Rear Brake Shoe Wear

7_Zero

7_Zero

Senior Member
The bottom shoe on the rear brake is wearing twice as fast as the top shoe. It is the same on both the driver and passenger side, is this typical? Is the bottom shoe the primary shoe? Or is this a sign there is something wrong with the rear brake cam that is preventing it from properly floating? The cam seems to slide when I push on it, so it isn't frozen up. I'd appreciate any suggestions on what to look for.

Thanks!
 
Did you center the shoes?

Did you take into account the wear that is sometimes at the bottom of the axle bearing race? I have seen fairly pronounced wear on some axles. I am not sure how that would affect the shoes as I would not use them.
 
The bottom shoe is the secondary shoe, thus it gets the most pressure and wear. The pressure from the top shoe pushes against the sliding pin, which pushes against the bottom shoe. The bottom shoe is stopped by the stationary adjusting wedge, so it becomes the secondary shoe.


Bearing wear as Kevin mentioned, might also cause added wear to the lower shoe.
 
7_Zero said:
The bottom shoe on the rear brake is wearing twice as fast as the top shoe. It is the same on both the driver and passenger side, is this typical? Is the bottom shoe the primary shoe? Or is this a sign there is something wrong with the rear brake cam that is preventing it from properly floating? The cam seems to slide when I push on it, so it isn't frozen up. I'd appreciate any suggestions on what to look for.

Thanks!
Click to expand...
Are your rear hubs Ford or After Market?
 
The rear hub bearings are different than the tapered front hub beareings. The long straight rear hub bearings ride on the outer bearing races that are part of the rear axle housings . The rear bearing races wear on the bottom .The rear hub races are part of the rear hubs and Ford recomended replacing the rear hubs if they were worn as much as .005 . I doubt that rear hubs are usually replaced unless they have more obvious problems . Bearing race wear in the hubs and axle housing races adds up and can cause the weight of the car to ride on the lower rear brake shoes. I always adjust the rear brakes with the rear wheels - tires on the shop floor . the car can be gently pushed forward and backwards while adjusting the rear brakes so as to feel the drag . If the rear brakes are adjusted with the car on stands there will usually be heavy drag when the rear wheels meet the floor.
 
Then live with the drag or have the bearing problems addressed. It won't necessarily be cheap . Just trying to give an easy inexpensive fix . Its not my problem !!!
 
Purdy Swoft said:
The rear hub bearings are different than the tapered front hub beareings. The long straight rear hub bearings ride on the outer bearing races that are part of the rear axle housings . The rear bearing races wear on the bottom .The rear hub races are part of the rear hubs and Ford recomended replacing the rear hubs if they were worn as much as .005 . I doubt that rear hubs are usually replaced unless they have more obvious problems . Bearing race wear in the hubs and axle housing races adds up and can cause the weight of the car to ride on the lower rear brake shoes. I always adjust the rear brakes with the rear wheels - tires on the shop floor . the car can be gently pushed forward and backwards while adjusting the rear brakes so as to feel the drag . If the rear brakes are adjusted with the car on stands there will usually be heavy drag when the rear wheels meet the floor.
Click to expand...



I have seen the problems of dragging brakes and adjustment problems caused by worn parts that Purdy speaks of above.

This is a true story...
 
Thank you all for your responses! I would have been so focused on the brakes themselves that I would have never figured it to be worn races.

Kevin, I do not know if the shoes were centered or not, we have not done much to the rear brakes aside from a slight adjustment or two since we bought the car. The individual shoes seem to be wearing evenly front to back, but the two shoes are wearing unequal to each other.

The bearing race on the axle looks okay, as in there does not appear to be any flat spots. Granted there is still probably the wear you speak of.

Growley, I am guessing that the hubs are original, or at least they don't look new. :-) One of them is the earlier style with an odd sized neck.

Purdy, the brakes are still a dark art to me, I am continually learning how to work with them. When adjusting the rear wheels with the car on the ground, would you disconnect the front brakes, adjust the rear then reconnect and adjust the front?

Thanks!
 
I would disconnect the brake rods front and back on the clevis end of the brake rods. I would first adjust the rear brakes with the wheels on the floor with very slight if any drag .. I would check and adjust the front brakes with the front axle on stands as usual and check that the front brake levers slant forward about 15 degrees . If the front levers don't have a foward lean , I would let off the adjustment , remove the front drums and either add brake shims to take up wear at the front lower brake wedges or replace or build up the brake activating pins to proper length . Then replace the drums and readjust the front brakes . While the brake rods are disconnected I would disconnect the brake pedal rod at the brake pedal and prop the pedal up at the top of its travel . The pedal rod has a round plunger that meets the brake light switch on the 30-31 models at the inside rear of the center cross member . There needs to be about a 1/16 gap between the plunger on the pedal rod and the inside rear of the center crossmember .Adjust the pedal rod clevis so that the brake rod clevis pin will just enter the brake pedal arm . Adjust the clevis on each service brake rod so that the clevis pin will just enter the clevis and brake levers with all slack adjusted out . This will have the brakes set up in such a way that when the pedal is depressed it will be ready to activate the brakes. Similar instructions can be found in the service bulletins . If you can follow these instructions , you will be surprised at how well that the brakes will work. Needless to say that if the rear lover brake lining if worn badly it will probably need replacement . If the rear bearing races are not badly worn , adjusting the rear brakes with the wheels on the floor will usually solve the rear brake drag . If the rear hub races are worn badly enough , the model A vendors have repair sleeves that can sometimes be pressed in by hand to remove slack or wear . Good luck with the setup . Its really not that difficult if you've got a good cool place to work .
 
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