JB5 Rear to JB6 Drums 6 Lug - Help with Models to pick

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Bearclaw

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My truck is a 96’ GMC Yukon, 5.7 vortec, K1500, 2 Door, lifted on 35x12.50 tires, with factory JB5 brakes, 6 lug 10 bolt rear.

I’m looking for help identifying what models to pick the backer plates, and drums from to go from the 10” leading/trailing JB5 rear drums to the 11.x JB6. I’ve read through old threads and searched but I’m asking for a straight shot set of model years and sizes of c/k1500/2500 trucks and suburbans to search for that I can pick these parts from..

I have a scan tool to do the ABS Bleed with, and before that will obviously be bleeding all the new lines. Won’t be diagnosin/chasing the ABS further until the lines and bleed are complete.

All help appreciated!

I’m restoring this truck after it’s sat for years, engine runs well, but I have an ABS light on and after looking at the lines and the overall condition I will be replacing all lines, hoses (with SS Braided hoses), and want to ditch the leading/trailing junk in the rear. At this time for budget easing I’m not entertaining rear disc, NBS MC, or a full rear axle swap just yet. I feel like the JB6 system will suit me, but am open to suggestions.

My goal is to have this truck in dependable condition as a daily driver for my son when he turns 16, 2 years from now.

In the short term I’d like to get it drivable and able to pass an inspection so we can run around town in it as we complete the resto.

Needs interior work, a/c work, and a list of other things which I’ll post about later as the resto progresses.
 
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HotrodZ06

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I was looking into it as well for my 96 k1500. I believe you would want to look at six lug suburbans, escalades, and possibly denalis or police tahoes for the 11x2.75 rear drums. Not 100% sure though.
 

Bearclaw

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I was looking into it as well for my 96 k1500. I believe you would want to look at six lug suburbans, escalades, and possibly denalis or police tahoes for the 11x2.75 rear drums. Not 100% sure though.
Yes sir, that’s exactly what I’m looking for. I’m learning and reading as much as I can absorb, hoping this thread will lead me to a cheat sheet of models/years with the 6 lug JB6 that I can seek out. I’m just having trouble with the different axles etc, as I see these 11.x rears were offered on many different models. Any starter list of models for me to seek that are guaranteed to have the 11.x rears would be a big leg up
 

Schurkey

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You're running 35's.. I'd just go ahead and get a whole 14 bolt 9.5" rear end and swap it in, before you grenade the 10 bolt.
You got there before I did.

If the truck has the weakass 10-bolt 8.5" axle, the only reasonable "brake swap" is to take the whole 9.5" axle from a "light duty" 6-lug K2500. Brake AND axle upgrade in one.

Choose the core axle wisely, and you'd get a gear upgrade as well--but then you have to change the gearing at the front, too.

When it was me, I kept the gear ratio, but got G80 Gov-Lock which isn't particularly troublesome in the 9.5" version like it is in the 8.5.
 

HotrodZ06

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You're running 35's.. I'd just go ahead and get a whole 14 bolt 9.5" rear end and swap it in, before you grenade the 10 bolt. What gears you have?

Richard
I believe all the 9.5 14 bolt six lug were 11 inch drums. But narrows the search to either a F44 1500 or 7200 gvw 2500.
 

1998_K1500_Sub

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a cheat sheet of models/years with the 6 lug JB6 that I can seek out.

The 11” drums and 8.5” rear seem to be common on the 5.7L 1500 Suburban.

The 5.7L 1500 Tahoes that I’ve seen in the yards (was there ever a 2500 Tahoe?) were given the 10” drums and 8.5” rear.

I’m not sure about the diesels or the 2500 versions.

There are both 5-bolt and 6-bolt 11” drums on the GMT400s.

The 8.5” ain’t the best as has been mentioned. I rarely trailer anything heavy, yet I’ve spun the carrier in the bearings once already.

I would like a 9.5” someday.

I’ve 3.73 gears on 275/65-18 (IIRC) tires.

I might guess one would want 4.10 or 4.56 gears when using a tall tire.
 

Bearclaw

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You're running 35's.. I'd just go ahead and get a whole 14 bolt 9.5" rear end and swap it in, before you grenade the 10 bolt. What gears you have?

Richard
Thanks for the replies, looks like I'll be repairing the current brakes for a temporary fix, then moving to a new 9.5" axle for a permanent solution. Truck has 3.73 gears currently according to RPO (GT4 G80). And I agree, 4.10 or 4.56 gears would be a big improvement. Looks like the 4.10 gears are RPO GT84 GT5/GT8. Any particular RPO codes I should seek out for those? New front gears will be happening as well obviously. I definitely want to get this truck right, and driving well!
 

Bearclaw

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According the the charts I'm finding, 4.56 gears are probably best for this setup. Are they common in the 9.5" 14 bolt or should I prepare to re-gear one?
 
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