Jetsfan68
NJ
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Joined: 02/27/2002
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OK here is my situation:
Put "NEW" Calipers, rotors, pads on front of 2001 F250 about 10 months ago- Bled system- etc-- Last week i had done some heavy braking with the trailer down some large hills- Really gave them a workout. Since then it seems when brakes heat up- I get some shudder in the brake pedal when braking- Took a look again- Pads and rotors look fine....didn't see anything unusual- Whats interesting is it does not seem to shudder when I first drive- As brakes heat up seems to get worse.... is it possible my rotors have become warped in such short time??
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Campfire Time
Wisconsin
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Joined: 07/20/2007
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Your rotors are not warped. They have pad material on them. Likely from getting them very hot, then stopping and holding them down for a period of time. Did you bed them properly? It makes a big difference in pad life. New pad bedding procedure
Chuck D.
“Adventure is just bad planning.” - Roald Amundsen
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Turtle n Peeps
California
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Joined: 06/23/2008
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Campfire Time is right on the money.
Bedding in new brakes is VERY important.
They "usually" will come back but it will take a very long time to do. I usually ruff up the rotor and sand the pad a bit and bed them in and all is good.
~ Too many freaks & not enough circuses ~
"Life is not tried ~ it is merely survived ~ if you're standing
outside the fire"
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BenK
SF BayArea
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Joined: 04/18/2002
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Rebed them
A lot depends on the brand/model/etc brake pads
I have some NAPA Ceramic and don't like them on my Odyssey mini van. Labeled
'high performance', which they are, but the binders out gas too easily for my
type of driving style.
Had it in for a SES (coils and needed a tune anyway) and my mechanic turned the
rotors because he felt the pulsations.
I normally just go out and rebed them.
Above posts that end up at the Stop Tech article is right one, but I disagree
with StopTech in that there is such a thing as warped rotors...just not as
common as most think and have them turned when all they need do is rebed them
-Ben Picture of my rig
1996 GMC SLT Suburban 3/4 ton K3500/7.4L/4:1/+150Kmiles orig owner...
1980 Chevy Silverado C10/long bed/"BUILT" 5.7L/3:73/1 ton helper springs/+329Kmiles, bought it from dad...
1998 Mazda B2500 (1/2 ton) pickup, 2nd owner...
Praise Dyno Brake equiped and all have "nose bleed" braking!
Previous trucks/offroaders: 40's Jeep restored in mid 60's / 69 DuneBuggy (approx +1K lb: VW pan/200hpCorvair: eng, cam, dual carb'w velocity stacks'n 18" runners, 4spd transaxle) made myself from ground up / 1970 Toyota FJ40 / 1973 K5 Blazer (2dr Tahoe, 1 ton axles front/rear, +255K miles when sold it)...
Sold the boat (looking for another): Trophy with twin 150's...
51 cylinders in household, what's yours?...
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zx9rt1
Heartland
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Joined: 11/27/2010
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I wonder if Ford Motor Company approves of the method? I really enjoyed the "smoke" and strong "burning" smell that may arrise after performing the bed-in procedure. I'm trying to picture this in my mind. Customer takes his 50k+ F-350 to the local dealer to have a brake job done. Customer waits in the lobby for his truck. A little time passes by, Mr Customer see's his truck being brought up on the service drive. Mr Customer see's smoke billowing out of the wheel wells. Mr Customer is horrified by what he see's. Service manager tells Mr Customer that is a normal condition after every brake job they do. Mr Customer now performs the "pee pee dance" right there on the spot. Yep, I'd pay good money to see that show.
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BenK
SF BayArea
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Joined: 04/18/2002
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If there is still visible smoke...then they have NOT been rebedded right.
Key is to keep rolling so that the out gases DO NOT bake on another high spot
By keep on rolling to cool down the friction material till it stops outgasing
as that will then have an even coating of friction material on the cast iron
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zx9rt1
Heartland
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O.k. I think I understand the process now. Procedure reduces material transfer to the rotor which in turn minimizes brake rotor thickness variation that cause brake pedal/steering wheel, and floor pan vibrations. Correct?
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BenK
SF BayArea
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Best braking is when there is an EVEN coating of the same friction material baked
onto the rotor/drum
During braking, hard/severe/etc, the friction material sacrifices itself turning
the energy into heat. During this, both the binders and the main ingredient in
the friction material scrubs/burns/etc off
The binders get hot enough to smoke (out gas) and this then further coats the
rotor/drum...to be scrubbed off during the next braking cycle.
But if you stop and the still outgasing friction material sits on a 'spot'...it
will bake on a higher spot that will be felt in the brake pedal. I've read
articles that says 0.0004" thickness differential can be felt in the brake pedal
Remember, there are or can be thousand of PSI pressing on the pads/shoes to rotor/drum
So 'felt' as a bump to raise the pedal (push back) and that since
it is higher it tries to stop 'better' on that spot to be felt as
more braking to then lesser braking when the thickness subsides to
repeat it again on the next round
So, once they get hot enough to outgas during rebedding, keep on rolling till they
cool enough to stop outgasing
Why I always do this on the freeway when there are no other cars/trucks out
there. Get up to some high speed (obey laws...) and nail the brakes several
times, but DO NOT stop and keep on rolling till they cool off.
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Campfire Time
Wisconsin
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Joined: 07/20/2007
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BenK wrote:Rebed them
Above posts that end up at the Stop Tech article is right one, but I disagree
with StopTech in that there is such a thing as warped rotors...just not as
common as most think and have them turned when all they need do is rebed them
I completely agree. Warped rotor occur more often from using an impact wrench without a torque stick. And even that doesn't happen all that often. The other cause of warped rotors I know of is bearing run out.
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dangerbird
Delanson, New York
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Joined: 09/04/2005
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Another thing to consider is letting your brakes sit wet after washing the vehicle. The rotors will get a good rust spot under the pads. When I wash my car or truck and will not be driving it for a while, I take it up the road a bit with a light touch of the brakes to make sure everything is dry before parking.
Carl
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