Brake Question

skratch

skratch

Well Oiled
Jun 15, 2017
1,120
bernardo nm
First Name
john
Willys Model
  1. CJ
Willys Year:
  1. 1958
I'm replacing the left rear brake cylinder on my 58 CJ5. Noticed the brake shoes have one long pad, the other is
quite a bit shorter. Just curious why that is.
 
The short lining always goes toward the front. The wheel cylinder pushes the front shoe out, then it grabs the rotating drum and tries to turn with it. That pushes on the star wheel adjuster to push the bottom of the rear shoe into the drum. The the wheel cylinder pushes the top of the rear shoe into the drum. Both forces act on the rear shoe, (the longer lining) so they call it a "duo-servo" drum brake.

As a result, the rear shoe has a longer lining surface than the short shoe because it does 75 percent of the braking.
 
Last edited:
pav1 said:
The short lining always goes toward the front. The wheel cylinder pushes the front shoe out, then it grabs the rotating drum and tries to turn with it. That pushes on the star wheel adjuster to push the bottom of the rear shoe into the drum. The the wheel cylinder pushes the top of the rear shoe into the drum. Both forces act on the rear shoe, (the longer lining) so they call it a "duo-servo" drum brake.

As a result, the rear shoe has a longer lining surface than the short shoe because it does 75 percent of the braking.
Click to expand...

Thanks Jason !
 
Brake shoes with different lining lengths are made that way to equalize the wear... No sense putting a long lining on a brake
shoe that will out last the other... So, to equalize the wear... And save a penny here and there...

Now, somebody explain to me why truck air brakes with S cams don't use a long/short shoe setup........
 
Short shoe in front on self energizing brakes. My 53 pu does not have self energizing brakes and the long shoe goes in front! I'm guessing the CJ is the same. Been too long since I had my 64 CJ5!
 
Here's a picture from my 1948 pickup that I just completed a couple of days ago...



...showing the front left brake assembly. These are Lockheed style brakes and others might also want to know this about Lockheed style brakes. Hydraulic pressure expands the wheel cylinder cups, which push the shoes against the drum. The shoes are NOT self-energizing. The Lockheed system is a front/rear shoe design with the bottom pivot for each shoe anchored to the backing plate. This design requires more pedal pressure to stop than self-energizing brakes since they rely solely on hydraulic pressure. The front shoes (primary) do most of the stopping and normally use a longer friction band. The rear shoes (secondary) normally use a shorter friction band. That might help some of you who think the shoes were installed backward as they would be if these were a Bendix style. Long shoe goes toward the front. As I said this is for my '48 but I would guess it's the same for your '53.

I hope that helps and good luck with your truck.

Thomas
Click to expand...

This copied from the link Joe B provided along with my comment.


That looks close to mine but mine is on a 58 CJ5, except mine has the springs & pin where yours has the tabs,
and the upper spring goes in the round holes at each end. And wouldn't you know it I just finished mine, left rear,
and put the short shoe in front :confused: as per an earlier post on a different thread. My fault, didn't know what self
energizing brakes are. Well, back to the shop, at least I'm getting smarter,,,,,, the hard way .............. ;)






Reply

Report Edit
 
Joe B said:
Guys,
Please check this post out to determine whether your brakes are Lockheed or Bendix type, as the "long shoe position" will be leading or trailing depending on the system:
https://www.oldwillysforum.com/forum/index.php?threads/brake-shoe-install.8036/#post-817.

...and then look through the rest of that terrific thread!
Click to expand...
Crap keep forgetting about pre self energized brakes.

Sorry, but yes if the shoes are not connected, the larger one on the front.

Thanks Joe
 
John,
The pins and springs make me think "Bendix"...

Do they have star wheel adjusters bridging the bottom of the shoes?

The Lockheed brakes adjust using concentric cams, and the bottom of the shoes rest on a stationary pivot post.

On Lockheeds, you'll also see those adjusting cams at 3 and 9 o'clock in the image posted by Thomas/BB767.

(Swapping in Bendix for the Lockheeds is an extremely popular brake upgrade.)
 
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Joe B said:
John,
The pins and springs make me think "Bendix"...

Do they have star wheel adjusters bridging the bottom of the shoes?

The Lockheed brakes adjust using concentric cams, and the bottom of the shoes rest on a stationary pivot post.

On Lockheeds, you'll also see those adjusting cams at 3 and 9 o'clock in the image posted by Thomas/BB767.

(Swapping in Bendix for the Lockheeds is an extremely popular brake upgrade.)
Click to expand...

No star wheel adjuster, does have the cams at 3 & 9, bottom of shoes rest on a stationary post.
Top of shoes no notched bar between them but have the corresponding notch on each shoe, just the spring hooked into round holes. Does
have the coil springs w/ round keepers mid way on shoes. No
emergency brake provision, it's got the drum type on rear drive shaft. I'll try to post a pic before I pull apart.

Thanks
 
Sure sounds like Lockheed. The pin type shoe retainers are unusual...
 
Blindmelon said:
Brake shoes with different lining lengths are made that way to equalize the wear... No sense putting a long lining on a brake
shoe that will out last the other... So, to equalize the wear... And save a penny here and there...

Now, somebody explain to me why truck air brakes with S cams don't use a long/short shoe setup........
Click to expand...

I believe that because of the massive weight of big trucks they need all the sq. in. of brake shoe they can muster. Ad who is the dumb ass who came up with disc brakes on the rear of mid sized trucks? Or internal self adjusting wheel cylinders?
diggerG
 
Joe B said:
Sure sounds like Lockheed. The pin type shoe retainers are unusual...
Click to expand...

Maybe updated ? Anyway got the shoes switched, no problem, had practice ya know. :)
Sorry no pics, forgot I had the hub in the way, actually it makes replacing the springs
easier, use the rim of the hub as a fulcrum to stretch them.
Thanks to all for the help !

John
 
Blindmelon said:
Brake shoes with different lining lengths are made that way to equalize the wear... No sense putting a long lining on a brake
shoe that will out last the other... So, to equalize the wear... And save a penny here and there...

Now, somebody explain to me why truck air brakes with S cams don't use a long/short shoe setup........
Click to expand...
I do have a partial answer... Large trucks need all the holding power they can find when parked on hills with a load... The the braking/holding power on trucks with S cam brakes is equal, whether they are parked uphill or down hill..

Braking/holding power could be increased (on Willys with Lockheed brakes) when backing or parking uphill if the rear shoes were also long lining shoes..

Not that anyone cares....
 
skratch said:
This copied from the link Joe B provided along with my comment.


That looks close to mine but mine is on a 58 CJ5, except mine has the springs & pin where yours has the tabs,
and the upper spring goes in the round holes at each end. And wouldn't you know it I just finished mine, left rear,
and put the short shoe in front :confused: as per an earlier post on a different thread. My fault, didn't know what self
energizing brakes are. Well, back to the shop, at least I'm getting smarter,,,,,, the hard way .............. ;)






Reply

Report Edit
Click to expand...
i just got done replacing my drum rear brakes on my 66 nova.....i watched an 8 minute youtube video....i was out there for 2 and a half hours! on one wheel! but now i know how to do it and lord help me the brakes work:)
 
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