4eat cause of weak brakes?
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This is a discussion on 4eat cause of weak brakes? within the General Maintenance, Troubleshooting & Accidents. forums, part of the Tech & Modifying & General Repairs category; Hey all, I'm not sure where to put this question first off. But since it's a brake problem i'll start ...

  1. #1
    Registered User Tinywagon's Avatar
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    4eat cause of weak brakes?

    Hey all,

    I'm not sure where to put this question first off. But since it's a brake problem i'll start here. I've also done alot of searching but thus far i've come up short.

    The car,
    02 wrx wagon with 4EAT Approx. 117,000 miles, Daily Driver, never tracked.

    Mods:
    Sti Alternator
    Goodrige steel lines
    Hawk HPS pads
    new stock rotors
    ATE superblue fluid
    Agency lightened crank Pulley
    Grimspeed air/oil separator

    The problem:
    My brakes have always been weak from a cold start so much so that I have to throw it into neutral in order to completely stop until the car warms up. I have gone through several iterations of brake pads (Stock pads, Brake Pro's Metal Matrix, Hawk HPS) and it has always done this. If I leave the car In drive while i'm stopped and the engine is cold, the brakes dont have enough bite to keep the car from slowly rolling forward even if the pedal is fully depressed. Then when I do let off the brakes they release with a loud, CLUNK. it can be especially heard on the rears.

    I had all four rotors replaced as well as new pads put on and the entire system was bled with new fluid two weeks ago and my mechanic, a subaru specialist, told me that my rear rotors were extremely warped, so much so that they could not be machined, a phenomenon he had never seen. Especially considering that the rotors were only two years old.

    The other odd thing is that, this doesn't just happen in the winter. It happens all year round. So it's not just a cold thing. I've had the master cylinder checked and apparently there are no issues there.

    The only thing I can think of is that for some reason my tranny isn't shifting into neutral when at a complete stop. I'm not sure if it's even supposed to do that but I can tell you that once it's warmed up, the car has the ability to stop better, but it still needs to be tossed into neutral if I need to stop quickly, like a panic stop.

    SO i'm at a loss as to how to procede. Advice would be preferable, but opinions would be useful.

    Thanks in advance,
    Tiny.
    "if you are going to tell someone the truth you had better make them laugh otherwise they'll kill you" - George Bernard Shaw.
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  3. #2
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    Check the brake booster and the vacuum lines... Maybe plugged?
    '02 WRX 4EAT, 311,000KMs/194,500Miles, Sold. Best car I ever had. '09 STi stage 1, hope this one will be good too...

  4. #3
    Supporting Member mjboudreaux77's Avatar
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    My stock rotors warped on my 07 WRX within 10K miles. Don't believe the "phenomenon he had never seen" junk - warped rotors happen all of the time. I will admit that warping in 2 years on rear brakes is fast, but certainly not unheard of. 80% of your stopping will come from your front brakes.

    I can't believe you are driving this car. You are describing something that I would feel completely unsafe in.

    As far as the tranny - even if the car is staying in drive, your brakes should still stop it. If you have a tachometer, you should be able to tell if the car is staying in gear or not. I don't think this is your issue.

    Putting Hawk HPS pads on makes your issue worse. These are ceramic brakes and need to be warmer in order to have bite. If you had a good set of stock pads, and this was still happening, then...

    1.) Are you leaking brake fluid?
    2.) Is your pedal going to the floor? Or is it stopping before that and you just can't push any more?
    3.) When you clean your wheels, are you using a chemical that specifically says to not get on the rotor?
    4.) Are your 4 sets of pads wearing evenly?
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  5. #4
    Registered User Tinywagon's Avatar
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    Quote Originally Posted by mjboudreaux77 View Post
    If you had a good set of stock pads, and this was still happening, then...

    1.) Are you leaking brake fluid?
    2.) Is your pedal going to the floor? Or is it stopping before that and you just can't push any more?
    3.) When you clean your wheels, are you using a chemical that specifically says to not get on the rotor?
    4.) Are your 4 sets of pads wearing evenly?
    1. No
    2. Almost all the way. But that doesn't seem to ad anymore force.
    3. No
    4. Yes
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    Supporting Member mjboudreaux77's Avatar
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    Given your other answers, it sounds like the brake booster/vacuum line needs to be further looked at. Sounds like you may have an air leak on the vacuum line.
    If I don't die by Thursday, I'll be roarin Friday night - Jimmy Buffett

  7. #6
    Registered User Tinywagon's Avatar
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    How does one check such a thing?
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  8. #7
    Administrator Trainrex's Avatar
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    Quote Originally Posted by mjboudreaux77 View Post
    Given your other answers, it sounds like the brake booster/vacuum line needs to be further looked at. Sounds like you may have an air leak on the vacuum line.
    I'm sorry, that's incorrect.

    If the booster failed, or there was vacuum leak present, the pedal would be rock hard and braking would require much more effort, but would still be effective.

    You have air in your lines and/or your master cylinder is faulty. Naturally this is assuming you don't have a fluid leak somewhere. Odds are the master is just fine. You need to properly bleed your brakes before you drive any further. Whomever installed the Goodrige lines did not properly bleed the system.

    Also, the car doesn't switch in to neutral when you stop. The transmission is always engaged until you either switch to neutral or park.

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    When exactly did this problem start? You say the brakes "have always been weak"

    If the problem existed before the SS lines and the thousands of pads you've tried, then I doubt they're the culprit.

    Advice? get a rental or borrow a car. I wouldn't pay out a dime if I was your insurance company and you got in a wreck in this car.

  10. #9
    Supporting Member mjboudreaux77's Avatar
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    find the problem?

    I really don't think this is air in the lines. They have been bled twice, and he is not describing a spongey response on the pedal.

    I would also say a caliper needs to be looked at - but you said all 4 pads are wearing even.
    If I don't die by Thursday, I'll be roarin Friday night - Jimmy Buffett

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    Old post I know, but if you have checked your brakes over then it sounds like your engine is idling too high after a cold start and that your brakes are unable to stop the car. My 01 automatic legacy also idles higher when it first starts and it takes a little more of a push on the brakes to stop the car, but never bad enough that the car can pull itself still while braking. What are you idling at when you first start up?

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