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Need to do rear brakes but confused by rear end

M

millsroger

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Bonanza, Or.
OK guys, RPO code is G80. Was told rear end is 14 bolt Dana 70 but that don't work. Per pics looking at the back of the 70 the tall point would be to the drivers side of center. Mine has tall part on passenger side of center--14 bolt pattern tho. Best I found was something about a "corporate" that looks like it has the same bolt pattern, but, the listing says up until mid 80's on 1 ton and nothing else about it, except 10.5 ring gear. Mine is an 8 lug and 9000 GVW so what is this rear end????

Am told that hubs have to come apart and axles out to get the drum off, anybody got a how to DIY? If not is the brake system shown in like Haynes or Chilton---or do I need a different book????

Need to know something to get seals, gaskets and shoes.:nonod:
 
A unique property of a GM corporate 14 bolt 10.5" full floater rear axle. I think this is what you have, right?

(makes it easy to ID without a picature)
 
OK, think I got it, pull the bolts and the pinion/bearing assy pulls out the front. Will look. So---is it just called the "corporate 14" or ????? Or do I just call it the 8 lug?
 
No need to remove pinion.. Just an ID method.

Yep GM corporate 14 bolt 10.5 inch ring gear floating axles.

Now, brakes. Usually two sizes, One, the JB8 RPO 13x3.5 outboard drum brakes like my SRW one ton.

Or the inboard (gotta pull axles to service brakes) 13x2.5 drum.

Outboard 13x3.5 brake drums just slide right off.. :)
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Must be the "inboard" type, is a plate with spacers back to drum, found a link, will post it later here, gotta go for a bit.
 
I looked in the Master RPO list; the JB8 is a 10k lb rated disc/drum brake system so prolly the 3.5" wide, only thing heavier is a couple of JH's in disc/disc. Mine is a JD7 which is 8400 lb rated disc/drum brake system, sub note "except F44 is 9000 lb" which mine is, (that's a heavy duty chassis code).
 
You just can't tell which style drums you have until you get the rear wheels off and see if the drums slide over or go behind the hub. it seems most 2500 trucks require hub removal though.
 
Did that, drums are behind a flange ring, according to pics and info from Pirate it is a Type A used on C/K and vans above a certain GVW. Type B is the version for Dually and C-C's plus 'A few others' he did not list.
 
My 93 C&C and 94 K3500 both have 3.5" #9000 rating on the 94. Sometimes i think the RPO Code is worthless lol.

Your Type A over certain GVWR probably pertains to the weight rating where the axle changes from a 9.5 Semi Floater up to a 10.5 full float
 
From the pics and chart on pirate the type a is SRW, type b is DRW. Apparrently, this is only his code for them. From what he says, the hub can be swapped in the housing, just use the right axlebrawler_hub3.jpg. Snipped a pic of the hubs A on left. Biggest differences seem to be width and axle lengths.
 
Still don't know which brake shoes I have, guess I will need to pull a drum to find out. That's where the RPO codes don't tell you anything except type and weight rating. Mine could be either one. Everything related to running gear seems to be for a 3500. It looks to me like GM used a 3500 8 lug SRW chassis and slapped a 2500 logo on it. Fine by me, insurance is cheaper.
 
Likely you will need the wheel seals National part number 2081. These go in the drum to seal the oil in the full floater bearings. The part description makes the part hard to find... Note that the proportioning valve is suspect on old trucks like these. Also the rear brakes need to be adjusted often as the auto adjusters don't do it well.

1500/2500/3500 all come in light and heavy duty versions. Then camper specials etc. The 2500 is a starting point, the the weight rating, then...

Make sure you get the expensive shoes that cost around $100. They are well worth is vs. anything cheaper. If you want to know why ask how hard I work mine...
 
Thanks War, BUT, brings a question, you said "in the drum", by that you mean the drum/hub assy. right? Looks to me like in the hub part. Now a "BIG" question, if I need drums, how do they come off the hub?

Yep, raybestos semi-metallic, only thing I buy, also lifetime warranty. Once installed, if I have trouble on the road only thing it costs me is labor.

OK, prop. valve--saw a couple of posts and some confusion. I know of the valve in the front-safety shut off pop over valve to F/R if pressure loss. Why would that be suspect?? Does this have the "load control vavle" in the rear that's linked to the body?? Or is it a L/R proportional control valve in the RWABS?? Load control I could find if there, but a separate L/R proportioning valve could be front near master cyl. or rear near diff. , can look like an oversized T, others are electronic solenoid valves. What does this have and can they be cleaned??
 
War,

You are right, light and heavy versions but it's not quite that simple. What I found is that a 1500 can go up to above a base 2500, and a 2500 can go up to above a base 3500, then a 3500 can go up to what would be a 4500. All I need to do is swap drums and hubs and mine would be the same 10k GVWR as a 3500 HD dually, not quite max for a 3500 but very close. Other thing that confuses the bleep outa things is stuff like a C-C with 5 lug fronts and 10 lug dual rear. My truck is a special order, #3 of 3, and I think there were enough similar orders that later on GM started to use the "HD" to identify these versions-but then so did Ford and Chrysler--became a marketing thing, now its a downright competition.
 
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