The 8600 calipers are a direct bolt on, and use a 370 series pad, rather than the 369 series pads of the 7200 calipers.
I've got a 1998 K1500 Suburban which was equipped with JB6 brakes.
I bought the 8600 calipers and 370-series pads and they are "bolt on", but in my case the
outboard pads rubbed ever-so-slighly against the hub of the rotor (others may or may not have this problem). I had to grind the outboard pads (not the inboard) to clearance them, which wasn't a difficult undertaking. See the attached image.
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I've heard of others who used the 7200 pads (369-series, e.g., RAYBESTOS EHT369H) with the 8600 calipers instead. Assuming these fit and function propertly on the 8600 caliper, they would provide more clearance for the hub of the rotor. I haven't tried this yet, however, and can't comment.
Part numbers I used, for the 8600 calipers and 370-series pads:
Caliper w/ 3.15" diameter piston RAYBESTOS FRC4414C
Caliper w/ 3.15" diameter piston RAYBESTOS FRC4413C
Pads for above calipers RAYBESTOS EHT370H
(Edit: As posted later in this thread, the K3500 DRW calipers w/ piston diameter 3.386" can also be used, e.g., see CENTRIC 14266021 et al.).
Finally, the argument has been made that the JB5/JB6 MC, which is a "Quick Take-Up" design meant to be used with corresponding JB5/JB6 "Quick Take-Up" calipers, should not be used with the 8600 calipers as they're not "Quick Take-Up" calipers (the "Quick Take-Up" feature was OE for JB5/JB6 GMT400s at least in later years GMT400s, see the attached .pdf for its explaination; I'm not certain if it was deployed in 1988). On account of the "Quick Take-Up" MC or for other reasons, many have "upgraded" to the 8600 MC or the NBS MC. Personally, I used the NBS MC from a 2001 1500 Silverado. Some adapters may be required, e.g., to mate the NBS MC to the brake lines, but otherwise the NBS MC bolts right in. Do your homework; the NBS MC swap is discussed in many places here on GMT400.
Part number:
NBS MC ACDelco 18M1159
I have the 11" drums in the rear and I installed the 1.1875" diameter JB8 cylinders in place of the 1" OE diameter cylinders. I did not change the drums / shoes as they were serviceable. This change IMHO works particularly well on the Suburban because it's a$$-heavy compared to an (unloaded) pickup, i.e., about 3020# in front and 3160# in the rear. These cylinders bolt right in, without issue.
Part number:
Cylinder ACDELCO 18E1362
I've also installed braided SS lines front and rear. Bear in mind that some of the aftermarket SS lines are better than others as noted by
@Schurkey in recent discussions. If I find a link to his post I'll pass it along. (Edit: see here
https://www.gmt400.com/threads/upgrade-front-brake-calipers.58795/post-1254517)
The part numbers I've given are what *I* used. Equivalent parts are available from other mfgrs.
IIRC, during the life of the GMT400 platform the some / all of the brake line fittings were changed from SAE to metric... perhaps around 1997. The information I've given you is relevant to my 1998 Suburban. Before you commit to installing new parts, make certain the fittings are appropriate. I've "been there" and I've suffered the consequences.
Finally, peruse this thread as it has a lot of discussion that's relevant to your vehicle:
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...
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