Please help stop the bouncing. - The 1947 - Present Chevrolet & GMC Truck Message Board Network

oj70chevy · 02-19-2007, 04:02 PM

I have a 93 GCM sierra. Every time I press the brakes to stop my front end starts to bouncing up and down. I know it is not the back because I can fell it in the steering wheel. And it does not happen when I tried to stop the E-Brake. I have put new tires, front end alignment, brakes, shocks, and had the rotors turned. If any one has any ideas please let me know.

Thank You
Ralph Vega

Russell · 02-19-2007, 04:34 PM

Usually thats a front disk brake problem... Make sure your calipers and rotors are good

oj70chevy · 02-20-2007, 12:13 PM

Quote:

Originally Posted by Russell

Usually thats a front disk brake problem... Make sure your calipers and rotors are good

Yha the calipers are fine I also had the rotos recut and new brakes installed.

pharcyde05 · 02-20-2007, 03:40 PM

toss the rotors dont waste the time of having them turned they worp the once you have them turned they are thinn and worp even faster
if you are set the the rotors arnt the problem then chack and see if you have front ABS and see if you have a problem with your module

19GMC63 · 02-20-2007, 11:10 PM

yep, measure the rotors with a dial indicator just to be sure

st1x10 · 02-20-2007, 11:44 PM

Have u tried unplugging the EBCM (electronic brake control module)?? Might try that, it is a problem with those that I have seen before.

oj70chevy · 02-21-2007, 11:46 AM

Quote:

Originally Posted by st1x10

Have u tried unplugging the EBCM (electronic brake control module)?? Might try that, it is a problem with those that I have seen before.

I am gessing I may have bad rotors. just wanted to ask, if the rotos are worped should my truck bounce or shake when driven? But disconnecting the EBCM would seem to be a free check before spending any money. Where is it and how do i unplug it? also is it safe to drive with it unpluged?

Thanks
Ralph

bobthecop · 02-21-2007, 11:50 AM

Warped rotors cause a vibration or pulsation when brakes are applied, warping comes from rotors being hot and then quick cooled, or overheating. I have also seen rotors continue causing the pulsation when turned off the car, find a shop that can turn the rotors on the vehicle, or replace them, sometimes the rotors are not flush against the hub, and turning them off the car makes them true to themselves, not that they are bolted to.

02-19-2007, 04:02 PM	#1
oj70chevy 250 V-6 Club Join Date: Feb 2005 Location: San antonio, TX. Posts: 898	Please help stop the bouncing. I have a 93 GCM sierra. Every time I press the brakes to stop my front end starts to bouncing up and down. I know it is not the back because I can fell it in the steering wheel. And it does not happen when I tried to stop the E-Brake. I have put new tires, front end alignment, brakes, shocks, and had the rotors turned. If any one has any ideas please let me know. Thank You Ralph Vega __________________ 1970 Chevy C/10 6 Cyl. 43k original miles all factory .http://67-72chevytrucks.com/vboard/s...d.php?t=197523 Never ask a stupid question unless you want a stupid answer .

02-19-2007, 04:34 PM	#2
Russell Professional Grade Join Date: May 2003 Location: Fort McMurray, Alberta Posts: 7,915	Re: Please help stop the bouncing. Usually thats a front disk brake problem... Make sure your calipers and rotors are good __________________ 1995 Chevrolet 2 Door Tahoe (6.6L LBZ Duramax / ZF6 / NP241 with 1 ton solid axle swap)

02-20-2007, 03:40 PM	#4
pharcyde05 Senior Member Join Date: Mar 2006 Location: modesto CA Posts: 239	Re: Please help stop the bouncing. toss the rotors dont waste the time of having them turned they worp the once you have them turned they are thinn and worp even faster if you are set the the rotors arnt the problem then chack and see if you have front ABS and see if you have a problem with your module __________________ http://www.cardomain.com/ride/2461088

02-20-2007, 11:10 PM	#5
19GMC63 Registered User Join Date: Nov 2006 Location: Nashville, TN Posts: 1,510	Re: Please help stop the bouncing. yep, measure the rotors with a dial indicator just to be sure

02-20-2007, 11:44 PM	#6
st1x10 Registered User Join Date: Feb 2006 Location: Oklahoma City Posts: 588	Re: Please help stop the bouncing. Have u tried unplugging the EBCM (electronic brake control module)?? Might try that, it is a problem with those that I have seen before. __________________ 1970 Chevy C10 "Under Construction" 2002 Chevy S10 V6

02-21-2007, 11:50 AM	#8
bobthecop Senior Member Join Date: Nov 2006 Location: Yukon Oklahoma Posts: 2,647	Re: Please help stop the bouncing. Warped rotors cause a vibration or pulsation when brakes are applied, warping comes from rotors being hot and then quick cooled, or overheating. I have also seen rotors continue causing the pulsation when turned off the car, find a shop that can turn the rotors on the vehicle, or replace them, sometimes the rotors are not flush against the hub, and turning them off the car makes them true to themselves, not that they are bolted to. __________________ Happiness is towing your "new" truck home. 1972 C-10 1982 GMC (parts truck??) 1969 c10 parts truck 1969 C-10 ( my sons) 1992 Silverado 4X4 (now the boys truck)(now mine again) 2002 Tarus (my wife loves that car)



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