according to my hayes manual the main return spring goes on from the backside of the shoes (does that make sense or no difference?) and the primary shoe goes toward the front but how do i know which one is the primary...one is thicker and has more lining than the other so i might be making a wrong assumption that this is the primary

this is for the rear on my 89 f350

 

The shoe with the most lining area will be the rear shoe.

 

i know my hayes manual is a piece of crap, but r u 100%

 

The primary shoe has a shorter lining and goes on the front.

 

none of this makes sense, why would the primary have shorter lining and be thinner

 

The primary lining is engaged first which pushes the secondary lining.
The secondary lining does most of the braking.
If you notice forward braking is much better than reverse braking.

 

finally i got the answer i was looking for...any ideas on whether the main return spring should go on from the backside or put on the shoes and then the spring from the front

thanks

 

I did not know mechanical things worked that different north of the boarder. Seriously, the wheel cylinder activates the tops of both shoes at the same time. There is no mechanism for the one lining (or shoe) to push the other except for the rear emergency brake activation where the cable can only pull one shoe and needs a mechanical link to push the other shoe. But the larger (more circumfrance of the shoe covered) lining goes to the rear of the vehicle.

 

> Seriously, the wheel cylinder activates the tops of both shoes at the same time.
> There is no mechanism for the one lining (or shoe) to push the other except

Mitchell Automechanics
ISBN 0-13-586124-1

Page 591

Regarding Bendix dual-servo action brakes:

"While it may seem like there is a lot holding the shoes motionless, they are actually free to move. When the brakes are applied, the wheel cylinder forces the shoes against the rotating drum. The drum's rotation tires to rotate the shoes.

In the Bendix design, the front, or PRIMARY shoe presses against the adjuster. The adjuster transmits the motion to the rear, or secondary shoe. This forces the secondary shoe against the anchor pin above the wheel cylinder. Because the anchor pin stops the shoe from rotating, the secondary shoe tries to pivot around it. This forces the secondary shoe against the brake drum.

The forcing of the secondary shoe by the primary shoe is servo action.

As you can see in Figure 40-4, most of the braking is done by the secondary shoe. That is why it has more lining area then the primary shoe."


My personal note from observation, the reason the front pad is shorter (and thinner) is because only a small amount of the pad actually provides action once rotated. The front shoe hardly ever wears out and one thing that burns me are so called "mechanics" that measure the front shoe when justifying a brake job while the customer watches them measure.

On many cars from Japan, both shoes are the same size.

 

man i hate brake shoes...i think i may have a bad hardware kit or shoes because the hold down springs r real loose...it also came with two u shaped clips about the size of a dime that i do not know where they go

does anyone have a procedure for doing brake shoes? picture? anything of use?
this sucks

 

It works the same no matter which side of the border you are on.
The rotation of the drum pushes the primary shoe into the secondary.
Whereas in reverse the opposite is true.

 

after wasting half a day it looks like a bad hardware kit...the springs were too far bent inward...i will find out tomorrow if it is any better

any help suggestions would be appreciated

 

"according to my hayes manual the main return spring goes on from the backside of the shoes (does that make sense or no difference?) "

That makes no sense to me. Impossible to get on that way.

The 2 u-clips are for the parking brake. They hold the parking brake bracket to the shoe. One for each side.

 

Oh yeah, one other thing. The small spring that holds the shoes together at the bottom... one end goes in the shoe, the other end goes to the adjuster (Not the other shoe). The cable that hooks up at the top and curves around the shoe to the bottom also hooks up to the adjuster.

 

i have heavy duty brakes with a different setup...btw i dont think the u-clips get used in my app but still come in the hardware kit