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Brake pedal goes way down to almost floor before working

56K views 18 replies 9 participants last post by  LEVY 
#1 ·
My brakes work, but I have to push the pedal down far before they work. The front brakes were replaced a month or two ago. It doesn't seem related to that repair since this wasn't a problem at that time. It's making me nervous. In the past I would assume the brakes need bleeding, but I've seen enough to ask if it could be something else. We're taking it in tomorrow, but just kind of curious what you guys think it could be.
 
#2 ·
#3 ·
this is just a guess, but since the rear brakes on SXT are disk (rotor, not drum) and no codes/lights or symptoms are present - they probably need to be bled (all fluid exchanged) and ABS modulator needs to be bled (via DRBIII).
The ABS bleeding is very important in this case, since if there's air present in the module it cannot be expelled any other way...
 
#5 ·
The mechanic says they are fine. He's wondering if maybe my hand controls (disabled driver) might need adjusting because with the pedal they are fine. I guess I need to get them checked out first before I can be sure that there is a problem.
 
#6 ·
UPDATE: I wasn't buying the mechanics diagnosis so I took it to the dealer. I asked "if a brake system flush would help?" They looked at it and came back to me and said that when the other guys replaced the brakes that they didn't machine the rotors and that is what it feels like when they don't do that. They said it is okay for now. I took it and used it last night and had to make a panic stop. They worked, but I'm still troubled by how far the pedal travels. I guess I need to go back and insist on a brake flush, except that I'm not even sure it will help. Hand Controls will be checked in 2 weeks but I am almost certain it is not a hand control issue. What to do?
 
#8 · (Edited)
Brake flush may not help nearly as much as freshly machined faces (more friction available) on your rotors. More friction between the pads and the rotors means shorter stopping distances, less pedal pressure required, hence less pedal travel. Have the pads replaced or atleast sanded at the same time. There could be, most likely is, a build-up of corrosion on the inside face of your rotors as well, which cuts down on the surface area availabe for effective pad contact when braking.
A brake flush is not even mentioned in your Owner Manual as being required so that says something about the need for it. However, it doesn't hurt to have fresh fluid every 60,000 miles or when you replace the calipers.
From afar, I think your problem is reduced brake effectiveness due to the rotors being too smooth and having a build-up of corrosion on the inner faces. I'm siding with the Dealer.

As to "flushing" of anything, here's what a Chrysler bulletin dated March 30, 2007 says:
Chrysler Group vehicle fluid systems do NOT require regular flushing. These systems include: engine oil, transmission oil, axle lube, brake fluid, power steering fluid, and
refrigerant. The only exception to this requirement are published in the vehicle maintenance schedules, e.g. engine coolant.
Exceptions to this recommendation include only those instances where a failure has occurred and/or the system has become compromised, contaminated or overheated beyond the normal operating range.

PS: New rotors may not be much more expensive than freshly machined old rotors, likely $20.00 to $30.00 a piece.
 
#9 ·
Brake flush may not help nearly as much as freshly machined faces (more friction available) on your rotors. More friction between the pads and the rotors means shorter stopping distances, less pedal pressure required, hence less pedal travel. Have the pads replaced or atleast sanded at the same time. There could be, most likely is, a build-up of corrosion on the inside face of your rotors as well, which cuts down on the surface area availabe for effective pad contact when braking.
A brake flush is not even mentioned in your Owner Manual as being required so that says something about the need for it. However, it doesn't hurt to have fresh fluid every 60,000 miles or when you replace the calipers.
From afar, I think your problem is reduced brake effectiveness due to the rotors being too smooth and having a build-up of corrosion on the inner faces. I'm siding with the Dealer.

As to "flushing" of anything, here's what a Chrysler bulletin dated March 30, 2007 says:



PS: New rotors may not be much more expensive than freshly machined old rotors, likely $20.00 to $30.00 a piece.

So what you're saying is I should get new rotors, or get these machined, right?
 
#7 ·
What kind of hand controls do you have. I am an amputee, but don't use them.

My buddy is a para and I have used his. The portable ones that don't have a permanent mount to the column are flimsy.

I don't think just replacing pads would cause excessive pedal travel. You might feel the braking surface, and get some noise, but no extra pedal travel.

Did the mechanic move your pedal mount? I have removed his when I borrowed the van, and I had to play with it when I reinstalled it (portable controls).
 
#13 ·
I find the inside face of the rotor, near the centre, can get a build up of scale that will wear a groove in the pads, making them less effective. I have often reused rotors, as is, when replacing pads but usually find that the glaze on the surface will eventually start putting grooves in the newer pads. For a better job, best to get the rotors machined or replaced at the same time.

Back in December, I replaced the OE rotors on an Acura after 80,000 kms. The bulid-up of scale on the inside face of those rotors was unbelieveable. The outside faces looked great. I was going to reuse the rotors until I got them off and saw that the inside face looked nothing like the outside face.
 
#14 · (Edited)
found out today that i need new brake shoes and wheel cylinders
 
#15 ·
I finally got the hand controls checked and it turns out the original mechanic was correct. After their check8up, the problem is gone! I had a hard time accepting it, but I guess I don't know as much as I thought I did.
 
#16 ·
Code:
The problem is most likely with rear caliper. I had changed the booster. Master cylinder. Abs pump. Nothing worked. When I changed the rear caliper the brakes became hard again. The emergency brake is built into the caliper. Sometimes this screws piston develops a problem. U can also check by pressing on the emergency brake. There should be no slack in it.
 
#17 ·
^^Please read a thread before responding to it, and take note of the dates. This was solved a long time ago, the hand controls were out of adjustment. Also, you are wrong about the rear brakes. You describe the 5th gen van rear brakes, and this is the 4th gen van section. Our parking brakes are "mini drums" inside of the rear rotors, so the regular and parking brakes are two entirely different systems (which I think is better).
 
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