Pump noise

[Myron]

While traveling downhill in my 2005 Sightseer there is a large whining pump noise, perhaps the parking brake pump, after some hard braking. It is like something is getting pressurized. It has never done that on flat ground. The brakes work as does the parking brake. I pulled off to let them cool after some serious downhill work. Everything seemed fine but that noise is worrysome. It was very hot so could it be possible that one of the fans is running ? It really didn't sound like a fan.

[Myron]

While traveling downhill in my 2005 Sightseer there is a large whining pump noise, perhaps the parking brake pump, after some hard braking. It is like something is getting pressurized. It has never done that on flat ground. The brakes work as does the parking brake. I pulled off to let them cool after some serious downhill work. Everything seemed fine but that noise is worrysome. It was very hot so could it be possible that one of the fans is running ? It really didn't sound like a fan.

[edgray]

MYRON: it would be oh so helpful if you would give us chassis info to work with. Now we can only assume you have a gas chassis, and going downhill you probably don't have your foot on the gas pedal. IF this assumption is true, then your engine isn't making a lot of vaccum to assist the brakes, and therefore the electric motor powered pump is running to help power your brakes. It probably means nothing is wrong and the electric back up system is doing it's job. However, you may want to check for a leak in your vaccum system.