14 bolt semi float factory locker

[AuroraGirl]

the 78 camper special sitting on my property... I found the RPO sticker! But, it listed all the things it had. Cruise control, bed light, rear locker, custom steer wheel, cheyanne trim, tilt wheel, AC, special chrome front bumper, etc. Locking rear sounded interesting to me. But how does that system work? Is it inferior or useless compared to modern options?

 

[75gmck25]

Camper Special should have a a high GVW (8200 or 8400) and a 14 bolt full float in a ‘78. It’s usually a 4.10 ratio. Rear hubs will stick out of the axle.

G80 Gov Lock has a mixed reputation. As wheel RPM goes up and there is about 200 RPM difference between the 2 rear wheels, a locking pawl extends out and locks left and right wheels together. It works fine if RPM comes up gradually, but sudden engagement, like from a pavement burnout, will break the mechanism. Hence the nickname. - Gov Bomb.

Gov lock is not designed for any type of racing. For that you want to use a GM Positraction setup, or similar.

Bruce

 

[Arkansas_V8]

G80- Gov bomb. Pin was pulled the day it was installed. It will explode, just a matter of time.

 

[AuroraGirl]

I forgot to take photo of hub.. but its 6 bolt. And not removeable like my k25

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[75gmck25]

Now I see the confusion.

Your door plate mentions camper loading, but it’s not a camper special truck. Camper Special chassis package is option Z81, and it’s only for 3/4 ton (or bigger) trucks. IIRC my data plate lists GVWR of 8400, axle loading, and then a max camper weight of 2650 lbs. The wide band around the back and side of the cab also has camper emblems that look like a teepee, and the logo under it says Camper Special 8400 GVW.

For those who want more info - A factory camper special also has special chassis tie towns in several places. One on each front fender under the windshield, and one on each back cab corner with a bracket that extended through the front of the box. The system seemed to tie the box and the cab together with the camper. The camper connected to the cab brackets with some type of shock absorber.

Bruce

 

[TubeTruck]

You have a "heavy half" it seems. @RoryH19 has the same rear. 6 lug semi float 14 bolt.

 

[calredneck]

Rally wheels 5 or 6 lug 1/2 ton

 

[RoryH19]

You have a "heavy half" it seems. @RoryH19 has the same rear. 6 lug semi float 14 bolt.

My heavy half is a "unique" rear end from a mid 90' GMT 400.
It is 6 lug, 14 bolt, 9.5 ring semi float.
Squares that are 14 bolt with 9.5 semi or 10.5 full float are 8 lugs.

How many bolts on your rear diff cover and how many lugs do you have?

Edit:
Just saw your pic, is that a 12 bolt rear diff?
If so, that is correct for a 70's 1/2 ton.

 

[AuroraGirl]

Im confused. The VIN indicates a 3/4 ton? But yall say heavy half? Wouldnt a heavy half be indicated as a 1/2 ton? What makes it a heavy half vs just 3/4? The differentials and springs? And ohhhhh okay I see, not a camper special, which is fine. But the thing seems to still be tricked out for dealer add ons, relatively.

 

[TubeTruck]

Im confused. The VIN indicates a 3/4 ton? But yall say heavy half? Wouldnt a heavy half be indicated as a 1/2 ton? What makes it a heavy half vs just 3/4? The differentials and springs? And ohhhhh okay I see, not a camper special, which is fine. But the thing seems to still be tricked out for dealer add ons, relatively.

The VIN you posted above, CKR148S114410, indicates a 1/2 ton. I was mistaken about the heavy 1/2 as Rory had pointed out. Those were only '88-'98 trucks. The rear is most likely a 10 or 12 bolt, but looks like a 12 bolt (I count 8 bolts that I can see, which is about 2/3 of the cover).

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[AuroraGirl]

Evidently I cannot count then, Lmao, okay. That is fine, Im not upset by that because Id really kill for a half ton square... I was thinking about how i have no need for two 3/4 ton trucks.. this changes everything.

Does a 4wd 1/2 ton with a long bed and a 400 seem... unusual? Maybe Im just thinking things.

 

[TubeTruck]

Click HERE to view the different trim levels and packages. For a Cheyenne with a tow package the 400 was not unusual.

 

[75gmck25]

I believe this high GVW half ton was called the Big 10. Catalytic converters started in ‘75, but this ‘78 had a GVW above 6000 lbs so it did not need catalytic converters. Ford also introduced the F150 in ‘75 as a higher GVW, non-converter version of the F100.

Later on (not sure of the year) they increased the GVW threshold for converters so they were required on all half tons.

I think the SBC 400 was a relatively unusual option, but I’m not sure.

Bruce

 

[scwaters]

Pardon my ignorance but what is a14 bolt semi float factory locker. I know it’s a differential I understand it has 14 bolts on the cover.

 

[75gmck25]

14 bolts is the number of cover bolts - just a shorthand way to identify the axle since lighter duty axles had 10 or 12 bolt covers.

14 bolt axles came in multiple versions.
- A 9 1/2” ring gear semi floating 14 bolt axle with a 6 bolt wheel pattern is a standard design where the axle has a c-clip holding it on the differential end. If that clip breaks or the axle itself breaks, the axle, outer hub and wheel may pull/fall out and leave one side of the truck on the ground.
- A 10 1/2” ring gear full floating 14 bolt axle with an 8 bolt wheel pattern has the outer hub bolted on the end of the axle tube and the axle just “floats” between the differential and the outer hub. If an axle breaks, the truck just stops moving, because the broken axle remains in the tube and the wheel stays on. You can visually verify a full float rear axle because the hub sticks out through the center of the wheel, much like the front of a 4WD truck axle.

Some of them had the G80 factory locker option. This is a simple centrifugal design that locks the left and right wheels together when wheel rpm is about 100-200 rpm difference. It can be damaged if wheel rpm goes up too quickly (stuck in the mud?) and it engages too suddenly.

Bruce