[rcy]

Maybe I suck at entering the proper search parameters, but I could only find a few threads regarding this. It was -20c the other night and I suffered through this for the first time. Luckily I was in a parking lot at low speed. The brakes still worked, but there was no power assist, and thus, a very firm push on the pedal was needed to stop the car. After the first stop, the problem was gone, only to return after the car was parked overnight again.

Anyway, the thread I found suggested WD40 into the vacuum line to displace the moisture that is freezing the check valve (it seems to me like I might have two check valves in the line, but I was doing this in the dark - can anyone confirm? One seemed to be about halfway down the line and the other was closer to the end of the hose nearer the engine, but this just might have been the metal nipple the hose goes over) I did the WD40, but the weather has become warmer so I don't know if it helped or not.

Finally, is there a recall or TSB for this? Seems to be a bit of a dangerous thing to me and wondering if gov't has or should mandate some sort of recall. Has Subaru redesigned the booster hose/check valve to deal with this? Is the check valve essential, or could I run a normal hose without the check valve?

Thanks.

 

[wilsonhp]

This happened to me again a few days ago, during that -20 cold snap.

I repeated the WD40 treatment, but as you say, it has now warmed up and the problem doesn't happen warm.

I think the purpose of the check valve is to retain vacuum in the brake booster in the event the engine stops running, giving you one or two last braking cycles with the power assist. If it weren't there, you would get the same very hard pedal you experienced when the valve was frozen, if the engine died while you were blasting down the highway.

Sounds kind of important to me. I wouldn't remove it.

I'm starting to think part of the problem is that it is in the horizontal section of the hose. This would reduce the tendency for any moisture to drain away from it. I wonder if you could re-orient the hose to make it drain better?

 

[Garth]

I have an 01 H-6 too and my car has done this for a year...warm or cold...I would like to know what the fix is...

 

[teblhasa]

That's interesting to know I'm not the only one that suffers this problem. My car will act up when its cold out, freezing usually the 2nd time the brake is pressed on a cold startup, and normally goes away after a half minute to minute of pumping the brakes. I haven't had a mechanic check it out yet, although it would be interesting to see what they report and IF they can reduplicate the problem.

I think if more people are having this problem, maybe we need to report it to the NHTSA (or whatever the initials for that council are) since it is a safety concern. Has anyone experienced this while driving, or is it only when taking off after a cold start?

 

[nipper]

This is a common issue. Other cars can suffer from it alos, be thankful it only happens on startup.


First to clear up one thing.

YOU DO HAVE BRAKES

We are spoiled by power assist everything. It just takes alot more force to stop the car. Blu gets this all the time. Usually 5 firm brake applications with the car running will break loose the stuck valve. Usually three is enough. Practice this so you can feel it in your driveway. You will feel the valve break loose and power assit coming baback.

What you can do otherwise.
1- Replace the check valve.
2- Spray the check valve with WD40.
3- Make it a habit of doing what i said in cold weather.

Condenstaion from a warm egngine cooling down collects on the valve and freezes. WD 40 cleans up the junk on the valve and keeps moisture away.

You havent lived till it happens on the passenger side of the power brake booster. Melting snow from boots ices up on the atmosphere side of the booster. Scary.

It used to be suggested that one goes out and finds a huge parking lot or empty road, and coast the car in neutral and engine off to get the feel of what no PS or PB feels like. Luckily the cars have gotten so reliable that we dont do this anymore. But with brakes, one has to be prepared. You lost the assist, but the car will still stop, it will just be 10x's harder to do.

 

[Garth]

hey nipper..I have the H-6 motor...where is this valve located? TIA...Garth

 

[nipper]

i need to buy an H6 so i can answer . Follow the line from the booster to the intake manifold.


nipper

 

[Garth]

ok...that sounds too easy! I will thanks!:2:

 

[rcy]

This is a common issue. Other cars can suffer from it alos, be thankful it only happens on startup.

Since 1988 I`ve owned 15 vehicles. This is the first one that`s ever done this, and that`s 20 winters I`ve been through.

Is this something that happens as the vehicle ages and `gunk`builds up in the check valveÉ Would buying a new hose (which would have a new check valve in it) solve this problemÉ

Cheers.

P.S. What the heck is wrong with my question marksÉ

 

[nipper]

Since 1988 I`ve owned 15 vehicles. This is the first one that`s ever done this, and that`s 20 winters I`ve been through.

Is this something that happens as the vehicle ages and `gunk`builds up in the check valveÉ Would buying a new hose (which would have a new check valve in it) solve this problemÉ

Cheers.

P.S. What the heck is wrong with my question marksÉ

I should have said a common subaru issue,

New hose wont help. but cant hurt. Its mostly the gunk from combustion that builds up over the years.


nipper

 

[rcy]

Just filed a complaint (on line) at www.nhtsa.dot.gov

Encourage others who have experienced this to do the same. Maybe Subaru can come up with a new check valve or something if forced to.

 

[docgene]

Brakes freezing up

Thanks for all the replies. Time to see the mechanic.

 

[floatingcloud]

This is a common issue. Other cars can suffer from it alos, be thankful it only happens on startup.


First to clear up one thing.

YOU DO HAVE BRAKES

We are spoiled by power assist everything. It just takes alot more force to stop the car. Blu gets this all the time. Usually 5 firm brake applications with the car running will break loose the stuck valve. Usually three is enough. Practice this so you can feel it in your driveway. You will feel the valve break loose and power assit coming baback.

What you can do otherwise.
1- Replace the check valve.
2- Spray the check valve with WD40.
3- Make it a habit of doing what i said in cold weather.

Condenstaion from a warm egngine cooling down collects on the valve and freezes. WD 40 cleans up the junk on the valve and keeps moisture away.

You havent lived till it happens on the passenger side of the power brake booster. Melting snow from boots ices up on the atmosphere side of the booster. Scary.

It used to be suggested that one goes out and finds a huge parking lot or empty road, and coast the car in neutral and engine off to get the feel of what no PS or PB feels like. Luckily the cars have gotten so reliable that we dont do this anymore. But with brakes, one has to be prepared. You lost the assist, but the car will still stop, it will just be 10x's harder to do.

Thank you!
my 2002 Subaru outback has happened this for two times when under -20c. scary! once on the road once on parking lot. ****.
I'll follow your suggestions.

 

[whiteOutback]

Hello All. This happened to both of my 2003 subaru outback a few times. Scary sliding down the driveway as if the car is not going to stop. Happened when it is very very cold, outside temperature below 20 degrees.

Can someone please clarify where is this check valve and vacuum line we are talking about. If you know, please post. You might be doing a great service. Is this the vacuum line from the brake booster ? Following this line to where it connects to the engine or is it beyond that?

No doubt, Northeast owners and those in the snow belt should look into this item as a regular maintenance from now on. Clean or replace the check valve every 60K miles.
De-gunk the hose by removing the vacuum line out of the car, run soap and water solution, let it dry and re-install. I don't know for sure, this is just ideas I am throwing into as possible solution.

 

[mikec]

Yes, a check valve is in the vacuum line from the brake booster [I'm assuming that the 00's subarus are the same as the 90s]. You can feel the check valve by running your fingers down the rubber tube, but you can't get the check valve out. The plastic check valve looks like it costs about 15 cents.

My sticking occurred in the summer and was random. I went to the junk yard and just replaced it. Even after I cut the old check valve out, I couldn't figure out why it was sticking.

 

[whiteOutback]

Thanks mikec. Looks like replacing the booster hose with the built-in check valve is the straight cut option to fix this for at least another 60K or 75K miles.

On the interim while I locate a new hose, I am thinking of doing this. Following the air flow, spray WD-40 into the hose, then blow compressed air to push out any liquid inside the hose, let it air dry, check for one way air flow, and re-install.

Thanks again, hopefully, we can help some owner out there.

 

[nepbug]

Yep, follow the line from the brake booster to the intake manifold, it's in there.

You have to replace the whole line, but you might be able to fix yours.

Pull it off and them flush some isopropyl alcohol down it, let it dry, then spray some WD-40 down the tube (make sure to let any excess drip out), it will help prevent future moisture buildup. If that doesn't work, buy a new line from Subaru

Sent from AutoGuide.com App

 

[whiteOutback]

thanks nepbug. That is already my action plan when the weather warms up a bit this weekend.

 

[steved]

Mine does this also...

I'm like Nipper, I know it does it and I'm the only driver; so I know it will go away after a few HARD applications of the brakes. I've found that moisture in the vacuum lines causes the EGR to throw a CEL in addition to the brake issue. I blew out the vacuum lines for the EGR and that solves the problem...haven't tried that on the brake booster.

It will also go away if you simply let the car warm up before driving...engine heat will warm the components up, but that's not an option for those of us that turn key and drive.

 

[citizenduane]

My 06 outback's brakes locked up but not entirely.(when I took my foot off the gas the car would slow down quickly) my mechanic pulled the vacuum hose off the master cylinder then put it back on and the the car functioned properly for 15 -20 minutes. I have an appointment wit Subarachnoid dealer next week. How muc will this party cost ?