As long as the gear ratio is the same, the ABS wont know the difference. My '00 Yukon...
www.gmt400.com
and
Upgrade Front Brake Calipers
How much of an upgrade is it using larger 12.50 caliper with the smaller 11.86 pads? Isn’t the pad to rotor surface the same? Is it just that much better a caliper? Not knocking any of this ^^^, just curious. Convince me, I may be interested.
www.gmt400.com
Regarding pads, some very modest tweaking is required. The JB7 pads are physically larger and (in most cases) rub against the 11" rotor's hat. See the posts in this thread:
Upgrade Front Brake Calipers
Hi I am new to the forum. I Looking to upgrade my brakes. I have a 88 GMC K2500 with 6 lug wheels..(7200lbs). I have front calipers with the 2.94 diameter piston. Has anyone upgraded to the 3.15 calipers from the 8 lug (8600lbs) calipers. Is this a direct bolt on caliper. The only difference...
www.gmt400.com
In the same thread also note the comments from others (such as @Supercharged111)
who have used the smaller JB5/JB6 pads in the larger calipers; they claim they'll fit with a little bit of tweaking.
Do take note: Somewhere in the GMT400 production run GM changed from SAE fittings to metric. I believe it was around 1997/1998 b/c one of my Suburban's front fittings was metric and the other was SAE (I was scratching my head about THAT one for a LONG time when I was trying to install replacement SS brake hoses). This shouldn't matter to you unless you're going to replace the hoses b/c, obviously, you'll want to get hoses that have fittings that mate with existing brake lines.
You may need to bleed your system, and with ABS that can involve other steps. @Schurkey may comment; I know he has posted on this topic. I have never bled the ABS on my 1998 and my pedal's as firm as any IMHO, perhaps I've just been lucky; I've bled the rest of the system, yes, but not the ABS using the service manual's procedure.
Here's another thread you might peruse over dinner:
Need help with brakes plz!
Hi, I couldnt find a brake section. I have a newly aquired 1996 C1500 i think it's called. 4.3l, 8 ft bed. I bought it for a teenage stepson and really need to figure out the brakes. The owner before me put in new brake hoses, new master cylinder, new rear drums, new rotors and pads up front...
www.gmt400.com
(edit) I've said here and in other posts that there are 86mm piston calipers for the GMT400, and occasionally I've included part numbers. I've not personally seen the 86mm calipers, I've simply quoted the specs. I do have a PICTURE, which I believe was posted on GMT400, of a caliper with a piston that's ~3.25" / 83mm diameter. So... be advised. I've attached the picture below. (edit) This observation is explained in a later post, read on...
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