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73-87chevytrucks.com
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73-87 Chevy _ GMC Trucks
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Brakes, Frame, Steering & Suspension
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Brakes and Braking Systems
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Rear brake shoes
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Topic: Rear brake shoes (Read 2917 times)
Cheyenne1010
Newbie
Posts: 60
Newbie
Rear brake shoes
«
on:
June 10, 2018, 08:43:20 PM »
I got a 1973 chevy C10 and I'm doing the rear brake shoes
I notice the shoes are not exactly alike,one shoe has more brake material then the other one,why is that?
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Big Chip
Newbie
Posts: 94
Newbie
Re: Rear brake shoes
«
Reply #1 on:
June 11, 2018, 09:18:56 AM »
Are you saying it’s thicker or longer? The longer one goes toward the front I believe.
Sent from my iPhone using Tapatalk
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bd
Global Moderator
Senior Member
Posts: 6438
Re: Rear brake shoes
«
Reply #2 on:
June 11, 2018, 12:20:34 PM »
The 73-87(91) GM trucks use a duo-servo brake system. The primary (forward or leading) shoe on both sides typically has shorter friction lining than the secondary (rearward or trailing) shoe. Duo-servo brakes are self-energizing, meaning that as the shoes are forced outward against the drum by pressure applied via the wheel cylinders, the forward movement of the vehicle and rotation direction of the drum rotates the primary shoe toward the secondary shoe through the automatic star adjuster located at the bottom of the backing plate. Since the automatic star adjuster is not anchored to the backing plate the rotational force of the primary shoe forces the secondary shoe into the heavy anchor pin that is fixed in position at the top of the backing plate, amplifying the outward force of the secondary shoe against the drum. Because of the self-energizing effect of duo-servo brakes, the secondary shoe presses outward against the drum with greater force than the primary shoe. Hence, the secondary shoe has more friction material (the lining has greater surface area) than the primary shoe to help equalize the wear on the shoes.
When backing up, the same principle applies except the drum rotates in the opposite direction. When backing up, the primary shoe presses against the drum with greater force than the secondary shoe (the roles are reversed). However, since so little time is expended braking while backing up, accelerated wear of the primary shoe is not an important consideration.
So, the important point to remember is that the secondary shoe has longer friction lining than the primary shoe and mounts in the trailing or rearward position.
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Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)
Captain Swampy
Junior Member
Posts: 504
Wisconsin
Re: Rear brake shoes
«
Reply #3 on:
June 11, 2018, 03:47:46 PM »
Thanks for taking time to explain all of that.
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1987 350TBI 700R4 4X4 4.56 gears 33" BFG All Terrain
http://forum.73-87chevytrucks.com/smforum/index.php?topic=32209.0
Spool
Junior Member
Posts: 509
Re: Rear brake shoes
«
Reply #4 on:
April 05, 2021, 01:21:42 AM »
Extremely well described, BD. Thank you.
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JohnnyPopper
Senior Member
Posts: 2526
Old Goof
Re: Rear brake shoes
«
Reply #5 on:
April 08, 2021, 08:59:38 PM »
bd is the Man!
Pretty cleaver how they designed the star adjuster to self adjust the shoe clearance while backing up.
I have to remind myself to deliberately come to a full stop in reverse so they adjust.
Unless you say we don't need to...?
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1957 Apache 3100 235 Inline 6, 3 on the tree
1973 C-20, 3+3 454 4BBL TH400 Water Injection
1978 K-10, 350 4BBL TH350 NP203 M.M. Part time Kit/Hubs
1980 C-10 under construction
bd
Global Moderator
Senior Member
Posts: 6438
Re: Rear brake shoes
«
Reply #6 on:
April 08, 2021, 09:10:56 PM »
Coming to a full stop is unnecessary. It merely requires a moderate to aggressive depression of the brake pedal while backing, preferably in a straight line to keep the adjustments balanced side-to-side.
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Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)
JohnnyPopper
Senior Member
Posts: 2526
Old Goof
Re: Rear brake shoes
«
Reply #7 on:
April 08, 2021, 09:16:50 PM »
I thank you and my NECK thanks you
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1957 Apache 3100 235 Inline 6, 3 on the tree
1973 C-20, 3+3 454 4BBL TH400 Water Injection
1978 K-10, 350 4BBL TH350 NP203 M.M. Part time Kit/Hubs
1980 C-10 under construction
bd
Global Moderator
Senior Member
Posts: 6438
Re: Rear brake shoes
«
Reply #8 on:
April 08, 2021, 09:26:44 PM »
Which neck?
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Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)
JohnnyPopper
Senior Member
Posts: 2526
Old Goof
Re: Rear brake shoes
«
Reply #9 on:
April 08, 2021, 09:40:44 PM »
The one my head rests on...
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1957 Apache 3100 235 Inline 6, 3 on the tree
1973 C-20, 3+3 454 4BBL TH400 Water Injection
1978 K-10, 350 4BBL TH350 NP203 M.M. Part time Kit/Hubs
1980 C-10 under construction
bd
Global Moderator
Senior Member
Posts: 6438
Re: Rear brake shoes
«
Reply #10 on:
April 08, 2021, 11:34:56 PM »
Just checkin'.
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Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)
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73-87chevytrucks.com
»
73-87 Chevy _ GMC Trucks
»
Brakes, Frame, Steering & Suspension
»
Brakes and Braking Systems
»
Rear brake shoes