Twenty six years ago I had just that experience in an International Harvester Travelall on top of the High Rise Bridge in the heart of New Orleans. Over many years of use, a brake line wore through and began spewing brake fluid onto the exhaust system each time I stepped on the brakes, creating a great white cloud. The traffic was the usual bumper to bumper thing, and I feared what might lay ahead prior to getting off the steep bridge. I stepped on the emergency brake pedal to hold back my truck on the down hill side and pace the surrounding traffic. All ended well, and my blood pressure eventually went down...
Some Chrysler products back then had the emergency brake on the driveshaft as I recall. The problem is that without 4-wheel braking, eventually the two brakes heat up and burn and then you have nothing. On older automatics, you could throw them in reverse at some pretty high speeds, but I don't think they let you do that anymore. True you eat a transmission but that's better than eating a tree IMO.
Gentlemen, why do you suppose EVERY carmaker and parts manufacturer that I'm aware of lists it as a parking brake? It's designed to hold a stationary vehicle from rolling, and take load off the parking pawl in automatic transmissions/transaxles.
Since 1967, vehicles have been equipped with tandem master cylinders and dual brake hydraulic systems to provide redundancy in the event of a brake hydraulic failure. If a line or hose fails, half of the hydraulic system remains operational. As every 2nd year apprentice here knows, if rear or 4 wheel drive, front or rear brakes will be still work, depending on which line failed. If front wheel drive, one front and the oppopsite rear brake will still work, since we all know that the former uses a front/rear hydraulic split and the latter uses a diagonal split. However, the brake pedal will be significantly lower, leaving drivers with the perception that the brake system has completely failed. It hasn't, but braking has been reduced. To suggest that the parking brake will be more effective in slowing or stopping the vehicle than a partially operational hydraulic system indicates a profound lack of knowledge of brake hydraulic systems. You might want to sit in on my next basic brake course. We cover all failure modes, including those with quick take-up master cylinders.
Federal Motor Vehicle Safety Standard No. 105 (superseded by Standard No. 135): Hydraulic and Electric Brake Systems
Scope and Purpose:
This standard specifies requirements for vehicles equipped with hydraulic and electric service brake systems, and associated parking brake systems. The purpose of this standard is to insure safe braking performance under normal and emergency conditions.
Application:
Hydraulically braked or electrically braked passenger cars, multipurpose passenger vehicles, trucks, and buses with a GVWR greater than 3,500 kg (7,716 lb)
Btw, there is one scenario where a single hydraulic failure could possibly lead to total loss of braking. Any takers?
"...the brake pedal will be significantly lower, leaving drivers with the perception that the brake system has completely failed."
I suspect that is a major reason that the parking brake is from time to time employed as an emergency brake. Combine a master cylinder failure with a loss of vacuum in the power brakes and the driver may get scared enough to step on the parking brake, or jerk on the lever, whichever is pertinent.
Aside from hydraulic fluid loss in both compartments of a dual master cylinder, I can't think of how one single event could cause total brake failure. So tell me.
Overheated brake fluid from dragging brake will cause complete brake failure, pedal right to floor and zero brake action. Personal experience with a 1990 vehicle, sure suprised me.
Under normal braking the primary piston (closer to booster) is applied mechanically by a pushrod from the pedal or booster. As the primary piston travels down it's bore it closes off it's compensating port, then starts building pressure betwen it and the inverted secondary cup on the rear of the secondary piston. Thus, the secondary piston is normally applied by primary system pressure. If a failure occurs in the secondary side of the hydraulic system, initial primary piston movement will push the secondary piston to the end of the bore. Now the primary piston has to travel further before it can develop pressure. If the brake hydraulic system hasn't been flushed every 3 years, which is usually the case because most customers have never heard the word "hygroscopic", there's probably moisture induced corrosion and rust scabs in the previously unswept portion of the m/c bores. This can damage the primary piston's primary cup, resulting in a loss of primary system pressure.
Something I tell every basic brake class when we get into m/c failures, if you get one in with a leaking brake line and the pedal's gone down, make sure you tell the customer up front that it might need a m/c afterwards due to piston seal damage from a scabby bore. If it doesn't, you're a hero. If it does and you didn't mention the possibility beforehand, all he knows is the pedal went down, you told him it was a leaking line, and now you're trying to gouge him for additional repairs.
This all conjures up the developing electric brake solution. Perhaps hydraulic brakes will just be phased out over time. But meanwhile, we will continue to repair them.
I believe it is called a parking brake beause its primary design is to hold the vehicle still while the vehicle is in park, as an auto trans (I believe) only has a steel pin jammed into the trans to stop forward motion, and that pin can be sheared off if car is placed on a steep incline, and if pin breaks, car is effectively in neutral...it is also called a parking brake probably for liability purposes...the fact that it is engageable while in motion (i.e if your brakes fail) has led us to call it an emergency brake, simply because it is the only brake you have left, except for downshifting the transmission and/or turning off the engine (in which case you will lose power steering unless it has a power reserve like the Toyota 4-Runner)... THEY call it a parking brake, WE call it emergency brake...(you say tomato, I say tomato)...
We have a 2003 Hyundai Accent GL with 11,300 miles on it. We took it into service because of a clicking noise coming from the brakes. Upon inspection of the front disk brakes, the service manager pointed to corrosion on the perimeter of the rotors and the caliper slides on both front brakes. The passenger's calipers were "frozen", while the driver's calipers were just about to freeze. The service manager indicated that the rotors and pads for both brakes were in excellent condition as to surface wear. The clicking noise was caused by the corrosion on the perimeter of the passenger rotor as it scraped against the inside of the caliper assembly (there was a corresponding fresh metal scratch easily visible).
Is it "normal" for Hyundai brake assemblies to fail due to rust at 11,300 miles? If this is a "normal" situation with Hyundai automobiles, its definitely an indication that we would not be recommending them to any of our friends. The service manager also suggested that we come in to have the rust and corrosion on the brakes removed on a yearly basis. Is this "normal" for Hyundai brakes?
We were told that these items were no longer covered under the warranty program (the Accent was purchased in October 2003). What is the "normal" expected lifetime of these parts? Should we be pursuing reimbursement from Hyundai (or the dealer) for the cost of the parts and labor for this repair? Could this be a manufacturer's defect?
Judging by your name, you are in the northcountry "salt belt" The salty winter roads can corrode brake parts at an alarming rate.
Also keep in mind that Hyundai/Kia are cheep automobiles to begin with. One reason they are so inexpensive is because of the things you DO NOT SEE. The steel has a high pecent of poorly-recycled (to make it cheep) metals in it. The bodys rust out like a 1970 chevy and I am sure the brakes will too.
Since you saved so much $$ purchansing a Hyundai, you can use the cash you saved to get the brakes fixed. ;-)
Having a thick layer of rust around the perimitor of the rotors is a common occourance in the salt-belt. I usually just "turn" the rotors in -place with a steel bit to remove the rust. Installing HIGH QUALITY (ie..Bendix) rotors will elimintate that problem.
My 1970s and 1980s cars had brake rotors that froze up all the time. Even though I do all my own brake work, it was not worth it to install the same cheep OE equipment. I always shopped the autoparts stores for LIFETIME WARANTEE brake parts and installed those. Even if those parts did need to be replaced every 2-3 years, at least THEY coverd the cost of the parts.
You're right about the salt on the winter roads, of course. Our concern was that this happened at 11,300 miles. It just didn't seem right that such a critical part which is going to be exposed to water and salt anyway, would fail so soon. We'd also not seen any other reports of such an early "death" which further grabbed our attention. Our son, for example, has the same model, purchased one year earlier, and driven in the same conditions but has had no problems -- and he has many more miles on his than we had on ours.
I was going to wait for warmer weather to revisit the brakes and, as you've suggested consider replacing them with something of better quality. Needless to say, we're more than a little disappointed with the quality of this rather important part of the vehicle.
I would also tend to agree! I think the only thing you probably could have done different after each winter was to tear down each wheel and cleaned the back of the wheels, wheel wells, shot brake cleaner and scrubbed: calipers and rotors etc, but that sounds too much like WORK! Benign neglect can have its advantages!
When it comes to "frozen calipers", the milage is not a big contributer. In fact LESS usage would contribute to this happening. Roadsalt cannot penetrate the seals and get in the calipers.
Do not forget that the biggest contributer to "frozen calipers" is contaminated brake fluid. All brake fluid should be changed every 2 years to reduce caliper freezups.
You may find with calipers, there is no "better quality" all you will find is "rebuilt originals".
When I mentioned better-quality, I was talking about the ROTORS which can vary widely in quality based on the material they are made of.
Your vehicle has seen at least 2 winters of salt-laden roads. That is plenty of salt to make your rotors start to rust.
Well okay, my answer is still basically the same....you got salted roads, you got problems. It's a harsh environment. Maybe this particular car's design traps salt and moisture more than most, I don't know, but if you think about what brake calipers have to go through on slushy, salted roads, it's a wonder they survive two years at all.
So is this repair "normal"? No, I wouldn't say that. Can it happen now and then? Sure.
Is there any performance difference in ceramic pads, i.e stopping power...also, are they noisy and do they cost much more, and (finally) are they readilt available or are they condered racing hi performance parts???
There are "ceramic based" pads available for most vehicles. They are NOT considerd racing pads (True racing pads ONLY work after they have been used enough to warm them up.... not good for normal road use.)
A common "ceramic based" pad is available thru NAPA as their "Ceramix" brand. (Made by Raybestos for NAPA) Virtually all friction-materal manufacturers have some "ceramic based" pad in their lineup. (Raybestos "QS" is their own Ceramic pad)
The performance difference for "ceramic based" pads include... very quiet(no squeels), Low dusting, and Long life. Some folks say that they are a bit more aggressive on rotors, but I have NEVER worn out a rotor. (mine always rust into oblivion.)
If you telephone any auto-parts store and ask for pads for your vehicle, they will offer you AT LEAST 3 "grades" of pads. The cheepest ones will make so much black dust that you will never be able to keep your wheels clean.
If you click on the links below you will see a comparison between several types of friction material.
I noticed my ABS light on my 97 honda prelude came on today and then 30 seconds after I noticed it my car shut down. It was as if I put the car in park and turn the car off. I had my ABS light come on in my cavalier back in the day but it never caused it to shut down, the brakes just had problems catching. I know the signs if there is something wrong with the brakes, but they feel fine. There isn't a difference in braking. Not to mention my brakes were just changed in the fall. Why would the ABS cause the car to shut down if the brakes are fine?
I own a 1999 Honda Accord V6 with a little over 100K miles. I had front/read brake rotors/pads replaced for the second time in the life of the car a little over 5000 miles ago. Since then, approx every 1200 miles I have developed steering wheel shake when applying moderate brake pressure at speeds between 25 - 10 mph. I had a sticking brake pad in the passenger rear, and replaced the rear rotors/pad again. After another 1200 miles or so the problem returned. I then had all four rotors shaved and again, the problem disappeared, only to come back about in about 1000 miles. I did not use Honda parts (used NAPA) parts, in the end, using NAPA's best rotors and pads. I would like some suggestions as to the root cause of this problem, and if there is any test to absolutely determine what it is. I have been given suggestions from a misaligned belt in my tires (not likely, since they are new and have been just rotated and balanced) to front wheel bearings about to go bad. Any help would be most appreciated. DWW
I sounds as if you are describing rotors that are warping. Since it is the STEERING WHEEL that is shaking, that points to the FRONT end as the issue here.
If you are suggesting that replacing REAR components make the STEERING WHEEL shake go away, then you are describing a near mechanical impossiblity. !?!? (I am assuming you DO NOT have 4-wheel steering)
As with all mechanical problems, one must identify all of the clues (symptoms) no matter how diverse they seem. I have over 30 years of troubleshooting complex mechanical systems and have learned that once the ROOT of the problem is found, all the clues make sense. (hindsight 8-)
With that said, are there any other symptoms besides shaking steering wheel that you can elaberate on. Does it happen only when braking? Does a bumpy road exagerate it? Does the brake-pedal pulse? Can your passengers feel it in their seat? Is it more pronounced while turning to left or right?
If it is warping rotors, there are several things that can cause new brake rotors to warp prematurly; 1) Over-torquing lug nuts 2) Not seasoning the rotors 3) Dragging brake caliper 4) Cr@ppy rotors
Any GOOD! mechanic would be able to do some hands-on testing of the front-end components to determine if you have dragging calipers, excessive runout, bearing endplay, loose tie-rods,...or any other issues that may be contributing to the situation.
Just get new rotors, and good ones. I don't know why folks are turning rotors on Japanese dars--they are so cheap to buy new. If you turn a rotor, it's thinner, and will not dissipate heat as well as before.
Yeah, I would second the recommendation to not "rotor" turn. It is absolutely amazing for example that Honda and Toyota have not been called on brakes that have worn down in many less miles than if a "better quality" combination was used. This is not to ignore that German marquees such as BMW, VW and MB, when sets of brake pads need changing usually change the rotors also.
Is it my imagination, or is the practice of turning rotors far more problematic in brake jobs than it was fifteen and more years ago? It seemed to work years ago, but recent brake systems seem to be negatively affected by resurfaced disks. I've had it happen to me, and several people I know concur in view of similar experiences.
NO, it is not at all in your imagination. The proof is really in the pudding and unless you have those 15 year old arcane publications (like shop manuals ), the evidence has long since probably been removed!
So for example in one of my publications for a vehicle:
technical data, brakes
Front brake pad thickness is 14MM or .551. The wear limit is 7mm or .276.
On the front brake disc, thickness it is 22MM or .866. The wear limit is 19mm or .748
So if most folks eyes aren't glazed over by now, lets do the math.
So you have basically two wearing surfaces one rubbing off and providing friction(pads) and the other rubbing off and disipating heat (hence having to have a certain MASS to disipate in specification heat): rotor.
Brake pads can wear (14mm-7mm= or .551-.276) 7mm/.275
Brake rotors can wear (22mm-19mm= or .866-.748) 3mm /.118
The upshot is when the it is time to change brake pads, the rotors do not have enough "wearable" material to last the mileage the last set of pads probably did before it hits the wear limits (on the new set of pads).
So turning them (to true or zero run out them) CAN remove too much "wearable" material to leave enough buffer material before the new pads are KAPUT.
when I was working on cars in the 70s and 80s, Japanese imports were almost unheard of, and the imports were mostly European...the Big 3 had over, I guess, 80% or more of the USA market...the disc brake rotors used on American cars were massive and thick, and could often be turned twice before they were too thin for safe use...nobody worried about weight because gas was not expensive, and the cars were "more metal is better"...so, us older guys have always recommended to NEVER change disc pads without trimming the rotors because the glaze must be removed (which can be dome poorly with sandpaper and only the cheap folks would do it), and, more importantly, the rotor warpage was removed and it now ran at 90 degrees with no waving or warping...so, the new pads were now running on a true perpendicular surface...but us old guys need to change, and recognize that the new cars must save weight, and so the rotors are just thick enough to get by for, say, 20K to 50K miles, and that a brake job now consists of new pads and new rotors, especially since the hub is now detached from the rotor, so the replacement cost of the rotor is actually quite inexpensive, but, we shall cut no more rotors in brake jobs...
It's really an appealing concept. I went through fits with a Pathfinder after the rotors were turned. I hope in the future to be able to just change pads when old rotors are in good condition, and to replace the rotors that otherwise would need turning.
There are of course some interesting anomolies. I had a 1987 TLC that routinely got app 60,000 miles between pads. (daily use;business and delivery vehicle to boot) 2 sets of rotors in app 250k miles (oem and replacement) Subsequent year TLC' max 40-45 k between pads, with rotors touch and go.
Friend's Porsche model's literally eat brake pads (and rotors) yet Porsche is known for having "bullet proof" pads and rotors. Brother in laws BMW 330i eats brake pads and rotors. Corvette Z06 which has been written up as having "less than Porsche brakes" have more than half the pads left with 68,000 miles (driven hard and put away wet, so to speak) rotors still have close to new thickness specifications.
I have VW Jetta TDI brakes which have developed a reputation for short lasting pads and rotors are on track at 49,000 miles to go to at least 100-150k miles fronts and 100-120k mile rears.
Also there are some auto stores that offer lifetime gurantees on very high quality brake pads (Performance Friction Z pads) to name one. All they require within wear specs, you bring back the old worn ones and they will give you a new set.
Porsche and BMW expects you to use up pads and rotors, because you're supposed to drive the hell out of these cars. You will never defeat the brakes on these cars in street driving. So, even if you have to replace pads and rotors more frequently say than a mini-van, it's not a "defect", but rather an engineering priority that you have to live with. Besides, I don't think the pad/rotor mileage on these cars is any worse than any other car driven very very hard. A Volvo putting around at 55 mph is going to be very easy on brakes unless the driver is really ham-footed (equivalent of ham-fisted).
Some of the new exotic road-going/trackable Porsches (new GTs) use ceramic rotors that cost $8,500.....EACH! But then, for stopping at 210 mph or so, what's the problem with that?
Somehow I suspect that those $8500 disks are just, oh... let's say, a tiny bit overpriced. And further, I'll go way out on a limb and say that there is a possibility that less expensive brakes could be used, and to great satisfaction. Can you forgive me this indiscretion? (:o]
Well of course I forgive you, but I want to tell you they are magnificent to look at--I've seen them.
Personally for the cost of new Porsche GT, I'm not going to quibble over a lousy $16,000 if I can stop ten feet sooner than a Corvette or Ferrari, especially if 5 of those 10 feet are occupied by a brick wall.
As you are no doubt aware, as one achieves perfection in anything, the last couple percentage points are astronomically expensive. It costs more than 10% to go from 200 mph to 220 mph, and a couple pounds off an already light mountain bike is going to be more than the cost per pound of the heavier bike.
Conversely, and getting back on topic a bit more, saving $5 by installing inferior brake rotors when you are building 500,000 of something is very very tempting for an automaker.
I re read my post and recall saying there were "anomolies".
Are there defects or problems? Yes and No.
I don't think that remedy for my Toyota Landcruiser's would be applied to me unless it was demostrated in court. (the money I received for 4 sets of Toyota Landcruiser pads and brake rotors)
To me and I would hope to others, it is fairly logic that if one wants to track or drive hard that one should be prepared to change out pads and rotors on a fairly frequent basis compared to one who does not. Very simply, this is the real price for "flogging" the vehicle.
The concern, as folks have expressed it is when they do not tend to flog the vehicle BUT still have to change the rotors and brakes very frequently!?
I think the complaints you are hearing are either exceptions or the people are driving harder than they think they are...not uncommon in a BMW or Porsche...."oh, was I doing 100?"
I never had a car where it didn't eat brakes. Every car I ever owned. So obviously I'M THE PROBLEM!
Had brake pads replaced by small shop vesus the "big shop" who wanted to replace everything, pads, rotors, brake sensors, all four wheels, $1,800...compared to small guy who saw 50% pad remaining on rears and pristine rotors...$170... small shop replaced front pads, ever since then high-pitched screaming from front right tire, beginning at 35-40 mph with no effect from braking...winds down with deceleration to a stop...have had relubing and clips checked, new set of brake pads, new rotor, still the sound continues, mechanic is at a loss and looking for advice from mechanics, so I'm doing my own research...HELP???
Hi. Try not to do duplicate posts. I think we're talking about this problem in the Boxster forum. I did speak with a Porsche shop for you and they had no idea.
Is it possible the dust shield was bent slightly and is contacting the rotor? This should be easy to spot, and if your mechanic has redone the brakes again he probably would have noticed it. I had this happen once, it doesn't take much contact to make quite a racket! Just a thought.
Apparently there's a design flaw in (at least) the 2000 SLK. The metal contacts for the brake lights are either the wrong type of metal, have the wrong type of rustproofing or both. After some time the contact between the brake light bulb and where that bulb is inserted into the light framework is burned away/corroded. This happens first to the brake lights which are either higher amperage or used more often. What happens is the brake light stops working and a warning light comes on on the dashboard. If you remove the bulb you find it intact. The Mercedes dealer will charge $800 each to replace the rear light assembly, but the issue can be solved for a little less than 5 cents plus labor if you can use a soldering iron. I felt I just had to share this with others.
Remove the rear brake light assembly by opening the plastic covers inside the trunk. The brake light assembly is attached with four metric nuts which are a little hard to get to, but the only fasteners for the whole assembly. There may be other components behind the plastic cover that make the brake assembly tough to get to, but they can be removed without removing screws/nuts.
Unplug the brake light assembly, remove the light bulb and examine the place where the brake light plugs into the back of the assembly. On either side where the light bulb holder contacts the assembly you will see a darkened/corroded area. This corrosion/lost metal are preventing the bulb from getting power. Scrape the corrosion away and put a layer of solder over the pitted metal so that the bulb will get good contact.
Replace the bulb and assembly. Plug the assembly back into the car and close the plastic panels. Spend the $1,600 (!!) you just saved on something nice. Send me an email saying how wonderful I am.
Hope this helps someone - I'm quite glad I figured it out and couldn't find it anywhere else.
Did the bending of the dust shield help? I have this same problem with my 2000 Tacoma. Seems to build up a lot of dust on the front wheels (maybe due to the sheild being bent as well?), and the sound gets much worse after it rains.
Comments
Since 1967, vehicles have been equipped with tandem master cylinders and dual brake hydraulic systems to provide redundancy in the event of a brake hydraulic failure. If a line or hose fails, half of the hydraulic system remains operational. As every 2nd year apprentice here knows, if rear or 4 wheel drive, front or rear brakes will be still work, depending on which line failed. If front wheel drive, one front and the oppopsite rear brake will still work, since we all know that the former uses a front/rear hydraulic split and the latter uses a diagonal split. However, the brake pedal will be significantly lower, leaving drivers with the perception that the brake system has completely failed. It hasn't, but braking has been reduced. To suggest that the parking brake will be more effective in slowing or stopping the vehicle than a partially operational hydraulic system indicates a profound lack of knowledge of brake hydraulic systems. You might want to sit in on my next basic brake course. We cover all failure modes, including those with quick take-up master cylinders.
Federal Motor Vehicle Safety Standard No. 105 (superseded by Standard No. 135): Hydraulic and Electric Brake Systems
Scope and Purpose:
This standard specifies requirements for vehicles equipped with hydraulic and electric service brake systems, and associated parking brake systems. The purpose of this standard is to insure safe braking performance under normal and emergency conditions.
Application:
Hydraulically braked or electrically braked passenger cars, multipurpose passenger vehicles, trucks, and buses with a GVWR greater than 3,500 kg (7,716 lb)
Btw, there is one scenario where a single hydraulic failure could possibly lead to total loss of braking. Any takers?
I suspect that is a major reason that the parking brake is from time to time employed as an emergency brake. Combine a master cylinder failure with a loss of vacuum in the power brakes and the driver may get scared enough to step on the parking brake, or jerk on the lever, whichever is pertinent.
Something I tell every basic brake class when we get into m/c failures, if you get one in with a leaking brake line and the pedal's gone down, make sure you tell the customer up front that it might need a m/c afterwards due to piston seal damage from a scabby bore. If it doesn't, you're a hero. If it does and you didn't mention the possibility beforehand, all he knows is the pedal went down, you told him it was a leaking line, and now you're trying to gouge him for additional repairs.
What is the difference in European (import) brake rotors/disks and american brake rotors/disks? (I.E. Honda/VW)
Is it "normal" for Hyundai brake assemblies to fail due to rust at 11,300 miles? If this is a "normal" situation with Hyundai automobiles, its definitely an indication that we would not be recommending them to any of our friends. The service manager also suggested that we come in to have the rust and corrosion on the brakes removed on a yearly basis. Is this "normal" for Hyundai brakes?
We were told that these items were no longer covered under the warranty program (the Accent was purchased in October 2003). What is the "normal" expected lifetime of these parts? Should we be pursuing reimbursement from Hyundai (or the dealer) for the cost of the parts and labor for this repair? Could this be a manufacturer's defect?
Also keep in mind that Hyundai/Kia are cheep automobiles to begin with. One reason they are so inexpensive is because of the things you DO NOT SEE. The steel has a high pecent of poorly-recycled (to make it cheep) metals in it. The bodys rust out like a 1970 chevy and I am sure the brakes will too.
Since you saved so much $$ purchansing a Hyundai, you can use the cash you saved to get the brakes fixed. ;-)
Having a thick layer of rust around the perimitor of the rotors is a common occourance in the salt-belt. I usually just "turn" the rotors in -place with a steel bit to remove the rust. Installing HIGH QUALITY (ie..Bendix) rotors will elimintate that problem.
My 1970s and 1980s cars had brake rotors that froze up all the time. Even though I do all my own brake work, it was not worth it to install the same cheep OE equipment. I always shopped the autoparts stores for LIFETIME WARANTEE brake parts and installed those. Even if those parts did need to be replaced every 2-3 years, at least THEY coverd the cost of the parts.
I was going to wait for warmer weather to revisit the brakes and, as you've suggested consider replacing them with something of better quality. Needless to say, we're more than a little disappointed with the quality of this rather important part of the vehicle.
I think you easily got your money's worth out of the brakes and shouldn't feel the least bit short-changed on this one.
Do not forget that the biggest contributer to "frozen calipers" is contaminated brake fluid. All brake fluid should be changed every 2 years to reduce caliper freezups.
You may find with calipers, there is no "better quality" all you will find is "rebuilt originals".
When I mentioned better-quality, I was talking about the ROTORS which can vary widely in quality based on the material they are made of.
Your vehicle has seen at least 2 winters of salt-laden roads. That is plenty of salt to make your rotors start to rust.
As for brake pads, I run nothing but CERAMIC-based pads. The reduction in black dust on the wheels is wonderful thing 8-)
Well okay, my answer is still basically the same....you got salted roads, you got problems. It's a harsh environment. Maybe this particular car's design traps salt and moisture more than most, I don't know, but if you think about what brake calipers have to go through on slushy, salted roads, it's a wonder they survive two years at all.
So is this repair "normal"? No, I wouldn't say that. Can it happen now and then? Sure.
A common "ceramic based" pad is available thru NAPA as their "Ceramix" brand. (Made by Raybestos for NAPA) Virtually all friction-materal manufacturers have some "ceramic based" pad in their lineup. (Raybestos "QS" is their own Ceramic pad)
The performance difference for "ceramic based" pads include... very quiet(no squeels), Low dusting, and Long life. Some folks say that they are a bit more aggressive on rotors, but I have NEVER worn out a rotor. (mine always rust into oblivion.)
Here is an example:
http://members.aol.com/peebs4u2/powerslot_after_3winters.jpg
If you telephone any auto-parts store and ask for pads for your vehicle, they will offer you AT LEAST 3 "grades" of pads. The cheepest ones will make so much black dust that you will never be able to keep your wheels clean.
If you click on the links below you will see a comparison between several types of friction material.
http://www.nationalfleetparts.com/3types.htm
http://www.discpads.com/our_product_pads.asp
http://www.raybestos.com/usa/brakepads.htm
If you are suggesting that replacing REAR components make the STEERING WHEEL shake go away, then you are describing a near mechanical impossiblity. !?!? (I am assuming you DO NOT have 4-wheel steering)
As with all mechanical problems, one must identify all of the clues (symptoms) no matter how diverse they seem. I have over 30 years of troubleshooting complex mechanical systems and have learned that once the ROOT of the problem is found, all the clues make sense. (hindsight 8-)
With that said, are there any other symptoms besides shaking steering wheel that you can elaberate on.
Does it happen only when braking?
Does a bumpy road exagerate it?
Does the brake-pedal pulse?
Can your passengers feel it in their seat?
Is it more pronounced while turning to left or right?
If it is warping rotors, there are several things that can cause new brake rotors to warp prematurly;
1) Over-torquing lug nuts
2) Not seasoning the rotors
3) Dragging brake caliper
4) Cr@ppy rotors
The following webpage has a good description of how to season new rotors.
http://www.shotimes.com/brakes/part1.html
Any GOOD! mechanic would be able to do some hands-on testing of the front-end components to determine if you have dragging calipers, excessive runout, bearing endplay, loose tie-rods,...or any other issues that may be contributing to the situation.
So for example in one of my publications for a vehicle:
technical data, brakes
Front brake pad thickness is 14MM or .551. The wear limit is 7mm or .276.
On the front brake disc, thickness it is 22MM or .866. The wear limit is 19mm or .748
So if most folks eyes aren't glazed over by now, lets do the math.
So you have basically two wearing surfaces one rubbing off and providing friction(pads) and the other rubbing off and disipating heat (hence having to have a certain MASS to disipate in specification heat): rotor.
Brake pads can wear (14mm-7mm= or .551-.276) 7mm/.275
Brake rotors can wear (22mm-19mm= or .866-.748) 3mm /.118
The upshot is when the it is time to change brake pads, the rotors do not have enough "wearable" material to last the mileage the last set of pads probably did before it hits the wear limits (on the new set of pads).
So turning them (to true or zero run out them) CAN remove too much "wearable" material to leave enough buffer material before the new pads are KAPUT.
Friend's Porsche model's literally eat brake pads (and rotors) yet Porsche is known for having "bullet proof" pads and rotors. Brother in laws BMW 330i eats brake pads and rotors. Corvette Z06 which has been written up as having "less than Porsche brakes" have more than half the pads left with 68,000 miles (driven hard and put away wet, so to speak) rotors still have close to new thickness specifications.
I have VW Jetta TDI brakes which have developed a reputation for short lasting pads and rotors are on track at 49,000 miles to go to at least 100-150k miles fronts and 100-120k mile rears.
Also there are some auto stores that offer lifetime gurantees on very high quality brake pads (Performance Friction Z pads) to name one. All they require within wear specs, you bring back the old worn ones and they will give you a new set.
Some of the new exotic road-going/trackable Porsches (new GTs) use ceramic rotors that cost $8,500.....EACH! But then, for stopping at 210 mph or so, what's the problem with that?
Personally for the cost of new Porsche GT, I'm not going to quibble over a lousy $16,000 if I can stop ten feet sooner than a Corvette or Ferrari, especially if 5 of those 10 feet are occupied by a brick wall.
As you are no doubt aware, as one achieves perfection in anything, the last couple percentage points are astronomically expensive. It costs more than 10% to go from 200 mph to 220 mph, and a couple pounds off an already light mountain bike is going to be more than the cost per pound of the heavier bike.
Conversely, and getting back on topic a bit more, saving $5 by installing inferior brake rotors when you are building 500,000 of something is very very tempting for an automaker.
Are there defects or problems? Yes and No.
I don't think that remedy for my Toyota Landcruiser's would be applied to me unless it was demostrated in court. (the money I received for 4 sets of Toyota Landcruiser pads and brake rotors)
To me and I would hope to others, it is fairly logic that if one wants to track or drive hard that one should be prepared to change out pads and rotors on a fairly frequent basis compared to one who does not. Very simply, this is the real price for "flogging" the vehicle.
The concern, as folks have expressed it is when they do not tend to flog the vehicle BUT still have to change the rotors and brakes very frequently!?
I never had a car where it didn't eat brakes. Every car I ever owned. So obviously I'M THE PROBLEM!
small shop replaced front pads, ever since then high-pitched screaming from front right tire, beginning at 35-40 mph with no effect from braking...winds down with deceleration to a stop...have had relubing and clips checked, new set of brake pads, new rotor, still the sound continues, mechanic is at a loss and looking for advice from mechanics, so I'm doing my own research...HELP???
Dave
Apparently there's a design flaw in (at least) the 2000 SLK. The metal contacts for the brake lights are either the wrong type of metal, have the wrong type of rustproofing or both. After some time the contact between the brake light bulb and where that bulb is inserted into the light framework is burned away/corroded. This happens first to the brake lights which are either higher amperage or used more often. What happens is the brake light stops working and a warning light comes on on the dashboard. If you remove the bulb you find it intact. The Mercedes dealer will charge $800 each to replace the rear light assembly, but the issue can be solved for a little less than 5 cents plus labor if you can use a soldering iron. I felt I just had to share this with others.
Remove the rear brake light assembly by opening the plastic covers inside the trunk. The brake light assembly is attached with four metric nuts which are a little hard to get to, but the only fasteners for the whole assembly. There may be other components behind the plastic cover that make the brake assembly tough to get to, but they can be removed without removing screws/nuts.
Unplug the brake light assembly, remove the light bulb and examine the place where the brake light plugs into the back of the assembly. On either side where the light bulb holder contacts the assembly you will see a darkened/corroded area. This corrosion/lost metal are preventing the bulb from getting power. Scrape the corrosion away and put a layer of solder over the pitted metal so that the bulb will get good contact.
Replace the bulb and assembly. Plug the assembly back into the car and close the plastic panels. Spend the $1,600 (!!) you just saved on something nice. Send me an email saying how wonderful I am.
Hope this helps someone - I'm quite glad I figured it out and couldn't find it anywhere else.