Thickness of original brake pads
- Thread starter skyguy
- Start date
You probably started out with something under 1/2" of pad thickness. When you get close to 1/8th of an inch it's time to get them replaced. Disc systems don't care if the pad is gone or not. The pistons will continue pushing and pushing. I actually took a brake caliper system apart once and the inner side of the vented rotor was worn away completely and the piston was rubbing on the rotor spacers. When you get the work done unless you do it yourself here is some information. The brakes effectiveness depends on the pads and rotor mating perfectly. When that happens maximum friction is developed. Don't let anybody tell you that you don't need the rotors machined. They should always, always, always be machined. I even machined new rotors. Always get the best pad you can afford and they make different qualities. I used NAPA during my career as an automotive instructor. They seemed to keep up with changes and always had the top quality pad material that was available at the time. Remember that things do change and one size does not fit all. When doing brakes always get the best and do everything that is needed and more if necessary. If you need or want more information PM me and I'll try to help.
I'm offering this info so you get things done correctly and that you maintain a safe unit.
TeJay
I'm offering this info so you get things done correctly and that you maintain a safe unit.
TeJay
Ray LeTourneau
Senior Member - Past Moderator
So to clarify, Drum brakes use shoes and they are near 1/4" thick when new. Mine are currently close to 3/16 but the thickness varies a teensy bit.
Disc Brakes have pads and are 3/8" to 1/2" thick when new. Inner and outer pad wear may vary but both should be replaced at the same time.
I'm not even sure if riveted shoes or pads are even made any more. At least I haven't seen any in the last few years that I can remember.
Now I feel mush better.
Disc Brakes have pads and are 3/8" to 1/2" thick when new. Inner and outer pad wear may vary but both should be replaced at the same time.
I'm not even sure if riveted shoes or pads are even made any more. At least I haven't seen any in the last few years that I can remember.
Now I feel mush better.
Ray,
You are correct. Disc pads tend to wear more on the inside because that's where the piston is located. The piston pushed the inner pad against the rotor and the sliding caliper pulls the outer pad against the outside of the rotor. Common sense says that the pressure would be the same but the inner pads almost always wear more. Therefore always check the inner pad for wear. ALWAYS replace all pads at least on each axle. If I were doing two axles on my TT I'd always do both axles at the same time. When replacing pads ALWAYS, ALWAYS machine the rotors. Don't let anybody tell you otherwise.
Shoe or drum breaks will wear at a slight taper. The reason is because the shoes will pivot at the top. When that pivoting occurs the rotating drum will pull the shoe into the drum creating a wedging action that will result in a greater amount of pressure at the bottom which will cause more wear from bottom to top.
It used to be that a lot of shoes and pads were riveted. We don't find that as much unless you get into the larger vehicles. I guess the adhesives have gotten better over the years or their may be some other reasons that I;m not aware of.
TeJay
You are correct. Disc pads tend to wear more on the inside because that's where the piston is located. The piston pushed the inner pad against the rotor and the sliding caliper pulls the outer pad against the outside of the rotor. Common sense says that the pressure would be the same but the inner pads almost always wear more. Therefore always check the inner pad for wear. ALWAYS replace all pads at least on each axle. If I were doing two axles on my TT I'd always do both axles at the same time. When replacing pads ALWAYS, ALWAYS machine the rotors. Don't let anybody tell you otherwise.
Shoe or drum breaks will wear at a slight taper. The reason is because the shoes will pivot at the top. When that pivoting occurs the rotating drum will pull the shoe into the drum creating a wedging action that will result in a greater amount of pressure at the bottom which will cause more wear from bottom to top.
It used to be that a lot of shoes and pads were riveted. We don't find that as much unless you get into the larger vehicles. I guess the adhesives have gotten better over the years or their may be some other reasons that I;m not aware of.
TeJay
traveler44
Well-known member
The new brake shoes on the bighorn were not very thick- maybe 3/16"- but what I did notice was that the drum was made out of a very soft material, maybe cast iron, and they looked like they were wearing quicker than the shoes were. I am wondering if we can get better drums when they need replacement. Like when you buy auto. parts sometimes you have a choice of six month- one year- or lifetime warranted parts? Tom
The drums probably come from more than one foundry. Ours after three years show very little wear. We do have the large drums however that come with the 8K axles.
Hi,
Traverler44, You are correct about the differences in cast iron. The quality of cast iron is different and it does affect the wear of the drum. Technically speaking the cast rion drum or rotor shoud wear less than the pads because the pads are designed to be softer than the surface that they rub against. However some manufacturers of pad material don't care about that. Sometime they will give a lifetime warranty for their pads/shoes. They know they are harder and the rotor/drum will wear before their stuff wears and since their brake material is still good you buy new rotors or drums. That's not how it's supposed to work. The drum/rotor will wear but it's not supposed to wear more than the brake material. What can you do???? My suggestion is to go to NAPA when and if you have to purchase drums/rotors. As I told my students. The smaller parts stores don't have a National reputation to deal with, NAPA does. Dealers will sell you for the most part OEM (original equipment manufacturer) specifications stuff. That should mean that it is as good as the original. Parts houses don't do that. They will often have 2-5 price ranges and that will determine the warranty and the quality. If you walk into a parts store to buy they don't want you walking out. If they hit you with a price if it is to much they will hit you with a cheaper price. It's been a few years but prices for disc pads might vary from $20 to $60 for the same application. What's the difference??? Quality, quality, quality. When it comes to brake material I ask of OEM or better at the NAPA store. They above all others seemed to keep up with the quality aspect. I'm sure their are others stores but since I used NAPA I didn't look beyond. There is also a vast difference in the quality of cast iron. The differences in rotors would boggle your mind. you don't have to worry just ask for a rotor that meet or exceedes OEM specs and they will provide it for you. It may not be cheap but it should and will be the best they can offer. I'll close by telling you one more story. I ordered an exhaust for a vehicle years ago. I went in to pick it up and it was slightly different and would not work. When they found the correct one the difference in weight was at least double. I asked why and they told me that the first one was to OEM specs and was considerable thicker. The other one was not and was a lot thinner. The average person would not know the difference but you can bet the the thinner exhaust would not last nearly as long as the other. That's when I realized that parts houses do manufacturer parts that are less than OEM specs. It's all about the bottom line. When it comes to brakes I want the best and I'll pay what ever I have to to get it. As far as I am concerned the dealers offer quality and so does NAPA. At the dealer you are also paying for the name. No I don't own stock in NAPA.
TeJay
Traverler44, You are correct about the differences in cast iron. The quality of cast iron is different and it does affect the wear of the drum. Technically speaking the cast rion drum or rotor shoud wear less than the pads because the pads are designed to be softer than the surface that they rub against. However some manufacturers of pad material don't care about that. Sometime they will give a lifetime warranty for their pads/shoes. They know they are harder and the rotor/drum will wear before their stuff wears and since their brake material is still good you buy new rotors or drums. That's not how it's supposed to work. The drum/rotor will wear but it's not supposed to wear more than the brake material. What can you do???? My suggestion is to go to NAPA when and if you have to purchase drums/rotors. As I told my students. The smaller parts stores don't have a National reputation to deal with, NAPA does. Dealers will sell you for the most part OEM (original equipment manufacturer) specifications stuff. That should mean that it is as good as the original. Parts houses don't do that. They will often have 2-5 price ranges and that will determine the warranty and the quality. If you walk into a parts store to buy they don't want you walking out. If they hit you with a price if it is to much they will hit you with a cheaper price. It's been a few years but prices for disc pads might vary from $20 to $60 for the same application. What's the difference??? Quality, quality, quality. When it comes to brake material I ask of OEM or better at the NAPA store. They above all others seemed to keep up with the quality aspect. I'm sure their are others stores but since I used NAPA I didn't look beyond. There is also a vast difference in the quality of cast iron. The differences in rotors would boggle your mind. you don't have to worry just ask for a rotor that meet or exceedes OEM specs and they will provide it for you. It may not be cheap but it should and will be the best they can offer. I'll close by telling you one more story. I ordered an exhaust for a vehicle years ago. I went in to pick it up and it was slightly different and would not work. When they found the correct one the difference in weight was at least double. I asked why and they told me that the first one was to OEM specs and was considerable thicker. The other one was not and was a lot thinner. The average person would not know the difference but you can bet the the thinner exhaust would not last nearly as long as the other. That's when I realized that parts houses do manufacturer parts that are less than OEM specs. It's all about the bottom line. When it comes to brakes I want the best and I'll pay what ever I have to to get it. As far as I am concerned the dealers offer quality and so does NAPA. At the dealer you are also paying for the name. No I don't own stock in NAPA.
TeJay
traveler44
Well-known member
Hi. Thanks for the replies about the soft cast brake drums. I will start pulling drums off soon to inspect the brakes and pack the bearings. If the drums show too much wear I will shop around for new ones. Thanks again for the advice. Tom
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