2007 S60 Brake Vacuum Pump duty cycle

sskerry · Post by **sskerry** » 09 Nov 2016, 21:53

I have tried googling this issue, and have found many problems relating to it, however not mine specifically.

The issue is, the pump is running ALL THE TIME. Please see this youtube video to see what im talking about: https://www.youtube.com/watch?v=bndtqskTfqY

My brakes work perfectly, I'm wondering where and how to start diagnosing this.

sskerry · Post by **sskerry** » 09 Nov 2016, 22:02

Update: I found the valve right ontop of the engine compartment above the pump, I disconnected and cleaned the electrical connector and suddenly it seems to be working properly. I would still appreciate any insight, but at the moment it seems to be working.

Cookie-the-Swede · Post by **Cookie-the-Swede** » 10 Nov 2016, 07:32

Mine did the same thing, although it wasn't running ALL of the time. It ran for about 4 seconds EVERY time that I either pushed in or let off the brake pedal. It would be silent when the pedal was pushed and held down or let off of.
I replaced the pump, hoses, and booster switch with no improvement. Then I simply disconnected the plug on the top of the booster switch... and now the pump doesn't run at all!
I have noticed no difference at all in braking power or feel. So I just left it disconnected.

Post by **chrism** » 10 Nov 2016, 07:43

The purpose of the pump is so that you still have vacuum assisted brakes even if the engine were to die (assuming the key is still on). Just another one of those safety features of questionable necessity. When my pump was running overtime, I found it to be caused by a leaking brake booster. Temporarily clamping off the hose to the booster will tell you if that's the case with yours.

Post by **vtl** » 10 Nov 2016, 08:32

Cookie-the-Swede wrote:Mine did the same thing, although it wasn't running ALL of the time. It ran for about 4 seconds EVERY time that I either pushed in or let off the brake pedal. It would be silent when the pedal was pushed and held down or let off of.

Works as designed - dual VVT turbo engines don't have much vacuum at idle and don't have any vacuum under boost, so the brake needs vacuum assist. You WILL feel degraded brake performance when you try to brake hard in a series.

Cookie-the-Swede · Post by **Cookie-the-Swede** » 10 Nov 2016, 10:30

vtl wrote:
Cookie-the-Swede wrote:Mine did the same thing, although it wasn't running ALL of the time. It ran for about 4 seconds EVERY time that I either pushed in or let off the brake pedal. It would be silent when the pedal was pushed and held down or let off of.
Works as designed - dual VVT turbo engines don't have much vacuum at idle and don't have any vacuum under boost, so the brake needs vacuum assist. You WILL feel degraded brake performance when you try to brake hard in a series.

Thanks for that.

sskerry · Post by **sskerry** » 11 Nov 2016, 15:36

It seems to be doing it on and off now, I can make it stop by pumping the brakes several times to the floor, then the pump starts to act normal. Im leaning towards replacing the the pressure switch as I have read it is prone to failure. I dont think its a leaky booster since it does behave correctly most of the time, but its like the switch in the valve gets stuck to the on position somehow. I dont feel safe disconnecting it as this is my wifes car and I dont want to put her into any kind of situation where she will need the assist and not have it... Im worried though until i get it fixed that the pump running for extended periods of time is going to burn it out or cause it to fail prematurely.

Post by **vtl** » 11 Nov 2016, 16:25

Yeah, that's switch. Mine was doing same before it failed completely.