pulsating brakes and noise(help me please!)

[duron]

Hello,


Some time ago, I had a problem with my brakes pulsating when coming to a stop around the 20mph area. The feeling was like someone pumping the brakes ever so slightly. I was told by my mechanic that my rotors my have been warped(spelling?)

I then once it was time to change out, had them change front pads to porterfield dustless(works great) as well as the front rotors which was as rotor they had in stock that had holes drilling into them. I also changed back rotors and pads, but with OEMs.

The first few days were fine exept for the fact that now and currently when slowing from say 55 once I get to about 40 I get a low tone noise that sounds like rough tire noise (not squeel) and that tone gets deeper as the car slows. That is one issue.

The next is after a few day of no pulsating, it returns. The guys check the rotors and inform me that after placing them on either a machine or putting some kind of tool to them that measures rotor(I am not a mehanic) depth or straightness. They tell me that my rotors are fine, but I may have something going on with ABS.

so, to recap:

1. noise at low rpm stopping(I think it is drilled rotors)
2. pulsating

Any ideas at all from you guys, as I would like to solve both issues at my 150K service coming up in a week or two.

I have '93 400e

Thanks,


Duron

[mark cummins]

Have You checked ALL four brake rotors for runout? What Brand Were the Rotors.?.Yes They can Warp..(NEW)
It can be done on the car! With The Proper tools. Sounds Like a out of round rotor..Inspect the Front end..Lower control arms/Ball Joints Etc
If It was a ABS Problem I Think You would have a Stored code and ABS light on

[duron]

Thanks Mark, I will have them check it out as I am up for the 150K service. I don't know the brand of rotors they installed, but once the installation was done, I did not have the problem until a few days or so later. I was told after the fact that I should never rinse the rims after a ride as everything would be hot including the rotors and that this may cause the warping.

What do you do? What if it begins to rain on a hot day? Does that warp the rotors?

What brand do you guys recommend that would be least likely to cause this problem?

Do you like drilled or no drilled and could the drilled ones cause the noise that I have braking at speeds of 55mph?


Duron

[mark cummins]

[QUOTE]Originally posted by duron
[B]Thanks Mark, I will have them check it out as I am up for the 150K service. I don't know the brand of rotors they installed, but once the installation was done, I did not have the problem until a few days or so later. I was told after the fact that I should never rinse the rims after a ride as everything would be hot including the rotors and that this may cause the warping.

You just Answered your own Question...If You Hosed them off when the brakes are Hot ..YES you WILL Warp them..theres The Problem...Cold Water and Hot Rotors Do Not Mix !
Hope they can Machine the rotors to save them...




Do you like drilled or no drilled and could the drilled ones cause the noise that I have braking at speeds of 55mph?

Yes I Have The Crossdrilled rotors on my cars Since the 80s Including Several of My Porsches without any problems..I Have The Rotors Treated ala cold Dip That Helps them last up to Three times longer..Porterfield did My rotors
And Yes You can hear Some Noise from them ..The Air Passing Through them..Hissing..No Big Deal to me..Others Say The Cross drilled rotors warp rotors...Porsche has had Drilled rotors since 1978 on the 930 With NO problems..And The Late Mercedes Are Drilled ...left pattern only..Without any problems..go figure