2001 V70XC - Intermittent suction/burp Topic is solved

Post by **xHeart** » 21 Jan 2021, 09:05

Noticing faint suction/burp when coming out of driveway; where steering is turning close to full. The fluid level is near full. Inner and out tie rods, and boots were replaced more than a year ago, more here viewtopic.php?f=9&t=88332.

How to locate or diagnose? Would reading ECU over VIDA help?

Post by **darrylrobert** » 22 Jan 2021, 02:59

Do you mean the RPM drops when at full lock, thats because the pump is trying to push on the stop. do you get a high pitched whine at full lock?

Post by **xHeart** » 27 Mar 2021, 16:40

darrylrobert wrote: ↑22 Jan 2021, 02:59 Do you mean the RPM drops when at full lock, thats because the pump is trying to push on the stop. do you get a high pitched whine at full lock?

It appears less steering related, but when lifting foot off the brake pedal.

Post by **xHeart** » 28 Apr 2021, 11:39

Found this thread 2007 S60 Vacuum Boost Operation Issue to help isolate viewtopic.php?f=9&t=96910&p=571300

Post by **xHeart** » 28 Apr 2021, 13:57

AND this too viewtopic.php?f=9&t=92856

Post by **xHeart** » 29 Apr 2021, 15:02

Our 2001 V70XC is older, it does not have the vacuum pump shown in the DIY video. However, following explains the parts and its workings for me to explore it in my situation.

jimmy57 wrote: ↑05 Feb 2020, 23:09 ...one of the common reason a booster is replaced is that the regulator valve doesn't close the atmospheric vent.

When a pedal is pushed, and pushrod begins to move master cylinder, it shuts off vacuum and opens atmospheric vent.

The pedal being released acts to close the vent, which then connects vacuum back to the diaphragm. If the regulator valve (aka booster control valve) doesn't close the atmospheric vent, you will have a vacuum leak at the diaphragm, i.e. vent has failed to close.

Post by **xHeart** » 01 May 2021, 06:29

xHeart wrote: ↑29 Apr 2021, 15:02 Our 2001 V70XC is older, it does not have the vacuum pump shown in the DIY video. However, following explains the parts and its workings for me to explore it in my situation.

jimmy57 wrote: ↑05 Feb 2020, 23:09 ...one of the common reason a booster is replaced is that the regulator valve doesn't close the atmospheric vent.

When a pedal is pushed, and pushrod begins to move master cylinder, it shuts off vacuum and opens atmospheric vent.

The pedal being released acts to close the vent, which then connects vacuum back to the diaphragm. If the regulator valve (aka booster control valve) doesn't close the atmospheric vent, you will have a vacuum leak at the diaphragm, i.e. vent has failed to close.

Visualizing jimmy57's description...two diagrams from the Brake System - these are also on VIDA. Can I hook up MityVac to check vacuum?

Vacuum pump - is this the pump that runs (starts and stops) if there is a vacuum leak -- oragex video.

I had replaced the sensor item #7 at the booster a while ago - what does it sense, and reports over DTC?