Help! Help ! Harsh sound from back of car after brake job

[Eve]

Ok, I made a mistake and took my 1988 Vette to a local national brake place because I was in a hurry. I had them replace all the fluid, complete brake job and they even replaced the "Bosch" antilock unit. Now, the brakes work great - the car will stop on a dime. But, when I first crank the car and either go forward or reverse, I get a noise from the rear end that sounds to me like high pressure liquid flowing. It only last maybe 3 seconds, then you don't hear it again until the car is cut off and first moved again. So to shorten the story, I finally took my car to the factory trained Corvette shop in town. He pressure bleed the brakes, checked all the wheels, reinstalled the old antilock unit (then replaced the newer unit) - still the noise. This noise was never present before the first brake job & the factory trained guy cannot figure out the noise. Can anyone solve the puzzle? :W

 

[ecss]

The ABS unit does a self test every time the ignition is cycled and the car reaches a speed above I believe 3 mph.

When you first turn the ignition On you should see the ABS indicator light in the Driver Info Center come on then go out. This indicates the ABS has passed a static self test. As the vehicle moves another test is done. The noise you hear is the ABS pump. It's located in the rear driver side storage compartment. If either the static self test or the active self test fails, the ABS light will come on solid and the ABS function is disabled.

If you were to slightly press on the brake pedal when the active test is taking place you will feel the brake pedal pulse slightly which is normal. It appears you don't have a problem.

My drive way has a steep incline. When I back up I have my foot on the brake pedal and can always feel the brake pedal pulsing and the ABS pump makes a whirling sound. This is normal operation.

 

[Eve]

Thanks for the feed-back! After I posted, I saw a section that has Chevy Service Bulletins. One covers this
noise! Again, thanks so much