Hydraboost Brake System

dhunter360 · May 6, 2005

Hello All, I’m new to this so bear with me. I have a 1997 GMC 3500 1 Ton with the Vortec 454. It has drum brakes rear, disc front with the hydraulic hydraboost.

OK here is my problem, when I’m moving slow,30mph down, I have a chatter that appears to be in the brake system, It sounds terrible until you gently touch the brake peddle. As soon as you touch the brake peddle it goes away. It has done this since I acquired the truck. I have reworked the rear brakes “had rear seal leak”, installed a new hydraboost “ it had minor leak”, front brakes look good but problem persist. I have isolated it to the brake system but haven’t been able to determine the source; I’m new to the hydraboost system. Any and all help will be greatly appreciated.

dhunter360 · May 6, 2005

Hello All, I’m new to this so bear with me. I have a 1997 GMC 3500 1 Ton with the Vortec 454. It has drum brakes rear, disc front with the hydraulic hydraboost.
OK here is my problem, when I’m moving slow,30mph down, I have a chatter that appears to be in the brake system, It sounds terrible until you gently touch the brake peddle. As soon as you touch the brake peddle it goes away. It has done this since I acquired the truck. I have reworked the rear brakes “had rear seal leak”, installed a new hydraboost “ it had minor leak”, front brakes look good but problem persist. I have isolated it to the brake system but haven’t been able to determine the source; I’m new to the hydraboost system. Any and all help will be greatly appreciated.

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HELP!!!

byronlj · May 6, 2005

I had the same symptons with my work, truck 89 gmc. I pulled all the wheels couldn't find anything. My son was changing the oil and lubing it and found one of the caliper bolts just sitting loose on the driver side front.

Dave

mmmikkke · May 7, 2005

...It sounds terrible until you gently touch the brake peddle...

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Did you replace the rear brake linings? Sounds like maybe they're sticky maybe. Could hit them with CRC Brakekleen, or similar product.

Test: Apply the parking brake lightly to see if that also stops the chatter. If so, you could consider the problem at the rear brakes only.

jake111 · May 7, 2005

Sounds to me like front disc brakes. There are often various backing plates on the pads and/or other spring clips to keep the pads from moving around (chattering) when there isn't any pressure on them (and they just float). Just touch the brakes lightly and the pads snug up and stop making noise. With a little (very little) wobble in the rotor and the pads get knocked around a little.

I did brakes on my old Dodge van and one side makes noise sometimes. I (try to, and mostly) ignore it. Sounds much worse than it is. You can try a sticky disc quieting spray on the pad backing plates (not on the pad!!). Sometimes the only solution is new rotors and good quality pads that come with all the backing plates and/or clips, and sometimes it means getting genuine oem parts from a dealer.

silverado3500 · May 8, 2005

Sounds to me like front disc brakes. There are often various backing plates on the pads and/or other spring clips to keep the pads from moving around (chattering) when there isn't any pressure on them (and they just float). Just touch the brakes lightly and the pads snug up and stop making noise. With a little (very little) wobble in the rotor and the pads get knocked around a little.

I did brakes on my old Dodge van and one side makes noise sometimes. I (try to, and mostly) ignore it. Sounds much worse than it is. You can try a sticky disc quieting spray on the pad backing plates (not on the pad!!). Sometimes the only solution is new rotors and good quality pads that come with all the backing plates and/or clips, and sometimes it means getting genuine oem parts from a dealer.

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I would also suggest checking your caliper slide bolts to make sure they aren't stuck, also check your wheel bearings. Even a slight amount of play there, could cause the noise.

Hope thats helpful

dhunter360 · May 8, 2005

Thanks I will start lookingas directed. It does appear to come from the front, and now you have given me somthing to check Thanks again.

Sounds to me like front disc brakes. There are often various backing plates on the pads and/or other spring clips to keep the pads from moving around (chattering) when there isn't any pressure on them (and they just float). Just touch the brakes lightly and the pads snug up and stop making noise. With a little (very little) wobble in the rotor and the pads get knocked around a little.

I did brakes on my old Dodge van and one side makes noise sometimes. I (try to, and mostly) ignore it. Sounds much worse than it is. You can try a sticky disc quieting spray on the pad backing plates (not on the pad!!). Sometimes the only solution is new rotors and good quality pads that come with all the backing plates and/or clips, and sometimes it means getting genuine oem parts from a dealer.

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I would also suggest checking your caliper slide bolts to make sure they aren't stuck, also check your wheel bearings. Even a slight amount of play there, could cause the noise.

Hope thats helpful

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