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Snowman9000's avatar
Snowman9000
Explorer
Jun 11, 2017

Brake system noise

Chevy Express 4500 van chassis. This morning first thing, backing up to leave camp, when I applied the brakes, there was quite a growl. It varied in intensity. It persisted after we came to a stop. It sounded like a pump or bearing going bad. By the time I got down to the campground entrance, I had figured out it was to do with the brakes. Press on the pedal, get noise. Release the pedal, in a moment or two the noise would stop. Moving or not, so it's not the actual brakes or bearings.

By the time we got into town, no noise, can't make it happen again. Now we have driven all day, no more noise. Fluid level is good. MH has 20K miles or so.

ABS pump, I am thinking. What, why, etc.?? Is the pump driven electrically? If this doesn't re-occur, I'm driving it another 500-ish miles in the next couple of days, and then to the dealer.
  • Has it been a while since you last driven it? It could be surface rust developing on the disc as well and you have scrubbed it all off. So you won't get the issue until you develop more surface rust again.

    Also, if it's your ABS pump, you typically get some feedback on your pedal, like some sort of pulsating sensation below your foot. Did you have that?
  • It's not disc rust, because it was also happening with the trans in park, when I pressed the pedal. It has been driven over 4000 miles in the past month.

    It did not pulse like an ABS functioning. I am familiar with that feel. It growled like a bad pump or bearing. Even when in park, with the brake pedal pressed.
  • It is the hydraboost, powered by the power steering pump. After it warmed up, it calmed down.
  • I would have the brakes looked at but if the noise goes away after one or two stops it is just surface rust on the rotors. This drives my wife nuts and I had to switch out the pads on her 2012 200S within 2000 miles of owning it. If you go to a ceramic pad the noise goes away. The heavy metallic in the OEM pads are the issue.

    Don