Strange random brake vibration issue, need ideas. - The 1947 - Present Chevrolet & GMC Truck Message Board Network

foamypirate · 12-15-2010, 06:41 PM

Hey guys,

I've got a strange brake problem with my 87' 1/2 ton. Every once and a while, when I get on the brakes, they will shudder badly. Now, I'm not talking warped rotor shudder, I'm talking, "HOLY CRAP MY TRUCK IS GOING TO RATTLE TO PIECES AND MY FILLINGS ARE FALLING OUT" shudder. The entire truck vibrates very rapidly and violently. It typically happens within the first 3 stops from cold. It will only do this one time, every stop after it does it is fine, nice and smooth, no vibration. It is also typically at low speeds (below 20mph). The intensity of the vibration makes it nearly impossible to determine if it's front/rear or left/right. It's almost like it's maybe locking up a wheel and skidding along.

The part that is making this really hard to trouble shoot, is the irregularity of it. It's only done it maybe 6-8 times in the last 9 months, but it's getting more frequent as of late.

Anyone have any ideas? If you need any more information, I'd be glad to offer it up.

foamypirate · 12-16-2010, 07:20 PM

Beuller, bueller?

Doug_J · 12-16-2010, 08:06 PM

maybe take your callipers off and see if thirs any rust on the piston maybe causing it to stick, if your wheel is locking up?

James McClure · 12-17-2010, 09:19 AM

Old Chevy mechanic here. The vibration you discribe, IE, vibration mostly when cold and within the first few minutes of operation and then no problems the rest of the drive. This is comming from the rear brakes and is mostly associated with a very light coating of rust that developes on the drums over night. Can also be caused by rear end grease on the linings. We ( Chevrolet mechanics ) never did come up with a solid correction that would eliminate this problem, but we did come up with some corrections that would mitigate it to some degree. I do this with my truck everytime I take it out. While backing up, apply the brakes as you move but keep moving. Go 20 or so feet backwards draging the brake. When you go to move forwards again drag the brake a little. This stops my vibration. Also make sure to keep brakes adjusted right up. jim

foamypirate · 12-17-2010, 07:11 PM

Thanks for the input! I'll try to remember to do that from here on out. Glad to know my truck isn't going to fall apart! :P

12-15-2010, 06:41 PM	#1
foamypirate Registered User Join Date: Apr 2009 Location: Pflugerville, TX Posts: 594	Strange random brake vibration issue, need ideas. Hey guys, I've got a strange brake problem with my 87' 1/2 ton. Every once and a while, when I get on the brakes, they will shudder badly. Now, I'm not talking warped rotor shudder, I'm talking, "HOLY CRAP MY TRUCK IS GOING TO RATTLE TO PIECES AND MY FILLINGS ARE FALLING OUT" shudder. The entire truck vibrates very rapidly and violently. It typically happens within the first 3 stops from cold. It will only do this one time, every stop after it does it is fine, nice and smooth, no vibration. It is also typically at low speeds (below 20mph). The intensity of the vibration makes it nearly impossible to determine if it's front/rear or left/right. It's almost like it's maybe locking up a wheel and skidding along. The part that is making this really hard to trouble shoot, is the irregularity of it. It's only done it maybe 6-8 times in the last 9 months, but it's getting more frequent as of late. Anyone have any ideas? If you need any more information, I'd be glad to offer it up. Last edited by foamypirate; 12-15-2010 at 06:43 PM.

12-16-2010, 07:20 PM	#2
foamypirate Registered User Join Date: Apr 2009 Location: Pflugerville, TX Posts: 594	Re: Strange random brake vibration issue, need ideas. Beuller, bueller?

12-16-2010, 08:06 PM	#3
Doug_J Registered User Join Date: Apr 2009 Location: Moore,OK Posts: 178	Re: Strange random brake vibration issue, need ideas. maybe take your callipers off and see if thirs any rust on the piston maybe causing it to stick, if your wheel is locking up?

12-17-2010, 09:19 AM	#4
James McClure One shot, one kill. Join Date: Dec 2007 Location: Saratoga Springs NY Posts: 859	Re: Strange random brake vibration issue, need ideas. Old Chevy mechanic here. The vibration you discribe, IE, vibration mostly when cold and within the first few minutes of operation and then no problems the rest of the drive. This is comming from the rear brakes and is mostly associated with a very light coating of rust that developes on the drums over night. Can also be caused by rear end grease on the linings. We ( Chevrolet mechanics ) never did come up with a solid correction that would eliminate this problem, but we did come up with some corrections that would mitigate it to some degree. I do this with my truck everytime I take it out. While backing up, apply the brakes as you move but keep moving. Go 20 or so feet backwards draging the brake. When you go to move forwards again drag the brake a little. This stops my vibration. Also make sure to keep brakes adjusted right up. jim __________________ 1984 K20 350M engine with 465,000 miles. Well, it's finally done!! Almost 2 years of work, but it was really worth the effort. Little stuff left to do is mount winch, wet sand & buff out and build belly pan\running boards. Body work takes lots and LOTS of beer!!!! God, Guts and Guns made America and God, Guts and Guns will preserve it! The worst thing you could do is get into my sights, but that don't matter, you'll never know it, cause you'll never hear the shotJim or Paladin whichever you choose.

12-17-2010, 07:11 PM	#5
foamypirate Registered User Join Date: Apr 2009 Location: Pflugerville, TX Posts: 594	Re: Strange random brake vibration issue, need ideas. Thanks for the input! I'll try to remember to do that from here on out. Glad to know my truck isn't going to fall apart! :P



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