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Like others have posted, my brakes recently started pulsing when slowing down briskly at highway speeds. With only 24k on the odometer, but nearing the end of the 3 year warranty, I decided to bring it to the dealer to fix the brakes and a few other annoyances. So the dealer calls yesterday and tells me the rotors are warped, but that Ford won't pay for repair. I argue with the service adviser and the service manager to no avail. I ask the service manager to call the regional Ford rep, so he does. Then he calls back and says that the rep denied paying for turning rotors. This after the rep asks the service manager if the truck has a fifth wheel hitch, camper tie-downs or hitch. I carry a slide-in camper and have a Torklift Superhitch on the truck, so they refuse to pay. They must be tired of paying for their lousy brakes, so they quit abiding by their own warranty. In reading the warranty, it says they don't cover "replacement of parts due to normal wear and tear" Then it goes on to list examples like brake pads, clutch linings, filters, etc. No mention of brake rotors. My main argument is that normal wear shouldn't cause rotors to warp. I have plenty of pad material left and I'm cautious about downshifting on grades to avoid riding the brakes (we're talking gas engine here) and always torque my lugnuts correctly with a torque wrench. So I can't think of any reason for rotors to warp unless there's a defect. What's everyone's thoughts on this? I'm ready to file some complaints with the Better Business Bureau and the State Attorney General's office. |
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Mine warp every 15k miles. I don't tow all that much or carry a camper. I managed to get my dealer to install new rotors at 35k miles, but they're warped again now. I would really like to find a way to fix this. |
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Drilled Rotors! Mo |
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Sorry to say most of the rotors and pads that are being put on these cars and trucks are not worth a rats rear end, I went through it with my GMC and finally got fed up with it and took everything off that General Motors put on and I mean everything and threw all the junk away, then I went out and bought top of the line Raybestos pads- shoes-rotors-drums-calipers and all my headaches went away for good, and like the fellow above is saying when my front brakes on this Ford start to give me trouble or when they cant be cut any more I'm going to go the drilled rotor route. |
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I don't think that you want drilled rotors, but you do want slotted rotors. The drill holes can allow stress cracks to form and propagate. That's bad. Slots allow the gasses from between the pads and rotors to escape. That's good. The metal is the problem. It won't take the heat. look at: www.appliedrotortechnology.com www.frozenrotors.com |
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Hey thanks for the line on those two companies,I checked them both out and I think I will be using the place in Minnesota, the only thing I'm wondering about is if the cold tempering makes the rotors so hard just how in the heck do you find a place that can cut them when you need to get it done?. and your rite about the slotted cuts I can see where they would be and advantage by acting as little air scoops to cool the rotor down. |
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The scoops are not so much for cooling but to let out the gasses. As the rotors wear against the pads, you are actually burning a little of the pad off. This burning releases gases that can build up between the pad and the rotors during braking, sort of lifting the pad off of the rotors. That is why disc brakes fade during repeated hard stops, the pads are not touching the rotors. The slots help to clear these gasses out, allow them to escape. These are not very deep. They can't be or you weaken the rotor. |
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OK, again. Rotors don't warp causing pulsation, they wear unevenly (out of parallel rubbing surfaces) during non braking (running down the road) due to a slight drag of the calipers from either the slides or pistons not moving as well as they should. Rotors that have been resurfaced so they have too high a lateral runout, hubs that are bent (hitting curbs / potholes), or improper torquing (stress warp) will cause the issue to happen to a greater extent. Calipers are the main cause of the issue and are rarely serviced. Per Ford, they only have to do the brakes within 12k. A good working relationship with a service department will get it done within the 36k, but a repeat problem first looked at under 12k will usually always get reworked. But if the calipers aren't changed, and none of the manufacturers authorize this expense, the pulsation generally comes back. You can use an abrasive racing or European type pads to wear true the rotors, but if the lateral runout is too high, pulsing comes quick. Otherwise you just wear away the service life of the rotors and most likely need to replace the rotors when the OE type pads would have allowed a resurfacing. Ford, and the other US manufacturers have a warranty rate on this issue of about 5% combined. |
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Quote: Sorry, but do rotors warp or don't they? In the 1st sentence you say rotors don't warp, then you say rotors can stress warp. I am confused. I think that you probably know your stuff, but your theory does not fully explain why some people get pulsation with heavy use (towing, hauling heavy loads) in very few miles (15,000) while others in light service go 40,000 - 50,000 miles with no problems. If pad drag is the issue, that variable is independent of load, but dependent on miles driven, isn't it? Also, if pad drag is the issue, then while are treatments such as cross-drilling, that help keep the rotors cool, help? The cryo treatment also seems to help the pulsation problem, but seems to me to be of little effect on pad drag. I am not trying to disagree with you, you very well may be correct, but I don't know the answers, so I am asking the questions. If proper caliper care is the answer, what should we be doing? |
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Be sure when re-assembling the brakes that the "sliding surfaces" are cleaned, and then I use "sure Lube"...This will keep the surfaces free from sticking.. The torque values on the lug nuts need to be even and evenly torqued.. When the brakes are hot, try not to drive thru cold water or wash the wheel areas until they have cooled... |
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I still do not understand. Can the rotors warp or not? If they can, the why does not heat make them warp? The calipers get hot! Is there some sort of high temp lube that you should use? I am thinking something like anti-seize. |
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Harald Had similar problem with my F250, Ford replaced the front rotors at 3300 miles for vibration when braking. They turned the rotors about 22000 or so and then the problem came back about 38000. Since it was out of warranty by then I was hosed!! So, after some research I decided to have Cryogenically Treated rotors installed on the front end (slotted units). Also, installed new pads (Performance Friction Z-rated high performance). Replaced rear pads with same at the same time. Had my mechanic do it, cost $130 labor parts were about $475. Now have over 50K on the truck and stopping is smooth as a babies ---t!! |
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That is the point that I am trying to make. If the problem is not warped rotors, but rotors that are worn unevenly, then why does cry-treated seem to work? |
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jschira, I'm not trying to avoid a response, just don't have all the time to cover this with a detailed answer. I don't mind the debate about this at all. Let me replace the wording in stress warp to stress distortion and correct my brevity. Under very high temperatures, rotors will dish and change there shape. It's not permanent and you don't get into this critical range unless your running an Indy or Trans-Am type vehicle. Some rotors if they are poorly manufactured will have thin and thick areas of the rubbing discs (discs that the pads contact), which will heat up more during high speed and continuous braking, like in the mountains. This is known as hot judder and a different issue. You can also have pulsation from friction material transfer, where a thin layer of friction material deposits heavily on one area of the rotor. This is more likely with organic pads, and seen after a hot run like through the mountains and then happens after a cooling period. Goes away with a few more stops. 1990 Crown Vic and Towncars were bad with this. There are many reasons why the rotors wear unevenly. The common one is due to the pads touching the high lateral spot on the rotor when going down the highway. Whether the vehicle is towing, heavy hauling, or carrying a briefcase, if the vehicle sees a lot of highway miles this occurs. If the rotor has a very high lateral runout that exceeds the normal clearance of the pads to the rotor (caliper pull back) it can occur is less miles. This usually happens when the rotors get resurfaced, or if the wheels get improperly torqued and stress distorted. It also happens over time as the caliper piston seals loose their resiliency and do not retract as well. Same thing happens if there is some rust buildup within the tangential groove that the piston seals reside in. With caliper hang-up, there are many times during vehicle tests we can correct the problem by just removing the calipers, pushing the pistons back in and reinstalling. Here is a good example of this: Before and After . If the issue had been the pads, the temperature imbalance would have switched sides. But with the slides and pistons moved, the problem went away. If the lubrication is not where it should be, that simple procedure can take care of it. When someone puts on a new set of rotors and says this took care of the problem, I say maybe, unless you tested before and after the caliper pin sliding force and measured the degree of caliper piston seal rollback. This is a situation that is heavily dependent on driving style, and issues that are never measured. Next time a mechanic says the rotors are warped, ask him to give you the measurement in ten thousands of an inch. He won't even be able to show you the measurement at one thousands resolution. The word "warp" has been, excuse the pun, distorted in use to the point that many people take this situation as a known. I've never seen any tests that show cross drilling or cryogenics do anything for this. Never. One thing that these kits do is use Performance Friction pads or the like. A number of those formulas use an abrasive formulation (silicon carbide) to generate higher friction effectiveness. Hence my comment about wearing the rotors true. That is one way of taking care of the issue with the calipers or poorly installed / machined rotors. It's not without it's own set of problems though. And you need the rotors to have a very low lateral runout (<0.0015") to start out with or you'll end up with problems at the 7-10k mile range. The current over the counter Ford OE level rotors do this. We've used probably 300 of these rotors and none have been installed over 0.0010" TIR. I'm sure these A/M treated rotors are within that spec as well. If I have the time over the next week, I'll try to illustrate an example from the tests we and the other OE suppliers use to evaluate for this "warp" issue. As far as the calipers go, that can depend on the vehicle. The calipers on these trucks are rather complex in that they are twin piston (twice the chance of a piston seal issue), went through some slide pin issues, use tension anti-rattle clips, have had "loose" hub specs, and if you have an early year model, is more sensitive overall to this issue. The spring 2001 through spring 2003 models use a double stick (adhesive) insulator that adheres to the caliper fingers and pistons. You can't take the caliper off to lube the slides or clean / lube the pad fitment areas in the torque brackets without destroying the effectiveness of the noise insulators. But that is what I do with my calipers every spring after the bad weather has ended. Helps in the South as well. But then I get free pads. Some take that risk of possible noise generation. I realize this doesn't cover it all, but that requires a book and I'm trying to be brief. I'll just try to answer the questions as they come. |
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Not trying to debate, it is just that what you are saying runs counter to everything that I have ever heard. Still, the earth was considered flat . . . . So proper caliper maintenance will include pulling the calipers, removing the pads and making sure that the pistons move freely? Also lubing the sliding areas of the calipers? What sort of lube? The front pads on my X are a pain, with that anti-rattle clip. Hate the thought of taking those off periodically to make sure that the pistons are free. Rears aren't too bad. It also sounds like a caliper overhaul or replacement should occur periodically. Every 2-3 years? |
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If your doing your own brake repairs the only thing I can tell you is to make sure you use a good high quality high-temp anti-sease or the newer silicone brake lubrication on all your brake areas that move, just think this way if it slides, (metal on metal) put lube on it, and like the poster before me was trying to explain to you and its something I have found out with rotors and drums, you get what you pay for, meaning that a lot of the rotors and drums you buy are made in Mexico and China which I have found to be junk, stick with good quality U.S made brake parts like Raybestos. Edited by keystoneKid (03/10/03 12:43 AM) |
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jschira, I meant debate is a good way. This issue has been evolving over the last 12 years, and most likely will be for a lot longer. Originally everything was blamed on the friction materials. Then later it was the rotors and hubs. Now the evolution has gotten to the calipers. But as I stated, can be a number of things as well as the synergy between everything. If what makes you feel confident is to use the ART rotors and PF pads, then fine. Many people will take care of their pulsation problems with this. Many people fix their problems with new calipers. And some of both solutions do not, especially if the new set of calipers are no better. I've go about 40k on my truck with no pulsation and driving 90% on freeways, the driving style of this problem the majority of the time. Based on previous vehicles, I'll start seeing the issue at about 100k and will have about 50% pad life left if I don't touch the calipers at all. The best lube for the calipers is this. But any brands brake caliper grease would be good, just so it says it's silicone. I'll respond more later. |
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Will a shot of spray silicon lube work? I know not as good as grease, plenty thin, but the spray will work its way in better without disassembly. At the very least, it could force out moisture and help keep everything from rusting. Probably have to do this every few weeks. |
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Rust is the problem in this area (torque plates), but I'm nuts for taking the brakes apart once a year, I really couldn't justify going in there every few weeks and spraying it will silicone. Your not going to be able to do the slide pins that way though. And the caliper piston seals are just something you have to let ride, except for a minor push-back, which you can easily do when you rotate the tires. When I rotate my tires, after getting the axle up on jack-stands, I turn the wheels to see how much resistance there is to rotating them, which would tell me if the calipers were allowing the pads to drag (comparing one side to another). Takes some experience, but it's a good check. I also note between washes if one wheel on an axle has more dust then the other. After pulling the wheel, if I did not take the caliper apart due to having the double stick insulator, then I would pry back the caliper as though I was going to put in new pads. I use 2 screwdrivers between the rotor and the caliper bridge and move the caliper so there is about 1/4" gap between the pad and the rotor. Often I bleed the brake fluid at this time to get the dark, moisture contaminated fluid out of the system, I have the bleeder screw open and a 3/16" tube going to a jar. This is to prevent fluid and debris going back to the ABS controller. If I wasn't going to bleed the fluid, I limit the pry-back to 1/8". You also have to be careful with the screwdriver as to not scratch the rotor surface when doing this. I'll try to get a picture of this over the next few days. With the pistons retracted back a little, when they are pushed back out to the normal condition they will carry a little brake fluid with them for lube. But while there is clearance, I slide the caliper in and out on the side pins to check for binding. This also moves some of the lube in the pin area around so one area will not be dry. I then gravity bleed the one wheel I'm working on by removing the master cylinder cap and let fluid drain through the bleeder screw into the jar. I watch the reservoir to make sure I do not run out of fluid, but usually clear brake fluid comes out of the tube before this happens. Also while fluid is bleeding out, I tap the caliper with a small hammer to vibrate loose any air bubbles that may have formed within the caliper from overheated brake fluid. Sometimes fluid likes to hang up and you have to partially apply the brake pedal (about 2") just to get fluid moving. You don't want to fully stroke the M/C if it has not had it's fluid regularly changed, as an area of corrosion may have formed with the end of the M/C bore. Some people like to use a vac bleeder; I don't - I just let it gravity bleed. Then I move on to the next wheel. Yes, I'm nuts. The majority of owners of these vehicles never do anything like this and never have issues. |
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We all have to pick the battles that we want to fight. I am sort of anal about oil. As far as bleeding the brakes, I use the "pressurized" method. I have managed to train my wife in the lost art of pedal pumping. She has gotten so good that she can even fill the MC while I stay under the truck. She's a good sport. This starting being my job for my Dad when I was about 5 years old and my Mom refused to do it anymore. |
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Pulsing brakes
