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Cold weather brake problems


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74 replies to this topic

#1 OswaldtheBold

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Posted 24 January 2007 - 11:55 PM

'97 Legacy. First thing in the morning, when it's very cold (like 0 degrees), when I first start the car, the brake pedal won't go down (just the pedal free travel, but no more). Very hard to push the pedal at all and almost no pedal travel. Rolling backwards in my driveway at about 10 mph, I can barely stop. After several tries, things return to normal, and no further problems.
It only happens first time you start up when it is very cold. If I let the car warm up for 5-10 minutes before moving, no problem. If it is above 0 degrees, no problem.
I thought it felt like no vacuum brake boost. We replaced the brake booster with a new one, but no improvement.
I have not been using the parking brake at night, so that is probably not the problem.
The ABS light comes on when you first turn the key on, so I know the light works, then it goes out when you start it and does not return, so I would guess the diagnostics don't think it's an ABS problem.
My other '97 Legacy never has this problem, starting both of them at the same time on the same mornings.
Any suggestions?

#2 nipper

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Posted 25 January 2007 - 12:59 AM

'97 Legacy. First thing in the morning, when it's very cold (like 0 degrees), when I first start the car, the brake pedal won't go down (just the pedal free travel, but no more). Very hard to push the pedal at all and almost no pedal travel. Rolling backwards in my driveway at about 10 mph, I can barely stop. After several tries, things return to normal, and no further problems.
It only happens first time you start up when it is very cold. If I let the car warm up for 5-10 minutes before moving, no problem. If it is above 0 degrees, no problem.
I thought it felt like no vacuum brake boost. We replaced the brake booster with a new one, but no improvement.
I have not been using the parking brake at night, so that is probably not the problem.
The ABS light comes on when you first turn the key on, so I know the light works, then it goes out when you start it and does not return, so I would guess the diagnostics don't think it's an ABS problem.
My other '97 Legacy never has this problem, starting both of them at the same time on the same mornings.
Any suggestions?


master cylinder or a frozen brake system (extreemly rare). There was a test for the Pwr brakes, but since you replaced that its the master cylinder.

nipper

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#3 Juan

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Posted 25 January 2007 - 01:20 AM

There was a recall on all '97s for master brake cylinders that fail in extreme cold. Sounds like they missed yours.

Juan

#4 nipper

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Posted 25 January 2007 - 01:22 AM

There was a recall on all '97s for master brake cylinders that fail in extreme cold. Sounds like they missed yours.

Juan


cool i was loooking for that :)
hrmm ill guess ill find out thrusday when its 15 F here if mine works.

nipper

#5 weddes05

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Posted 25 January 2007 - 07:54 AM

maybe also check the condition of the powerbrake check valve. it is hidden in the middle of the hose that goes from the intake to the booster. pull it off and shoot air through either direction when it is cold. air should only flow one way.

#6 OB99W

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Posted 25 January 2007 - 10:56 AM

There was a recall on all '97s for master brake cylinders that fail in extreme cold. Sounds like they missed yours.

Are you sure about the '97s? There was a recall on some MY98s and MY99s, but the defect caused the pedal to go to the floor (NHTSA Campaign ID Number 99V040000).

#7 OswaldtheBold

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Posted 25 January 2007 - 02:39 PM

maybe also check the condition of the powerbrake check valve. it is hidden in the middle of the hose that goes from the intake to the booster. pull it off and shoot air through either direction when it is cold. air should only flow one way.


Which way should it flow?

#8 weddes05

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Posted 26 January 2007 - 08:16 AM

there should be markings on it that show engine -->. normally it will only fit well the one way. If I am thinking correctly you should be able to blow through the booster end and not through the engine end..... but its early

#9 srs_49

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Posted 30 January 2007 - 05:03 AM

I've been fighting the same problem with my wife's '92 Outback. I replaced the master cylinder back in July. Could not tell back then if it solved this problem, since it only shows up when cold. But, now that's it's finally gotten cold, the problem is still there.

The master cylinder recall was for brakes that would not release, not for brakes that were hard to apply.

I just ran the brake booster test suggested by Nipper in a post to my earlier thread.

"hrmmm do you have a long hill by your house thsts straight and safe to try a test on?
With the car off pump the barkes 10-15 times. With your foot on the brake pedal start the car, the pedal should move to the floor. If it doesnt you have a bad booster. Do this test first thing in the morning when the car usually has no brakes."

The brakes reacted just as he described. So, at least in my case, this problem is not master cyclinder related. I'm going after the vacuum booster, or maybe the one-way valve some else suggested to look at.



#10 Reveeen

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Posted 30 January 2007 - 05:24 AM

A few times (a very few) I have seen power boosters that get moisture in them act as you describe, I'm 50+ years old and I've seen it maybe 1/2 a dozen times. Usually when a master cylinder fails when cold you end up with no pedal.

#11 nipper

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Posted 30 January 2007 - 10:11 PM

Thats what im having. SO question is, what do we do about it ?


nipper

#12 cookie

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Posted 31 January 2007 - 01:01 AM

I think I also recall a problem folks had that the pedal stayed hard and the brakes had little pressure. I believe subaru said that was a few defective master cyls. Usually when I've seen that it was the booster.

#13 srs_49

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Posted 31 January 2007 - 09:19 AM

Thats what im having. SO question is, what do we do about it ?


nipper


I'm going to try and look at the check valve this weekend. I'm all for trying the cheaper fix first, though I think I can get a vacuum booster assy on-line for ~$115, which isn't too bad. I'm sure the dealer would want to do the booster assy (more $$$ for them), but I don't trust 'em to touch the car.

#14 OswaldtheBold

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Posted 01 February 2007 - 02:00 PM

There was a recall on all '97s for master brake cylinders that fail in extreme cold. Sounds like they missed yours.

Juan

I just checked with the service department at my local Subaru dealer. They told me the master cylinder recall was for 1998, and it did not apply to '97. They did not show any brake system recall for the '97.

Since I've already replaced the booster, I'm now thinking master cylinder. But, any chance it could involve the ABS system, even if the ABS light doesn't come on?

#15 nipper

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Posted 01 February 2007 - 02:49 PM

I just checked with the service department at my local Subaru dealer. They told me the master cylinder recall was for 1998, and it did not apply to '97. They did not show any brake system recall for the '97.

Since I've already replaced the booster, I'm now thinking master cylinder. But, any chance it could involve the ABS system, even if the ABS light doesn't come on?


ABS in a subaru is flwo through design. It doesnt get involved in the break circuit unless there is a puter malfunction or the wheel speed dictates it so. The failure mode is either it doesnt work or it constantly cycles.
One way to find out is just pull the fuse and let the car cold soake, but i really dont think its the ABS.


nipper

#16 ccrinc

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Posted 02 February 2007 - 12:35 AM

Since we're having a very cold winter here in Denver, I'm hearing this a lot. Both of my cars, '92 SVX and '92 Legacy Turbo Touring Wagon LE have exhibited this. (Not every day though :confused: )
Other people have had this happen on Legacys, Outbacks, Foresters, etc, etc.
I don't believe there's any real failure involved. This is a hydraulic system, and it's just too darn cold for the fluid to act normally until it's circulated a bit.

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#17 srs_49

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Posted 02 February 2007 - 07:32 AM

Since we're having a very cold winter here in Denver, I'm hearing this a lot. Both of my cars, '92 SVX and '92 Legacy Turbo Touring Wagon LE have exhibited this. (Not every day though :confused: )
Other people have had this happen on Legacys, Outbacks, Foresters, etc, etc.
I don't believe there's any real failure involved. This is a hydraulic system, and it's just too darn cold for the fluid to act normally until it's circulated a bit.

Emily
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I disagree in that I sure there is a failure/malfunction involved. Our '92 Outback exhibits the problem when the temperature gets below 32 deg F, which is not really very cold. I have owned ~12 vehicles over 40 years of driving, living in the same general area, and the Outback is the only one that has ever exhibited this kind of problem.

One of the things we all could do is file a report with the NHTSA and have them open up a safety-related case. If they get enough complaints, they may do an investigation and ultimately, force Subaru to issue a recall or at least look into the problem. You can do this on-line at the NHTSA web site.
Try http://www-odi.nhtsa.dot.gov/ivoq/

#18 OB99W

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Posted 02 February 2007 - 08:24 AM

[...]I don't believe there's any real failure involved. This is a hydraulic system, and it's just too darn cold for the fluid to act normally until it's circulated a bit.

Uncontaminated brake fluid will exhibit increased viscosity at lowered temperatures, but it shouldn't get to the point of causing hydraulic problems at temps typically seen in the US. DOT-3 or DOT-4 glycol-based brake fluids are "hygroscopic"; they absorb moisture (water) -- (DOT-5 type is silicone-based and has different characteristics). Rather than the water pooling in spots in the system, it should normally get dispersed in the fluid, making it tolerant of at least some water-contamination.

It's recommended to flush brake fluid periodically, mostly due to concern over the moisture causing lowering of the boiling point of the fluid and possibly corrosion of hydraulic system parts. However, I suppose (I don't have specific info on this) it would be possible for the fluid to have a sufficient moisture content to make it more susceptible to problems at extremely low temperatures. Certainly if you typically drive through flooded areas or ford streams while off-roading, you should consider flushing the brake system periodically.

Some people think that DOT-5 fluid would be better for their car, but it has its own drawbacks. While it isn't hygroscopic, any water that does get into the hydraulic system will not be dispersed in the fluid, but remain concentrated in certain areas; of course, it could then freeze or boil at those points. DOT-5 fluid also aerates (gets air bubbles in it) more readily than either -3 or -4, making for a less-firm pedal than most of us like.

I'm not suggesting that the problem discussed in this thread either is or isn't a problem with the fluid or the master cylinder, and there may not even be a common cause. Under any circumstance, it would seem that it isn't something to be ignored, and the suggestion of reporting experiences to NHTSA is probably a good idea.

#19 nipper

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Posted 02 February 2007 - 10:46 AM

For our own saftey in bitter cold weather, i must suggest that before you move the car pres the break pedal a few times. My gut is telling me that its not the master cylinder, but condensation in the booster freezing.

nipper

#20 OB99W

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Posted 02 February 2007 - 01:37 PM

For our own saftey in bitter cold weather, i must suggest that before you move the car pres the break pedal a few times.

That seems prudent.


My gut is telling me that its not the master cylinder, but condensation in the booster freezing.

IMO, certainly a possibility. My discussion of brake fluid was due to the topic having been brought up, not because I think it's the most likely culprit. As I said, DOT-3 and -4 disperse moisture, which makes a hard freeze at some point in the hydraulics unlikely at any reasonable temperature.

#21 nipper

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Posted 02 February 2007 - 03:07 PM

That seems prudent.


IMO, certainly a possibility. My discussion of brake fluid was due to the topic haven't been brought up, not because I think it's the most likely culprit. As I said, DOT-3 and -4 disperse moisture, which makes a hard freeze at some point in the hydraulics unlikely at any reasonable temperature.


my rear breaks were done 15,000 miles ago. The shop i use always blleds the breaks in a sufficient amount to displace all the old fluid (i asked and have used them for years).

Cars in general are made to survive from -25 to 135 F (granted they may be a little grumpy). I've seen frozen breaks at the drum, but even that is rare (and usually the parking brakes fault).

I am seeing a pattern here i dont like, and i think we all need to hit the nhtsa website at once to get thier attention.


Does anyone with newer subaries have this issue?


Its supposed to get to 15 F here on tuesday, ill have to watch out for this, though i will admit the remote starter tends to avoid this problem. If i go out to a movie ill see if it happens again.


nipper

#22 yohy

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Posted 02 February 2007 - 04:01 PM

1997 Legacy L sedan, auto at 155K started to exhibit this cold weather brake issue during the last cold snap for the first time. Now brake fluid changed last fall and at that time, each brake was pulled apart, lubed and checked for proper operation. With this, I am leaning away from a "at the wheel" brake issue.

srs_49, did you ever look at your power brake check valve as a possible source of the problem (mentioned by weddes05)? On my end, the car is now a few hours away (kid-college), so the diagnosis is long distance.

#23 OB99W

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Posted 02 February 2007 - 05:58 PM

That seems prudent.


IMO, certainly a possibility. My discussion of brake fluid was due to the topic haven't been brought up, not because I think it's the most likely culprit. As I said, DOT-3 and -4 disperse moisture, which makes a hard freeze at some point in the hydraulics unlikely at any reasonable temperature.

Ooops, instead of "haven't been brought up" I meant to say "having been brought up". Maybe my brain fluid is too cold ;). I'll edit that post, because otherwise it's a bit confusing.


[...]Cars in general are made to survive from -25 to 135 F (granted they may be a little grumpy). I've seen frozen breaks at the drum, but even that is rare (and usually the parking brakes fault).

I had a Pontiac Tempest which let water get into the parking brake cable sheath. I learned to not set the brake when it was below freezing (after getting stranded twice!), until I changed the cable out for a new one with better seals.

Does anyone with newer subaries have this issue?

Its supposed to get to 15 F here on tuesday[...]

My '99 is a little newer than yours, and it's usually about 10 deg colder here than where you are, but it hasn't had the problem discussed in this thread. It did fall into the range of VINs that had the master cylinders that were bad when cold, and it got a new one several years ago under the recall even though mine never exhibited that problem either.

#24 nipper

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Posted 02 February 2007 - 06:20 PM

My '99 is a little newer than yours, and it's usually about 10 deg colder here than where you are, but it hasn't had the problem discussed in this thread. It did fall into the range of VINs that had the master cylinders that were bad when cold, and it got a new one several years ago under the recall even though mine never exhibited that problem either.


So maybe it is just the cars before 99 that has this issue


nipper

#25 RallyKeith

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Posted 05 February 2007 - 09:14 AM

My 96 just did this this morning. 6 degrees outside, super stiff pedal and almost no braking. By the third or fourth time I pressed the pedal all was fine. This was after about 1 minute of idle, and then 3-5 minutes of driving. The temp gauge on the engine had moved somewhat by the time the pedal acted normally. Now, the funny thing is, I just did an engine swap on this car this weekend, so the vaccum hose to the booster was just hanging in mid air from saturday afternoon until sunday afternoon. The fluid in my brake resevoir looks dirty (brown) so I think the first place I'm going to start is with a complete fluid flush of the brake system.




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