Author Topic: Help identifying 12 bolt rear end!  (Read 2600 times)

Offline amplifiedsilence

  • Newbie
  • Posts: 23
  • Newbie
Help identifying 12 bolt rear end!
« on: May 23, 2016, 04:45:44 PM »
Alright, so I made some discoveries this past weekend about my 86 c10. Apearently the rear end is not the original one and perhaps is an earlier year.

Here is the info I have:

It is a 12 bolt gm rear, 5 lug and out of a truck



here a the markings I found-

Driver side, rear diff, Looks like G183


Passenger-side front tube, looks like KA W204 1



I hope someone can help me out! I mainly want to know what year it is, that way getting parts like brakes won't be such a pain!

1986 C10 - 79 350

Offline Fulltimechevy89

  • Newbie
  • Posts: 36
  • Newbie
Re: Help identifying 12 bolt rear end!
« Reply #1 on: May 23, 2016, 05:38:16 PM »
Just had some rear brake work done on my 77 K10 Chevy 350, and it turns out most of the parts on the drum brakes and the rear axle is off a 72 Chevy truck. Just goes to show you how much you really don't know about these trucks.

Offline Blazin

  • Blazin new trails!
  • Global Moderator
  • Senior Member
  • *****
  • Posts: 6130
Re: Help identifying 12 bolt rear end!
« Reply #2 on: May 24, 2016, 08:46:21 PM »
Pull the drum off, and messure the brakes will be your best bet.
Some people are like Slinkies. Not really good for anything, but they still bring a smile to your face when you push them down a flight of stairs

Offline amplifiedsilence

  • Newbie
  • Posts: 23
  • Newbie
Re: Help identifying 12 bolt rear end!
« Reply #3 on: May 24, 2016, 10:13:53 PM »
Thanks guys, I figured that it would come down to measuring the shoes and drums. I believe a ballpark range could be mid 70s to early 80s.

I have looked at the diagrams on   and noticed the wheel cylinders are the same for 73- 87 and similar to what I see on my truck.

1986 C10 - 79 350

Offline VileZambonie

  • Global Moderator
  • Senior Member
  • *****
  • Posts: 18519
Re: Help identifying 12 bolt rear end!
« Reply #4 on: May 25, 2016, 01:14:19 PM »
Measuring shoes and drums does not dictate what the rear end is. The brakes are based on how the vehicle was outfitted. What exactly are you trying to find out? If it's a 12 bolt truck 5 lug rear end they were the same up to 81
,                           ___ 
                         /  _ _ _\_
              ⌠ŻŻŻŻŻ'   [☼===☼]
              `()_);-;()_)--o--)_)

74 GMC, 75 K5, 84 GMC, 85 K20, 86 k20, 79 K10

Offline amplifiedsilence

  • Newbie
  • Posts: 23
  • Newbie
Re: Help identifying 12 bolt rear end!
« Reply #5 on: May 25, 2016, 08:31:55 PM »
I wanted to know what year it was to make finding parts such as brakes and seals easier to order. I realize now that the hardware is similar between 12 bolt truck rear ends from 74-81.

I did want to figure out what year it was though, since its not what came on 1986 trucks, for curiosity sake.

was able to replace the yoke this afternoon so I now know for sure that some of the 12 bolt rear parts are interchangeable.

1986 C10 - 79 350

Offline amplifiedsilence

  • Newbie
  • Posts: 23
  • Newbie
Re: Help identifying 12 bolt rear end!
« Reply #6 on: May 29, 2016, 10:26:10 AM »
I got both rear brakes and wheel cylinders replaced yesterday, used a 1975 rear end for reference when getting parts, I just measured the shoe width, all parts relate to that measurement, thanks!
1986 C10 - 79 350