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Hi all,

 

I am new to the group and recently bought a 2003 Legacy L wagon for delivering news papers. The brake pedal works normally when first depressed, but in a few seconds slowly goes to the floor. I had replaced the brake pads and hardware on all four corners along with a caliper on the right front. I took it to Monroe Muffler to have the brakes bleed and the fluid replaced. The brakes worked fine for maybe 120 miles and then this problem arose. I jacked it up and gave it a good look over but can see no indication of leaking brake fluid. The brake light is not illuminated. Any suggestion would be appreciated. Thanks.

 

Steven

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I think there is a recall on that year (not sure but you should check), Brake line corrosion issue. My 05 has that recall as well. 

 

------Brake light will only illuminate if the fluid is low (aka pads worn or leak)

 

Your breaking system is hydraulic. So it consists of a piston (located in your master cylinder), lines, and another set of pistons in each caliper. Hydraulic fluid (break fluid) in the lines must be air and contaminate free for proper operation.

 

 

Its possible that your fluid is contaminated. causing brake fade.  I know you said the fluid was changed but maybe they goofed doing it or just said they did. 

 

If you had a leak it could be at the master cylinder, at any part of the brake lines running all over the car, or at the calipers. Any one of these would cause this issue. 

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I can smell brake fluid when it leaks, even if the leak isn't readily visible. Pop your master cylinder brake fluid cap and smell it (don't let it drip and touch painted surfaces as it'll eat the finish right off), then crouch and smell for that around the car. It's easier to smell in a garage or low wind.

 

Brake lines can rot up above the rear crossmember areas. It can also leak going near the front brakes. If it's not raining, start pumping the brakes while parked (do this at home) then quickly get out and look if it's dripping on dry pavement. If you don't see anything, get on your back and look up under the unibody at each side of the car, and see if the underside has a wet spot, and try and visually follow the brake lines from each rotor. 

 

If it has an external leak, you'll find it eventually. Hopefully it's not the master cylinder.

Edited by Bushwick
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brake fade will have reduced stopping power/brake effectiveness for the pedal travel/pressure but will not result in the pedal dropping like that. If the pedal is dropping without increasing effort/force then the fluid is going somewhere. May be an external leak (easy to find) or leaking internally to the master cylinder.

 

I'd actually prefer an internally leaking master cylinder than having to run new lines but that's just me.

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Do you have ABS?  If the person at Monroe drained out all the brake fluid, then refilled and bled, they may have not followed the proper procedures for the ABS.  You may need to go to the dealer and get them bled there.  Some systems need the dealers scan tool.

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+1 on it being an internal leak in the brake master-cylinder.

 

You have 2 options:

1. Put new seals in the master cylinder. You may be able to buy a kit for this, or

2. Buy a new master-cylinder.

 

If this was my car, I would go with a new master-cylinder; it's quicker, and more likely to be successful, and only costs a few $$ more. Once it's done, it will probably never fail again in the life of the car.

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+2 on it being an internal leak in the brake master-cylinder. If you can't find any external leaks of brake fluid, or any brake fluid spots on the garage floor, or where you park it over night, or the brake fluid level remains high in the reservoir, then it is highly likely a bad master cylinder.

 

I don't think I would recommend going to a chain muffler shop for brake work. They are really exhaust specialists, and prolly not good at other mechanical repairs. Go to a good repair garage, or dealership for quality brake work, if you are not able to do the work yourself.

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Thanks for all the responses and I appreciate your help. The vehicle does have ABS and is why I did not attempt to bleed them myself. I am able to get the vehicle back into Monroe today and they said over the phone that it may be air still in the system. We will see. I agree Monroe may not be the best choice but the garage I use was backed up and I was wanting to get the vehicle on the road.

 

After thinking about this issue some more I agree that the leaky master cylinder is probably the culprit (if the rebleed doesn't fix it). After the initial pedal pressure goes away there just isn't any pressure build up from pumping the brakes and I can find no indications of leaks. I will post again as to what the problem was. 

 

Steven

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  • 6 months later...

does this sound logical to you?

 

when replacing the master cylinder, after the new one is reinstalled,

if you compress the brake calipers , one or more,

you will force brake fluid and any air in the brake line at the mastrer back up into the reservoir.

this will eliminate the need to completely bleed the entire system?

 

true or false????

 

thanks.

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I think false.  You have to bench bleed the MC before you install it, forcing air back into it after installing it will undo the bench bleed.  Better to bleed the system properly.  BTW, if you have ABS and you force the brake fluid to go upstream, it can damage the ABS module.

Edited by keith3267
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Only thing in terms of ABS is getting air in the system, possibly setting a code or it not being able to function.

But you'd know if there's air in the system as the brake pedal would be mushy but would get firm after a few pumps. But as soon as you let off the pedal you'd have to pump it again to get it solid.

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