Seems like a bad master cylinder. Try that.
Soft pedal?
So I have a 2003 Durango 4.7 liter 4x4 automatic transmission. I recently replaced my rotors calipers pads caliper hoses and brake lines all around everything brand new. I have absolutely no leaks anywhere in any of the fittings lines hoses or junctions. When I bleed my brakes the pedal gets stiff at about 3-4 pumps on each wheel when bled. I am following 100% correct bleeding procedures on the pump method RR RL FL FR And there is no air in the fluid when it comes out. However after being bled and I start the car the pedal goes straight to the floor. When I drive the car will stop if I slam the brake all the way to the floor eventually. I have searched so many different forums and have followed all the tips and nothing is working. Can somebody please help me figure out what is causing this. I have read other threads where others have the same problem but I cannot find a real solution or answer. Should I replace the brake booster and master cylinder as well. Please help
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Should I replace the brake booster and MC as a whole so it’s a COMPLETELY new brake system
Assuming your brakes worked okay before you did all this work, it would be highly coincidental that the master cylinder were to fail at exactly the same time that you put in a complete brake system (minus master and booster). It would be cheaper to buy a reverse bleeder and do it right (air goes up easier than it goes down), than to buy a new master cylinder and find your pedal is still soft after an hour of bleeding. People say the risk with a reverse bleeder is that you are sending crud from your wheel cylinders up to the master cylinder to possibly contaminate it. Maybe, but you are using brand new parts, so this is not an issue. I recently replaced the clutch on a Ford Focus, and with the new slave cylinder, that thing took FOREVER to bleed the conventional way before I got a solid clutch pedal.
I wouldn't be to worried about the booster, but the master does not sound good. I have seen it before when you do a bunch of bleeding on an older master you stir up some crud in the master then it doesn't work good when done. It is very rare for a booster to go bad. Have funShould I replace the brake booster and MC as a whole so it’s a COMPLETELY new brake system
ISo I have a 2003 Durango 4.7 liter 4x4 automatic transmission. I recently replaced my rotors calipers pads caliper hoses and brake lines all around everything brand new. I have absolutely no leaks anywhere in any of the fittings lines hoses or junctions. When I bleed my brakes the pedal gets stiff at about 3-4 pumps on each wheel when bled. I am following 100% correct bleeding procedures on the pump method RR RL FL FR And there is no air in the fluid when it comes out. However after being bled and I start the car the pedal goes straight to the floor. When I drive the car will stop if I slam the brake all the way to the floor eventually. I have searched so many different forums and have followed all the tips and nothing is working. Can somebody please help me figure out what is causing this. I have read other threads where others have the same problem but I cannot find a real solution or answer. Should I replace the brake booster and master cylinder as well. Please help
don't know if this will help or not but I recently did the whole brake system on my 2000 Durango including the master cylinder, rear brake drum cylinders, heavy duty brake shoes and pads, stainless
steel lines and braided steel brake lines to the calipers in front and I still didn't have the braking power that I thought I should have IE: brakes were still a bit spongey. I was told the same thing by one mechanic that the brake booster rarely goes bad. I then took it to another shop to get an alignment and the guy looked over everything and said "Do you know your brake booster is leaking off air". I said no. He replied when you pump the brakes up they'll get stiff but if you just put your foot on the brake you can hear air leaking off the booster. I asked him if that was the reason my brakes felt soft after everything was replaced and he said yep. I couldn't hear it in the cab of the vehicle. He had his associate work the brake pedal while he had his head under the hood and that's how he heard it so I'm going to have my brake booster (that never goes bad🤔) replaced. No amount of bleeding is going to help if the booster is bad. Remember, parts wear out. My Durango is 20 years old , your's is 17 years old. Parts do wear out over time. That may not be the issue but it's definitely worth it to check it out.
steel lines and braided steel brake lines to the calipers in front and I still didn't have the braking power that I thought I should have IE: brakes were still a bit spongey. I was told the same thing by one mechanic that the brake booster rarely goes bad. I then took it to another shop to get an alignment and the guy looked over everything and said "Do you know your brake booster is leaking off air". I said no. He replied when you pump the brakes up they'll get stiff but if you just put your foot on the brake you can hear air leaking off the booster. I asked him if that was the reason my brakes felt soft after everything was replaced and he said yep. I couldn't hear it in the cab of the vehicle. He had his associate work the brake pedal while he had his head under the hood and that's how he heard it so I'm going to have my brake booster (that never goes bad🤔) replaced. No amount of bleeding is going to help if the booster is bad. Remember, parts wear out. My Durango is 20 years old , your's is 17 years old. Parts do wear out over time. That may not be the issue but it's definitely worth it to check it out.
Make sure the ABS controller is centered
I did not say never, in the 50 years I have been working on cars I have only replaced 3 or 4 boosters. and the air leakage is a sign.don't know if this will help or not but I recently did the whole brake system on my 2000 Durango including the master cylinder, rear brake drum cylinders, heavy duty brake shoes and pads, stainless
steel lines and braided steel brake lines to the calipers in front and I still didn't have the braking power that I thought I should have IE: brakes were still a bit spongey. I was told the same thing by one mechanic that the brake booster rarely goes bad. I then took it to another shop to get an alignment and the guy looked over everything and said "Do you know your brake booster is leaking off air". I said no. He replied when you pump the brakes up they'll get stiff but if you just put your foot on the brake you can hear air leaking off the booster. I asked him if that was the reason my brakes felt soft after everything was replaced and he said yep. I couldn't hear it in the cab of the vehicle. He had his associate work the brake pedal while he had his head under the hood and that's how he heard it so I'm going to have my brake booster (that never goes bad🤔) replaced. No amount of bleeding is going to help if the booster is bad. Remember, parts wear out. My Durango is 20 years old , your's is 17 years old. Parts do wear out over time. That may not be the issue but it's definitely worth it to check it out.
So I have a 2003 Durango 4.7 liter 4x4 automatic transmission. I recently replaced my rotors calipers pads caliper hoses and brake lines all around everything brand new. I have absolutely no leaks anywhere in any of the fittings lines hoses or junctions. When I bleed my brakes the pedal gets stiff at about 3-4 pumps on each wheel when bled. I am following 100% correct bleeding procedures on the pump method RR RL FL FR And there is no air in the fluid when it comes out. However after being bled and I start the car the pedal goes straight to the floor. When I drive the car will stop if I slam the brake all the way to the floor eventually. I have searched so many different forums and have followed all the tips and nothing is working. Can somebody please help me figure out what is causing this. I have read other threads where others have the same problem but I cannot find a real solution or answer. Should I replace the brake booster and master cylinder as well. Please help
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