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Old 09-22-2013, 03:28 PM   #1
taylorhannum
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brake help fast

I Have a 1971 c20 pickup truck 2wd. It has a dana axle but I am not sure what size rear drums and shoes I need and I don't have to time take it all apart and look. I was hoping someone might be able to help me out on this. Thanks!
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Old 09-22-2013, 05:34 PM   #2
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Re: brake help fast

There are two sizes of rear shoes, depending on whether you have leaf or coil springs.
For coil you should have 11 5/32 X 2 3/4" Napa part # UP248R
For leaf you should have 12 X 2/12", Napa part # UP419R
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Old 09-22-2013, 08:10 PM   #3
taylorhannum
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Re: brake help fast

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Originally Posted by 425HP409 View Post
There are two sizes of rear shoes, depending on whether you have leaf or coil springs.
For coil you should have 11 5/32 X 2 3/4" Napa part # UP248R
For leaf you should have 12 X 2/12", Napa part # UP419R
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Ok thank you and would you happen to know what the drum size I need for those as well? I have leaf springs
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Old 09-22-2013, 08:24 PM   #4
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Re: brake help fast

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Originally Posted by taylorhannum View Post
Ok thank you and would you happen to know what the drum size I need for those as well? I have leaf springs
Are you sure you need drums without taking it apart?

I have a C20 with coil springs and my drums cleaned up with very little metal removal. It's not easy to find a shop that can do this. An automotive drum lathe won't do it and a shop that does big trucks will tell you the drum is too small for their equipment.

I found a shop in Houston that does equipment like forklifts. Both drums $130.
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Old 09-22-2013, 08:32 PM   #5
taylorhannum
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Re: brake help fast

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Are you sure you need drums without taking it apart?

I have a C20 with coil springs and my drums cleaned up with very little metal removal. It's not easy to find a shop that can do this. An automotive drum lathe won't do it and a shop that does big trucks will tell you the drum is too small for their equipment.

I found a shop in Houston that does equipment like forklifts. Both drums $130.
Im sure I will need the drums. The brakes have been bad for a long time but i just never drive it. I figured it would be good to get new ones anyway because I can get drums and shoes for for 150 total here
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Old 09-22-2013, 11:58 PM   #6
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Re: brake help fast

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Ok thank you and would you happen to know what the drum size I need for those as well? I have leaf springs
The drums are the same size as the shoes. I doubt that you will need drums, unless the shoes have been metal to metal for awhile, they will be able to be resurfaced. Most automotive shop's lathes will be able to resurface a 12" drum.
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64 Bel Air Wagon, 400 Small Block
57 Bel Air all original 283 w/Factory Air
77 GMC Sprint, 454/425HP
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90 ZR1 Corvette
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Old 09-23-2013, 09:50 AM   #7
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Re: brake help fast

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Most automotive shop's lathes will be able to resurface a 12" drum.
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That wasn't what I found. The problem was the hub. This is a C20.
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Old 09-23-2013, 06:46 PM   #8
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Re: brake help fast

Does anyone know where I can get a diagram or video online of how to remove the drum for this truck?
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Old 09-23-2013, 07:12 PM   #9
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Re: brake help fast

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Does anyone know where I can get a diagram or video online of how to remove the drum for this truck?
Your truck has what is called a Full Floating Axle type differential. The rear brakes are not usually something that a novice would want to tackle by themselves. That said:
1. remove the wheel and tire
2. remove the 8 bolts that hold the axle, remove the axle by pulling straight out
3. Disengage the tang of the nut lock from slot or flat of lock nut, then remove lock nut from housing tube using appropriate tool
4. If there is another nut, remove it at this time.
5. Pull hub and drum assembly from axle housing
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68 SWB, Dad bought new, now 396 & factory ac
64 Impala SS, 409 425HP, 4 speed AC
64 Bel Air Wagon, 400 Small Block
57 Bel Air all original 283 w/Factory Air
77 GMC Sprint, 454/425HP
67 Olds 442, all original
90 ZR1 Corvette
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Old 09-23-2013, 07:43 PM   #10
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Re: brake help fast

I have never done the rear brakes before so yes I am a beginner at that. I pulled the axle shaft out but I now I need to pull a huge nut off. I am not sure of the size but is looks to bee around 60mm, I will post a pic. I know there are a lot of other locking rings and what not after that ( I think around 6 or so rings to pull off but I'm not sure) and yes I should probably hire someone but I am more of a do it yourself and figure it out hand of person lol.
I just want to know the exact size of the nut that is on there before I buy a socket and pull it off. If anyone knows what size.
Oh and just to give some more info on the truck it is a 1971 c20 pickup fleetside 2wd 3/4 ton with 8 lug wheels and a 400 big block. Everything is original. Any help would be greatly appreciated.
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Old 09-23-2013, 07:48 PM   #11
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Re: brake help fast

here is where I am at

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Old 09-23-2013, 07:55 PM   #12
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Re: brake help fast

There are 2 flat head screws holding the drum to the hub, remove those, slide the drum off if they are not embedded into the drum from scoring.

the screws will be in between a couple of the studs in the same bolt circle, unless the have been removed and clocked on differently.

also, you shouldn't have to touch those nuts in the pic unless you have 90 wt. on the shoes.

Another thing, with the leaf spring assy. you have a dana 60 axle, and with the big block should have a 3.54 gear ratio and a power-loc diff
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Old 09-23-2013, 09:27 PM   #13
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Re: brake help fast

This might help with the job maybe not with your question..

http://67-72chevytrucks.com/vboard/s...d.php?t=200268
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Swamp Rat build thread :
http://67-72chevytrucks.com/vboard/s...d.php?t=595019

72 3/4T 4X4
4" BDS Lift
33" BFG's
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Old 09-23-2013, 09:30 PM   #14
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Re: brake help fast

Quote:
Originally Posted by kwmech View Post
There are 2 flat head screws holding the drum to the hub, remove those, slide the drum off if they are not embedded into the drum from scoring.

the screws will be in between a couple of the studs in the same bolt circle, unless the have been removed and clocked on differently.

also, you shouldn't have to touch those nuts in the pic unless you have 90 wt. on the shoes.

Another thing, with the leaf spring assy. you have a dana 60 axle, and with the big block should have a 3.54 gear ratio and a power-loc diff
Good information kwmech, I haven't done one of these recently and forgot about the drum slipping off of the hub.
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68 SWB, Dad bought new, now 396 & factory ac
64 Impala SS, 409 425HP, 4 speed AC
64 Bel Air Wagon, 400 Small Block
57 Bel Air all original 283 w/Factory Air
77 GMC Sprint, 454/425HP
67 Olds 442, all original
90 ZR1 Corvette
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Old 09-23-2013, 09:33 PM   #15
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Re: brake help fast

This might help with the job maybe not with your question..

http://67-72chevytrucks.com/vboard/s...d.php?t=200268
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Swamp Rat build thread :
http://67-72chevytrucks.com/vboard/s...d.php?t=595019

72 3/4T 4X4
4" BDS Lift
33" BFG's
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