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My 98 OBW that my wife drives has developed weak brakes. It stops straight, pads in the front are 2 years old, rear pads 6 months old. I bled out the old fluid about 3 years ago, filled with new DOT 3. There are no odd noises when applying the brakes. Pedal seems to go down a little low upon applying the brakes. The problem is that pushing down hard on the pedal produces weak stopping power. There is not even enough braking power to come close to locking up the brakes, or setting off the ABS. I wonder if the rear brakes are working?

 

Should I bleed out the brakes again, or is this a MC problem?? There is no warning dash light.

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has it been like this for 3 years or recently gotten worse or it got notably bad all at once?

 

if you hold pressure on the pedal does it stop and "drift" lower or spongy or?

 

if you pump the brakes really fast, like 3 times down and up and jam on the last time, does that improve things?

 

MC sounds probable.

check brake hoses and make sure they aren't ballooning out, but i haven't seen or heard of that happen to Subaru's.

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There was a recall on the master cylinder that you might want to check into if yours hasn't been done.

 

Would a recall cover the cost of an m/c on a car that is 13 years old, and I am the third owner? I don't know if the m/c is original. How can I find out?

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Some recalls have a ten year window, some do not, you have to check. Either way this is soooo important have it checked and replaced asap.

 

This is not safe.

 

Also a bad PB booster can feel like a bad MC. The MC however will sometimes do it then not do it at the start of the failure.

 

Have you done the PB test?

 

car off

 

pump brakes 5 times

 

press brake pedal

 

start car

 

pedal should move to the floor, if it does PB is ok.

 

Another possability is stuck calipers in the rear nad way out there is bad brake lines but that would make a spongy pedal.

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has it been like this for 3 years or recently gotten worse or it got notably bad all at once?

 

if you hold pressure on the pedal does it stop and "drift" lower or spongy or?

 

if you pump the brakes really fast, like 3 times down and up and jam on the last time, does that improve things?

 

MC sounds probable.

check brake hoses and make sure they aren't ballooning out, but i haven't seen or heard of that happen to Subaru's.

 

Just came back from a test drive to do the testing that was suggested. Brakes seem fine today, brought the car down to a dead stop repeatedly with nothing unusual. I could not detect any sponge in the pedal. The "pump the brakes" test did not improve braking.

 

I did the PB booster test, and the pedal moved slightly to the floor as it is suppose to do.

 

I can't figure out why the brakes felt weak for the last couple of days, and now feel just fine today. I know I am not loosing my mind. I clearly remember the brakes had diminished stopping power, and it concerned me. I can't imagine any slippery build up on the pads to cause problems, but if so, it is not there now. Guess, I will have to keep an eye on the situation to see if it returns.

 

Thanks for all the solid advise.

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This is typical of either a stuck caliper or a failing Master Cylinder.

 

Check everything at the wheels first, dont just look at the pads, swing the calipers up and make sure everything slides.

 

I will follow your advise. What specifically should I be looking for? What would be the evidence that a caliper is stuck, or that the MC is failing?

Thanks Nipper!!

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Sometimes to come to the conclusion of a bad MC you have to rule out everything else. This is not a part that you want to take a wait untill it gets worse to properly diagnose it.

 

Does the pedal sink to the floor when you stand on it with the car running?

 

Have you ever done brakes before yourself?

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Sometimes to come to the conclusion of a bad MC you have to rule out everything else. This is not a part that you want to take a wait untill it gets worse to properly diagnose it.

 

Does the pedal sink to the floor when you stand on it with the car running?

 

Have you ever done brakes before yourself?

 

Nipper.........

The pedal does not sink to the floor when standing on it with the car running.

 

Yes, I do my own brake work. I have replaced calipers, rotors, and pads, and know to lube the slides well. I have used a one man bleeder system to get rid of air in the lines. I have replaced calipers before, when the car pulls to one side because the pad is dragging. It is then, I have found the brake pad worn much more so at one wheel, compared to others. Pretty easy to figure out that the caliper piston is sticking. I wish I had a heat gun sensor to see if one brake is hotter then the others after a drive. That would indicate a bad caliper causing pads to drag. I have never replaced an M/C, but figure it can't be difficult. I have always thought that having to double pump the brake pedal was the indicator that the M/C is bad. Any other thoughts??

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Who wants to double pump in a panic stop, when the internal pressure is the highest.

 

First fix the dragging caliper, next make sure the rears are free. They must move freely, not just a little freely. even if they feel fine clean the pins anyway.

 

 

Even with a heat gun , i would still check all 4 calipers and clean all 4.

 

With a stuck caliper pumping the pedal sometimes helps, and can mimic a bad MC.

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Who wants to double pump in a panic stop, when the internal pressure is the highest.

 

First fix the dragging caliper, next make sure the rears are free. They must move freely, not just a little freely. even if they feel fine clean the pins anyway.

 

 

Even with a heat gun , i would still check all 4 calipers and clean all 4.

 

With a stuck caliper pumping the pedal sometimes helps, and can mimic a bad MC.

 

Good advise........Thanks!

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