99 Taurus brakes pulsate

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Can anyone guide me in a direction that I can look at for my Taurus. I have replaced the brakes with new rotors and ceramic pads, I have the matching set, that was my first mistake. I actually went to ceramic pads on my last brake change, the car was pulsating when the brakes were applied so I decided to change the pads again. The car still pulsates when the brakes are applied, just wondering if anyone could help me.
Thanks

posted by  dvdb726

The first thread should always be in the introduce yourself section....however, not much is happening at the moment and I'm climbing the walls lol...so I'll help you out, that's not to say you shouldn't introduce yourself though.

I'm a bit confused by your post to be honest, first you say...

And then you say...So, are you saying you changed both the discs and the pads...or just the pads? :thumbs:

posted by  Cliffy

I replaced both the rotors and the pads 18 months ago, the car has been pusalting again so I decided to see if replacing the pads would help. So I did that this past Saturday but the car continues to pulsate.

posted by  dvdb726

Ok...now I understand....I'm not bored any more, how's the intro coming along? :ticking:

posted by  Cliffy

LMAO with Cliffy...not bored anymore?? LMAO :hi: :hi:

DVD: your problem is very simple. Pads will not make your brakes pulsate. The wrong ones could speed up the process of the rotors warping, but they wont be the cause of the pulsing, the rotors will. You simply have warped the rotors again. You might need to explore the pads as a cause for the rotors warping again. Pads can and will do it. Some are softer than others and can perpetuate the rotors from staying true. Good luck. How's the intro coming along?

posted by  cmeseadoin

My secret...if a tad inacurate Mod powers told me that he started an Intro...but now he's off line :ohcrap:

posted by  Cliffy

:ohcrap:

posted by  cmeseadoin

Does the tarus have ABS and if so, is the ABS light on? If not, these boys are on target about warped rotors.

posted by  tbaxleyjr

there could be an abs control unit fault

posted by  cinqyg

bingo - Odds are greater the problem is a warped rotor like you said but wanted to make sure the ABS wasn't throwing codes indicating other issues.

posted by  tbaxleyjr

There is no such thing as warped rotors. What you probably have are scuffed rotors with high and low spots. This is generally caused by the gas given off by the pads causing uneven pad contact as they chatter. Front wheel drive cars generally require soft pads to prevent the very problem you are talking about and to give maximum grip.

Unfortuantely the hemp pads aren't as good as asbestos and metal impregnated pads are also unsuitable for fwd vehicles.

posted by  Wally

All manufacturers have specifications for run-out (high spots) and parallellism (warpage) for their cars brake rotors. The latter is usually caused by differential stresses which are set up by a sudden cooling such as driving through water or other issues.

Semi metallics have been used as OEM on Front wheel drive cars for several years.

posted by  tbaxleyjr

gassing went out when aspestos was banned

posted by  cinqyg

Wally ole mate, I hate to call a spade a spade but if you are planning to come into this car forum and tell people there is no such thing as warped rotors and you might as well shoot yourself now!

What in the HELL are you talking about...no such thing as warped rotors??? I don't know what country or better yet, planet you live on....but where I live, warped rotors are COMMON on many vehicles and the condition is caused my inferior parts quality perpetuated by high levels of heat and the inability to disapate that heat in a effiencient and expedient manner.

You said the following which makes ZERO sense: "This is generally caused by the gas given off by the pads causing uneven pad contact as they chatter." WHAT? The fact of the matter Wally is that when youi brake, a thin layer of gas DOES develop between the pads and the rotors. The part about uneven pad contact as they chatter, what does that mean? If the pads are new and so are the rotors there is NOTHING uneven about ANYTHING. You need to seriously check your sources of technical car data before you come into a technical forum like this and mis-inform our members. I cannot believe someone other than myself has not called you out on this yet.

Let me ask you this....If there is no such thing as warped rotors (being defined as a rotor with excessive latteral runout) then why in the hell will "warped rotors" create a shuttering in the steering when the brakes are applied? HMM, let me guess.....could it be that by the rotors having that excessive runout, the pads are actually forced back and forth in a sideways motion causing the calliper piston(s) to move in and out, thus creating a brake pedal pulsation???? WHY YES, I think it could!!!!

Take your "scuffed rotors with high and low spots" theory to someone that might not have a clue and sell it to them, you are full of shit.

In response to the other posting about a problem with the ABS system if equipped, yes that could def. be a consideration as well. I assumed that if the ABS light was on, it would be stated but I KNOW I should not have assumed that. I would put dollars to doughnuts on the warped rotors being the culprit. PAY ZERO attention to wally and his ROCKET SCIENTIST conclusions about NO such thing as warped rotors. If you believe that shit, I have some beachfront property in Arizona for sale at 2 dollars an acre.

posted by  cmeseadoin

I'm with you on this one cmeseetcetc....I was concerned to read that Wally doesn't think trhere's such a thing as warped discs....esprcially given that he's a Mechanic!...(at least I think that's what he said he was lol...oh....and please ignor me when I keep saying 'Disc'...it's a Brit thing...I'm patriotic!)

posted by  Cliffy

I was setting the stage to call Wally's hand. In my mind, warped rotors are an issue or the factory would not publish the specs they do.

posted by  tbaxleyjr

You know one of the things that really irks me is the likes of the post made by cmeseadoin. I give you real information and you resort to insults because it doesn't gel with internet and hillbilly myths and probably some previous post where it was agreed warped rotors exist because you decided they do.

Let me tell you once again, rotors don't warp its "A MYTH". What is considered a warp is actually disc thickness variation (DTV) which generally occurs from off brake wear. The rotor is continuously being grazed by the pad, resulting in a thinning patch and brake shudder. Organic pads are notorious for this condition and particularly noticeable on low end and middle of the range cars

Hot brakes will also leave residue on the rotor that can cause shudder until the rotor gets hot again and it is sheared of by the pad or evaporates.

Now instead of getting on your high horse, go and consult with an engineer from a brake manufacturer and then be just as quick to post a retraction.

I don't mind rebuttals, by come on guys open your minds and you might actually learn something instead of stymying participation.

PS how about you publish your engineering qualifications and experience and I'll let you know my body volume that is sic. "full of shit".

posted by  Wally

Well, I was taught that discs warped...and I'm sticking with that....feel free to disagree though, no hard feelings...BTW, you just KNOW that cmesdoin is gonna flame you bad :laughing: :rock:

posted by  Cliffy

As "all" manufacturers publish "warpage" please give me a site where I view this specification and the word warpage. I am genuinely interested.

posted by  Wally

Yeah we were all taught that and I'm sure mechanics made a lot of money too.

I know a bloke at Cosworth there in England you can talk to if I haven't spurred you into doing some investigation. Actually forget that I have another bloke in mind who actually does testing and development for General Motors brakes who might give me a spiel to post. And guess what it will say :mrgreen:

Yes I know I will get a response from an over inflated ego, but let him bring it on. :wink2:

posted by  Wally

The cars factory service manual

calls for a run-out limit - 0.003 in and thickness variation of 0.00035 in for my Crown Vic.

You won't find "warpage" defined as an engineering term in an engineering text - Technically, what happens is sudden changes in temperature induce thermal stresses in the material due to localized expansion and contraction. The rotor deforms to relieve itself of those stresses creating the high spots on part of the rotor and causing excessive run-out and thickness variation. I can give references to several college level machine design texts and materials texts (some of which I studied while earning a mechanical engineering degree) which go into this in more detail.
Causes - The trigger can be sometimes pad related as it overheats the rotor or I have "warped" one by driving through a puddle of water after a hard stop. Crappy rotor design (in adequate cooling slot provisions, inadequate material for heat dissipation, rotor undersized for braking loads) contributes

Most car mechanics and car enthusiasts use warpage as any run-out condition or thickness variation which causes the rotor to pulsate. reason - If it is not parallell, it is warped in mechanics slang. The same goes for plate work, structrual steel, etc. A good mechanic understands this stuff due to their experieice and I as an engineer understand. The average customer (a banker, lawyer, teacher, etc) could care less about the cause - they just don't want the brakes to vibrate whan stopping the car.

posted by  tbaxleyjr

Wally,

You go ahead think of it how you think of it, the rest of us will think of it as "warpage." You don't have to be a rocket scientist nor an engineer to understand that when you take metal (ie...rotors) and heat them to an extreme temperature then super cool them as tbax states with water or whatever else, you will "warp" them. Or just super heating them by excessive brake usage.

Since you would love to discuss the engineering aspects of this matter...I am going to reduce all of what you have stated to basics. If you call the reason for brake pedal pulsation DTV (disk thickness variation) Wally, what in the HELL does that essentially equate to????? HMM gee, if a circumferential surface that is machined to certain specifications actually has areas that become "higher and lower" than others, what is that REALLY called? Could it be warped? The only way that a brake pedal will pulsate is if the rotor has runout laterally causing the piston(s) to move inward and out of their bores within the calliper. The only way a rotor will be in this condition is if it in a state of DTV, COMMONLY called WARPAGE. I totally understand where you are coming from with your high level explainations however there IS a such thing as warpage.

Keep in mind that most people in here care LESS to read your high level engineering and scientific attempts to explain a brake pulsation theory. Most can't even understand the simple thing we try to help them with. The reason that I originally flamed you big time was due to the fact that you typed a posting and basically all you stated what that there was no such thing as warpage. That is not correct. Any mechanic that has any time in the shop knows otherwise. I agree with you on the rotor glazing and the gaseous buildup that can and does occur. DTV does equate directly to a warpage effect and that is why oftentimes drivers report brake pedal pulsations.

posted by  cmeseadoin

Cliffy, were you drunk when you typed this one or where you just feeling like SLANDERING my login name? :laughing: :laughing: If I did not know you better I'd be :cussing: :orglaugh: :orglaugh:

posted by  cmeseadoin

Cliffy, were you drunk when you typed this one or were you just feeling like SLANDERING my login name? :laughing: :laughing: If I did not know you better I'd be :cussing: :orglaugh: :orglaugh:

posted by  cmeseadoin

Does everyone understand why brake rotors develop high spots, go out of parallel or warp?

If so, I think we've seen enough theory without holding an engineering class to last the average reader a long time.

posted by  tbaxleyjr

Sorry to reply to this tbaxle, I just have to reply to cmes....I was not drunk mate....I just cant remember your name lol, and I cant be bothered to memorise it :ohcrap:

posted by  Cliffy

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