Caprice (9c1) rear disk brakes....

[clos69]

I bought a rearend of a 1995 caprice a couple of months ago and was wondering if anyone has one installed on their truck. The reason I bought it was for the 5lug conversion and rear disks and i believe it has positrac...not sure. Here are some pics

[406 Q-ship]

Yes it will be a posi (disc brake rear axles on cars are posi). The bolt pattern will be correct for 5 on 5 conversion, the B-body GM cars after 1970 are the same lug pattern as the 71 and up 5 lug trucks. The width will more likely be the biggest issue if you want to install the whole rear axle. A 9C1 Caprice is also more likely to have 3.42 gears, 3.08 were in police cars too.

[Longhorn Man]

that rear is probably worth more to an SS Impalla guy than disks are worth on the back of an empty pickup

[Skip Greaney]

I do not know much...but this one I know! 9C1 was Police package option, and if it came out of a Caprice it is about 3/4 of an inch NARROWER than an Impala SS 1996 back! Trust me they are different! Most will not notice that small a difference but it is there!

[clos69]

Thx for the replies guys...can someone tell me what an early 67-70 and 71-71 stock rearends measure?? I think this one measure 62in but i need to double check.
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[WIDESIDE72]

I have a wrecked 94 Caprice 9C1 that I bought from my brother for the recently rebuilt LT1/ 4L60E. I am using the engine/ tran in my 55 1st series on an S10 chassis. I haven't decided if I want to use the rear axle in my 72 swb step, or sell it.

[maynardtruckin]

not sure of the exact measurement numbers but 63-69 are about 1 inch narrower than the 70-72's !

[gysgtc]

My 67 LWB is 57" from where square plates mount to axle tubes.
I---o---I

^
THIS MEASUREMENT

[clos69]

Originally Posted by gysgtc

My 67 LWB is 57" from where square plates mount to axle tubes.
I---o---I

^
THIS MEASUREMENT

So you figure +2.5in on each side of the rotor adds up to 62in mounting plate to mounting plate...am i measuring this correct??

[maynardtruckin]

Just measured my axle out of a 69 c10 and it was 54 inches backing plate to backing plate and the 70 and up axles are wider by like an inch or two.

[clos69]

Ok..I measured the Caprice rearend and its 62in from mounting flange to mounting flange...i really wanted to use the entire axle but is the 62in width too big??

[Rawkus]

i just measured my '72 and its 63 3/4 wms to wms

[clos69]

Thx Rawkus...is urs the stock rearend from ur 72??
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[mustardjimmy71]

the 9c1 has 12" front disc. whats what size are yours. you will get better braking by going an inch bigger on the front disc than going from a drum to a disc on the back. when u hit brakes the weight goes forward and the front brakes do all the work. An out of ballance proportioning will lock up the rear drums with ease. The rear pads on my f150 are tiny. Ive also noticed rear discs make your wheels dirtier with brake dust

on the plus side rear discs look waaaaay better when visible. if your running a bigger open rim go with the discs for sure.

The 9c1 is a good rear end. I was going to put one in my 79 caprice but now that i know better im just putting in the swaybars from one. 9c1 has the bigger ten bolt 28 spline, 8.5" ring gear not a 7.5 like alot of the 80s vehicles and s10s.

Look into a f150 rear end. Mine has 355 gears, 34 spline axels and 9.75" ring and the disc brakes are engineered for a truck

[no moa]

9c1 rear ends are not all posi, they are all 3:08 gears. All the impala ss 94-96 were posi 3:08. The 9c1 is narrower. And yes if you don't use it, go over to impalassforums.com .
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[406 Q-ship]

Originally Posted by no moa

9c1 rear ends are not all posi, they are all 3:08 gears. All the impala ss 94-96 were posi 3:08. The 9c1 is narrower. And yes if you don't use it, go over to impalassforums.com I sold a couple over there.
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I have worked on 9C1 cars and can tell you that all disc brake rear axle from GM are Posi. Yes there are 3.42 in some 9C1 police cars (at least the later cop cars with disc brakes and LT1). It is the Impala SS that is only 3.08 ratio. I find it hard to believe that GM would make a special narrow axle for Police cars but I have not measured one so I cannot say for sure on that, stranger things GM has done.

[no moa]

Originally Posted by 406 Q-ship

I have worked on 9C1 cars and can tell you that all disc brake rear axle from GM are Posi. Yes there are 3.42 in some 9C1 police cars (at least the later cop cars with disc brakes and LT1). It is the Impala SS that is only 3.08 ratio. I find it hard to believe that GM would make a special narrow axle for Police cars but I have not measured one so I cannot say for sure on that, stranger things GM has done.

Nope.

I can tell you for a fact. that i have 4 9c1 police cars, 94-96 with the SPID code of GU4 ONLY 308 ratio. No G80.

The SPECIAL narrow axle, was used for TIRE CHAINS. The Civilian rears, and the SS rears are wider, the 9C1 police package cars, in the northern areas, used chains, the chains with the wider rear would desimate the rear fender wells.

I can also tell you that NO GM LT1 powered 9C1 cars came from the factory with a 342 GU6 rear axle. Infact i have never seen a B-Body with a 342 factrory GU6.

Camaro and firebird yes. B-Body no.

The cars that came with the 4.3 L99 v8 came with a GU5. 323. I have one with a posi G80. And i have one factory SPID NO POSI.

If you would like to verify this please go to:

www.impalassforum.com or any 9c1 site.

I have at least a dozen 94-96 9c1 police cars. It is my hobby. I have rebuild 3 of them from junk, and i have had 5 impala ss cars.

If you would like me to start Posting SPID tags, Compnine info, and such i would be MORE than happy to help you out.

2.14 G72 2.93 GU3
2.29 GH2 3.08 GU4
2.41 GU1 3.23 GU5
2.56 GM8 3.42 GU6
2.73 GU2 3.73 GT4

Positraction G80

[clos69]

Thanks for the info guys...Im going to convert to disk up front also with the stock 73+ 5x5 1.25in rotor which I believe is 11in diameter. Im going to try to use the 9c1 in my truck and see how it goes.

[mustardjimmy71]

my 2000 f150 is also 5x5 bolt pattern

[clos69]

Originally Posted by mustardjimmy71

my 2000 f150 is also 5x5 bolt pattern

You might want to double check.....according to this site ...they are 5x5.5 or 5x139.7mm

[mustardjimmy71]

ahhh poop i were both wrong http://www.rimhelp.com/searchrecords...sort_type=desc

the f150 9.75" is a good light truck diff and if its the right width would be worth getting drilled to 5x5.

[no moa]

I'll say this, I'll put those 9c1 rear ends up against a truck rear anyday. We beat our 9c1s pretty hard, and I've only had one let go, and it was a carrier bearing. They are tough rears
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[no moa]

Little more info.

Chevy
91-92 sedan
1566mm - narrow (all)

93-96 sedan
1566mm - narrow (9C1 - disc & drum & some other drum applications)
1598mm - wide (Impala SS - disc & B4U - drum)

Buick 91-96 & Fleetwood 93-96 sedans
1566mm - narrow (all)
NOTE: Fleetwood housing is unique to the application - 4-channel ABS provisions

91-96 wagon, all
1642.5mm

All 93-96 7.625" (ring gear) housings are 1598mm wide (Chevy sedan only)

Sedan housings, in both widths, have the same lower control arm bracket location/spread distance, and will fit any other sedan frame. Wagons have a wider spread distance (approx. 2") between lower control arm brackets on housing, and corresponding wider frame lower control arm mounts.

8.5" axle shaft information - sedans only

[no moa]

Stock '94-96 Caprice and Roadmaster sedans and wagons came with 2.56 gears as a base and 2.93 gears were an option.

Stock '94-96 Caprice 9C1s and Impala SS's came with 3.08.

Limited slip differential option (code G80 on the Service Parts ID sticker (SPID)) is an Auburn oem-style differential that is non-rebuildable. Aftermarket Auburn differentials are rebuildable by Auburn through an exchange program. The differential is an 8.5" style with 30-spline axles

[no moa]

Parts listed are applicable to 94-96 B-body sedans, some may be applicable to 91-93 models.

Note: information posted is as found on manufacturer/supplier websites. There ARE errors--some listings show NARROW housing axles as fitting Impala SS, which is incorrect--as relates to PRODUCTION configuration.

GM PART # 26038684
GM LIST: $328.83
DEALER COST: $194.93
DESCRIPTION: SHAFT,R/A - Caprice 9C1 w/rear disc (8.5/30 narrow)

GM PART # 26018080
GM LIST: $249.19
DEALER COST: $147.72
DESCRIPTION: SHAFT,R/A - Caprice sedan, Buick Roadmaster sedan w/rear drum (8.5/30 narrow)

GM PART # 26043164
GM LIST: $353.88
DEALER COST: $209.78
DESCRIPTION: SHAFT,R/A - Impala SS - rear disc (8.5/30 wide)NOTE can be used in place of 26033203 on B4U Caprice applications (26033203 discontinued)

Above info from GM PARTS DIRECT