My 05 s60 2.5T is recently out of warranty and have had my first problem with the car. When the car sits overnight or many hours during the day the vacuum assist on the brakes doesn't seem to work. After about 30 seconds no problem. Before I entertain the idea that the booster needs to be replaced, someone here mentioned the check valve. Problem is is that the check valves available on the web don't look like the one I see on my car. Just to clarify, where is the check valve located? Is on on the actual booster or is in somehwere else? It looks like there's a valve behind the front lights that goes to the intake and to the hose connected to the booster, but there's also a hose going down to a silver canister and an electrical connector on top.

Any advice on this would be appreciated.

Erik Larson
'05 S60 2.5T
'07 XC70 2.5T

 

There are auxillary vacuum pumps, the silver thing you are talking about i believe, controlled by that switch or valve behind the lights, on the airbox it clips on. They usually fail, the switch part; if you can access the connector to the pump and put power to it to check, that would help.

 

Replacing the switch seems like an easy fix. I can't seem to find that part anywhere on the various parts web sites. Any ideas what it's called or where I can get it? I guess I could always go to the dealer but would rather find it myself.
Thanks.

 

I too am having the same problem with my 2005 AWD s60. I am still trying to decide where this is. I am also now getting a check engine light on and the guy from Advance says that it looks like it could be the evap check valve? could this produce the problem we are getting and where are these check valves and switches. Can we see a picture anywhere? Any help will do I have been trying to figure out this brake problem for months. Thanks in advance for the quick answers.

 

Same boat, what is this part called/number... web searching has not yielded much... and I would like to get this fixed, damn scary everytime it happens.

 

Vacuum pump
31201707

Switch
31265825



For different motors and such are different part #'s contact dealer.

 

I'm going to start with the switch. I found it here and am going to order it right now. I'll let you know what happens.

Erik

http://www.rmeuropean.com/Part-Numbe...N_C271A50.aspx

 

That looks like the one.

 

Okay, I replaced the switch and unfortunately it made no difference. I still was without vacuum assist while I was backing out of my garage in down the driveway. I guess I'll check on the pump next. If anyone else has figured this out, let me know.
Thanks.

 

Has anyone found out what makes this occur? Could it be a Check Valve and where is it located? Thanks for anyones help in advance.

 

So this is a prevalent problem for these cars. There should be a recall on this prob. cuz it's an accident hazard. If a lot of people would file a complaint with the US NHTS agency (Nat'l Highway Traffic Safety -I hope I got it right) then it will investigated and could cause a recall. I'll start my complaint with the agency and hope u guys will follow suite. I checked my check valve (black wye valve connected near the intake manifold) and it was functioning properly. Anybody who finds a solution to this prob. pls post here asap.

 

Thanks I'll do this!

 

Anyone find out what causes this?

Thanks

 

I replaced something called the "brake booster switch" that sits behind the headlights on driver side and is connected with the vacuum hose to the booster. It made no difference. The good news is that my problem with this hasn't gotten worse. If I would wait 30 seconds after startup, it's fine. It seems to be only higher rpms. Also, when the weather cools it doesn't happen at all. Here in Chicago that's 3/4 of the year.

I still have a hunch it's the actual booster starting to go bad. It's a known problem on these cars. If I had money I would go ahead and replace it but I don't so I'll wait.
Erik

 

I had a similar issues and replaced Postion Sensor. Its located on The break booster .Looks like this eEuroparts - Postion Sensor - # 31261486. Does your Cruise control work ?? Also any Hiss or loss of air sound coming from Break pedal ??

 

Still have the same problem after all this time. Just thought I would check back in.
Thanks

 

How do I find the answers to my post?

 

Russell, I guess nobody found the solution to this problem or for those who did - never came back to share their findings. I too had this problem on my 03 S60 T5. I replaced Cam &crank PS, speed sensor due to multiple DTCs but none related to ABS. The brake problem went away just like that. Never experienced same prob for a year now. This prob was also raised over at MVS and nobody came up w/ a solution.

 

My car still has the brake problem. Im so used to just waiting 30 seconds now but I would stil like it fixed. My car sometimes fires when starting then quits immediately. Then it starts right up. Some people on this forum have suggested the cam position sensor. Is it possible tha if I replace this it could fix these 2 problems? That would be great but I'm not holding my breath. Any thoughts? Is it simple to replace?
Erik

 

Larpio, inspect the check valve connected to a hose coming from booster to manifold.