Just installed all new drum brake pads, and learned about primary secondary pads the hard way. So the rears have an obvious primary and secondary, and I luckily put the big to the back so they should be good. The fronts however do not have a small lining and big lining, they are all the same length. They do however have 2 thick shoes and 2 thinner shoes. So I’m thinking I should just put the thicker material shoe towards the rear? Thank you in advance Ryan
After I looked closer there is a longer and shorter pad, so I installed big to the back. All good now
Not being critical. Just trying to be informative. If you have drum brakes, then you have brake shoes. If you have disc brakes, then you have brake pads. Let the criticism begin.
Nope, you are 100% correct. I have the same issue with my guys at work. I’m a stickler for correct terminology.
Unless it's a Ford or any other car with the shoes held at the bottom with a bolt and not self energizing. Then the long shoe goes on the front.
I don't know if I'd say that the trailing shoe contacts the drum first, but the anchor pin at the top of the backing plate prevents the trailing shoe from rotating with the drum when the brakes are applied. The following is quoted from the Hemmings.com website. "When the operator steps on the brake pedal, pressure applied by the hydraulic wheel cylinder pushes the upper parts of the shoes outward. The primary shoe wedges against the rotating drum while the drum tries to pull the shoe along with it. This self-energizing action pulls the shoe even more tightly against the drum, multiplying the braking force. As the primary shoe shifts inside the drum, its lower "foot" pushes against the adjuster, applying force to the secondary shoe and forcing it outward against the drum." More details at the link below. https://www.hemmings.com/stories/article/duo-servo-brakes For that matter, did a stock '56 Mercury use duo-servo, self-energizing brakes?
On servo acting brakes the primary or front or short shoe has a lighter return spring so it contacts the drum first which then apply the secondary or rear shoe…
If one end of each of the shoes are fastened to the backing plate and are not free for one shoe to push the other shoe, yes it applies to Mopars.
once upon a time the secondary shoes used to be thicker lining as they do most of the work. However I think that has mostly changed in the last few years
Harmonic Balancer? Sadly, I would hazard you a guess that most of the guys I work with could not tell you the difference between primary and secondary hydraulic brake shoes. Granted, we deal with primarily air brakes and hydraulic disc brakes, but to me primary and secondary brake shoes are basic automotive theory, however, and this just occurred to me, how long has it been since the OE’s used self energizing drum brakes? I just realized I’m a dinosaur. All that being said, Little Truckdoctor will certainly know the difference in brake shoes and self energizing vs Huck style brakes. Our 3100 still has Huck style on it, for now.
These were duralast brake shoes, the rear ones were same thickness all around but did have a definite longer and shorter shoe. The fronts, after I inspected them better, had a longer and shorter shoe but also the secondary shoes were about 1/8” thicker. I first put both secondary’s on one side, when I went to put the drums back on one side went too easy, the other very hard. That’s when I knew I did something wrong
I would hope we have motors in our rides. Otherwise what do General Motors and the Ford Motor Company put in their cars for propulsion?
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