Changed pads, now brakes are mushy?

Handling, suspension, and brake tuning discussions
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Lancer
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Joined: Mon Jul 15, 2002 3:53 pm

Changed pads, now brakes are mushy?

Post by Lancer »

Changed my front brake pads over the weekend. Only 1mm of pad left! Everything went really easy, almost too easy. Then I went to test them out. There was hardly any resistance all the way to the floor board. So I tried bleeding the brakes. After 20 min. of bleeding both sides, there's still no change. They work, but only very close to the floor board?What did I do wrong? There's no leaks. and Yes, the shims are inplace.
18" Enkei's & Kumho Ecsta's-------UNICHIP Eibach Sport springs----------Morroso oil pan Injen CAI & Oil cap----------Stage 2 FI cams Custom Exhaust-----------TRD Supercharger AEM alt. pulley -------JSP Carbon Fiber hood 380cc injectors----DC Sports ceramic header
scherry2
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Re: Changed pads, now brakes are mushy? (Lancer)

Post by scherry2 »

did you fill the master cylinder and pump the brakes before you bled them?
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joatmon
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Re: Changed pads, now brakes are mushy? (Lancer)

Post by joatmon »

Do you have ABS?Did you bleed just the front, or both the front and back?
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sbaker
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Re: Changed pads, now brakes are mushy? (Lancer)

Post by sbaker »

Changed my pads last weekend without any problem. As long as you didn't open the bleeders to let pressure off of the calipers the only thing you should have to do is pump the brakes up before you start the car and take off in it... Also possible that you may need to adjust your rear brakes [if drum]; otherwise you should be set. If you do have ABS you'll have to bleed the brakes in a sequence.PS adjusting the rear brakes doesn't require removal of the drums on Vibes, unlike most foreign brake systems
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northvibe
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Post by northvibe »

yeah ive had to pump my brakes on some cars after a break change
Lancer
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Re: Changed pads, now brakes are mushy? (joatmon)

Post by Lancer »

No I don't have ABS. Yes I kept the master cylinder filled. I bled just the front thinking that the fluid doesn't circulate through the whole system. Is that right?I tried pumping before starting and they get really tight then, but as soon as I start the engine they get mushy again. ???I think the car is just acting up 'cause it's just about paid for.
18" Enkei's & Kumho Ecsta's-------UNICHIP Eibach Sport springs----------Morroso oil pan Injen CAI & Oil cap----------Stage 2 FI cams Custom Exhaust-----------TRD Supercharger AEM alt. pulley -------JSP Carbon Fiber hood 380cc injectors----DC Sports ceramic header
scherry2
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Re: Changed pads, now brakes are mushy? (Lancer)

Post by scherry2 »

the master cylinder is one unit serving both front and rear, not like the old days where it was divided front and rear.have someone pump them real slow while the car is running and watch the master cylinder then bleed all four brakes.
Baltovibe
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Re: Changed pads, now brakes are mushy? (Lancer)

Post by Baltovibe »

After looking in the service manual, I'll add a few ideas out here.Normally, when the front disc brakes are replaced, the system should not need bleeding because there is little chance of air getting into the system.A low brake pedal is indicative of a few things. It could be air in the system, internal leakage in the master cylinder, or a faulty brake power booster. I learned early on that when bleeding brakes, never let the brake pedal go to the floorboard, but instead, put a small board on the floor first so that the brake pedal stops before hitting the floor. The reason is because the brake pedal has a normal path of travel, which extends the master cylinder's primary piston a normal certain amount. If the brake pedal is allowed to go to the floor, that piston gets extended beyond its normal travel, and any dirt accumulation on that extended portion of the piston will get onto the seals and ruin them. That will cause internal leaks within the master cylinder.So, the manual recommends checking for internal leaks first, by slowing pulling the master cylinder just far enough away from the brake power booster to check for any leakage around the primary piston. If any leakage is found, then the primary or secondary seals are leaking and the master cylinder needs overhauling or replacement.If no internal leaks are found, then the manual recommends bleeding the brakes in this order, making sure the brake fluid never goes below the minimum level in the master cylinder:1) Master Cylinder (both front brake pipe and rear brake pipe at the master cylinder)2) Right Rear brake bleeder valve3) Left Rear brake bleeder valve4) Right Front brake bleeder valve5) Left Front brake bleeder valve.All this is assuming that there are no external leaks.Obviously this is a quick rundown ... the manual goes into a lot of details and other test procedures that is well beyond the scope of most backyard mechanics.
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Lancer
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Re: Changed pads, now brakes are mushy? (Baltovibe)

Post by Lancer »

Thank's for all the tips!! I'll give it another try this weekend.
18" Enkei's & Kumho Ecsta's-------UNICHIP Eibach Sport springs----------Morroso oil pan Injen CAI & Oil cap----------Stage 2 FI cams Custom Exhaust-----------TRD Supercharger AEM alt. pulley -------JSP Carbon Fiber hood 380cc injectors----DC Sports ceramic header
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