9.5 14 bolt swap questions, beat to death I know............

[Knuckle Dragger]

I'm completely mystified as to why you'd want to keep the horrible half-ton rear drum brakes. Nobody ever uses the park brake, therefore they never adjust; therefore the brake pedal is always low. Seems like the front brakes wear fast because the rears aren't doing their job--too small, and maybe too far out of adjustment.

For me, getting 3/4-ton Duo-Servo rear brakes with the 9.5 axle was a third of my reason for swapping out the 1/2-ton 8.5" axle. (1/3 old axle was just plain worn-out, 1/3 changing from open diff to Gov-Loc)


Backing plates bolt-on.

You have a lot of assumptions projected on my truck based on your experience with your truck.

My truck isn't for racing, hauling, towing etc. It's something for me to tinker with, drive around at my leisure, maybe tow a small trailer or haul a new dresser once in a while. I've built a couple of Corvairs, couple 2nd gen Camaro's and few other toys over the years. The truck is my final toy since both my boys would really like to inherit this one. I don't need a 9.5 rear end. The 8.5 would do just fine. I rebuilt it a few years back and frankly I just don't like the 4:11 gears. I have some health issues that make rebuilding the rear end a slow process and I don't want to take the truck out of commission while I do it. I'll rebuild another unit as time and money permits and swap it in when it's done. It's more interesting to upgrade to the 9.5 since I'm going with a different housing anyway, I've never built a GM 9.5. With the NBS master and hydro-boost I have zero brake issues, pedal engagement is high, it stops balanced, I like the feel of what I've got and it's all been replaced recently so I don't need to change anything there.

If we all did it the same way it would be pretty boring.

 

[Knuckle Dragger]

Actually looking at Rock Auto if you look up the 92/93 years they list both rear drum size AC Delco part numbers l, so 454ss those years probably had the jb6 option, GM just did not manufacture many of those trucks.

I came to the conclusion I didn't trust a lot of the parts listings for the 454ss stuff. Even using a 454ss vin to identify the vehicle the various catalogs were pulling up 8.5 stuff. I agree both brake packages were likely available.


If anyone cares the GM number for the 5 lug axle was 26016185. I was never able to find any replacements that are still available.

 

[CW73]

I've heard some people say this and others say that the spring perches are slightly different, nice to hear from someone with first hand experience that the only difference is the sway bar mounts. Thanks for that.

I second that.. I've swapped SUV rears to trucks and vice versa.

 

[CW73]

I came to the conclusion I didn't trust a lot of the parts listings for the 454ss stuff. Even using a 454ss vin to identify the vehicle the various catalogs were pulling up 8.5 stuff. I agree both brake packages were likely available.


If anyone cares the GM number for the 5 lug axle was 26016185. I was never able to find any replacements that are still available.

 

[CW73]

The 454SS 9.5 axle is different from 9.5 6 or 8 lug housings. It had 8.5 C1500 drums.. the backing plates mounts are in different locations. Not sure if 8.5 5 lug backing plates would bolt up to a 9.5 6 lug but the drums wouldn't reach the shoes anyway.

 

[df2x4]

The 454SS 9.5 axle is different from 9.5 6 or 8 lug housings. It had 8.5 C1500 drums.. the backing plates mounts are in different locations. Not sure if 8.5 5 lug backing plates would bolt up to a 9.5 6 lug but the drums wouldn't reach the shoes anyway.

I'm curious if you can elaborate on this a little, this is the first I've heard about it. Are the backing plate mounts farther in on the 454SS axles and 8.5" 10 bolts than they are on the 9.5" six lug semi-floaters? Is this a problem that could be remedied with a spacer?

@Knuckle Dragger Did you ever figure anything else out on this?

 

[Supercharged111]

If the SS rear uses the wimpy little 10" drums, then the flanges would sit farther outboard than the 6 or 8 lug versions. I do know the tubes are a different length on 6 lug vs 8 lug, so this does not come as a surprise to me.

 

[df2x4]

I do know the tubes are a different length on 6 lug vs 8 lug, so this does not come as a surprise to me.

That makes me wonder if maybe the difference that CW73 mentioned could be exclusive to the 8 lug 9.5" 14 bolts.

@CW73 Is that a possibility or have you seen both 6 and 8 lug 9.5"s in person to verify?

 

[Supercharged111]

The difference on axle tube lengths lies in the drum depth which seems to be somehow based on drum diameter.

 

[df2x4]

The difference on axle tube lengths lies in the drum depth which seems to be somehow based on drum diameter.

I noticed that the drums for the 14 bolts look deeper than the ones for the 10 bolts on RockAuto.

I also found these flange dimension images on the Little Shop Mfg. website. Here's what they have in the listing for their 10" drum rear disc conversion kit which they state works with 5 lug light duty rear ends and 454SS trucks:

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And here's what they have in the 11" drum 5 lug rear disc conversion kit.

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The 11" drum to disc kit listing says it fits pickups and SUVs with "heavy duty 5 lug rear ends." I'm thinking maybe that's the flange you'd find on the non-454SS/Sport 9.5" 14 bolts.