First off, I have a 2004 V8 sport/premium with 36k and no mods whatsoever. 99% of the time, the brake pedal has a nice smooth feel to it and the car stops just fine. That other 1%, the brake pedal feels extremely "crunchy" and the pedal itself makes a grinding noise when depressed. The car still stops, but it almost feels like it takes more pressure on the pedal to do so. Any ideas? I know the throttle is by wire, are the brakes too?
"crunchy" brake pedal....
- Thread starter moundtown
- Start date
The brakes are not by wire. They are hydraulic with vacuum assistance. Are you sure its not just the ABS cycling? When the ABS cycles a pulsation and 'chatter' can be felt through the brake pedal. ABS will cycle if braking is done on a slippery surface or occasionally when on rough terrain. Type BRAKES in the search function for more info. Hope this helps! 
Thanks for the reply. It does it when on completely even, smooth pavement, so if it is the ABS cycling, it is doing it at improper times. I searched and didn't come up with anything similar to my symptoms.....
Hmmnnn... All the cars i have owned which had ABS would cycle very occasionally for no apparent reason so maybe its normal??? Usually, if there is a fault with the ABS a code will be stored and the amber light will illuminate. Hopefully some of the LS guys can give you more info.
eL eS
Dedicated LVC Member
I had a similar problem with my 03. I took it in and they diagnosed it as a problem with the master cylinder and was covered under warranty.
glanga
Dedicated LVC Member
did you try checking to see if you need new brakes????
Bodyshield
Active LVC Member
+1 I want info on this, dad drove it and talked about the weird feel on the pedal, so I'm going to take it in and see whats the deal
MDavis0424
Active LVC Member
Post what happens. I had the front brakes replaced a couple of weeks ago, then last week I had the same thing happen a couple of times. It feels a lot like when the ABS kicks in, but it's in the first half inch of pedal travel before the brakes start slowing the car down, you can even hear a little bit of a crunching sound coming from the pedal assembly itself. It did it 5 or 6 times over a two day period, but hasn't happened since.
Yes, mine is intermittent also. I will drive it for several days without a problem, then bam, it starts doing it again. I checked the rotors/pads at all four corners, and nothing out of the ordinary.......since I am apparently not the only one experiencing this problem, why is it not more widely known?
wildstang607
Active LVC Member
does anyone know what the crunch is for sure. my 2000 just started doing this. i just had a new engine put in at the ford dealer. they say it is nothing to do with them, but it never happened before. its a bad vibration sound from the engine bay when i'm on the brakes.
rickztahone
Dedicated LVC Member
wildstang607
Active LVC Member
i call it new, but it's a used 40,000 mile engine. with the cost of the engine it was $2422. not bad, but i wish it wasn't my daily driver i'd have put in a windsor with a carb.
Husker Z
Well-Known LVC Member
Mine does this too, exactly, very intermittent, which is good, but I'd like to know what it is. Let us know when you find out.
stuntin_LS
Well-Known LVC Member
my 02 malibu and my 04 lincoln both did this... i got sick of it in the lincoln and had the brakes checked several times and they stopped most of the squeaking and even the crunch
owlman
Dedicated LVC Member
Mine felt crunchy today, very odd. Then when I parked the pedal went to the floor. Driving it a few hours later it was back to normal. wtf? I'll take it to the dealer (warranty) and let you know what they say...
Apathy25TX
Active LVC Member
I had the same issue on mine, but mine was a little more serious since I thought it was a rotor issue. What mine turned out to be was the front wheel bearing giving way. The rotor would make contact with the caliper ( the crunchy sound ) due to the play of the worn out bearings. It ground the shyte out of my rotor. If your rotors have big time wear on 'em, you may want to check out the bearing.
owlman
Dedicated LVC Member
+1 I finally took mine in for this crunchy brake pedal feel/sound. Same diagnosis except they also replaced the brake booster.
lls05
New LVC Member
brakes
i talked to the dealer few months ago about this brake issue i am having with my 2005 Lincoln LS dating back to last year when they check them and replaced the booster under the factory warranty. the mechanic took it home with him and said there's nothing you can do about the noise. So I have been doing some research and found out that this "crunching sound" from the pedal/brakes is fairly common. Several people who i spoke to told me that they have the same problem and had the master cylinder and the brake booster replaced and that worked. If the car sits over night then you drive it the brakes work fine, 15-20 min into the drive the brakes make that noise and they are getting worse. The vehicle does not stop as it should when the noise is present also if you are at a light an the brake pedal is applied it will slowly drop closer to the floor. This is a email i sent to the dealer, can you tell me if you were having the same problems and replacing the booster and master cylinder did that work?
Thanks, Dan
dupd120@yahoo.com
i talked to the dealer few months ago about this brake issue i am having with my 2005 Lincoln LS dating back to last year when they check them and replaced the booster under the factory warranty. the mechanic took it home with him and said there's nothing you can do about the noise. So I have been doing some research and found out that this "crunching sound" from the pedal/brakes is fairly common. Several people who i spoke to told me that they have the same problem and had the master cylinder and the brake booster replaced and that worked. If the car sits over night then you drive it the brakes work fine, 15-20 min into the drive the brakes make that noise and they are getting worse. The vehicle does not stop as it should when the noise is present also if you are at a light an the brake pedal is applied it will slowly drop closer to the floor. This is a email i sent to the dealer, can you tell me if you were having the same problems and replacing the booster and master cylinder did that work?
Thanks, Dan
dupd120@yahoo.com
owlman
Dedicated LVC Member
Sorry, I just noticed your reply now. Mine only started to make the noise after about an hour of driving, especially city driving, not 15-20 min like you say. Anyway I have had no problems since they replaced my master cylinder and booster. No more crunchy pedal feel or noise ever.
LS Chazzy J
LVC Member
This thread is old, and I'm new, but I do know a little bit about this problem. So I'll add information since this is an incredibly common problem with Ford Master Cylinders. More so recently than anything.
What happens is people neglect the brake fluid and leave it in there way past its regular life cycle. I recommend having your brake fluid changed out every 25,000-30,000 miles. It can notably go much longer than that, and in some cases people still have their orginal brake fluid from the day it was driven off the lot (yikes!). However, because these master cylinders are so touchy, I would say get it changed out every 30K atleast.
When changing this out, go to a local auto place that does it properly. They have a pump they put on top of the master cylinder that will remove the old fluid and put in new fluid. There is another way to do this with you and your friend in the comfort of your own garage which is known as the "brake pedal" method which involves you using release valves on the brake calipers and then "pumping" the new fluid in by pressing the brake pedal many times. I do not recommend this due the stress it puts on the master cylinder seals (read next paragraph).
What is the problem with the master cylinder specifically? I saw someone ask this question. Well there are two seals in the master cylinder. One of which sends brake fluid to the front brakes, another of which sends brake fluid to the rear brakes. Everytime you press your brake pedal it is attached to a rod in your brake booster. That rod goes into your master cylinder. The forward movement of this rod moves your seals in the master cylinder allowing the system to move more brake fluid to your brakes, hence applying the brakes and causing the car to stop. These seals typically only have about 1/2 an inch of movement in them. However, as previously stated, the brake pedal has more travel and a "crunchy" feel to it. This is because these seals have begun to go bad due to bad brake fluid. The brake fluid acts as a lubricant for these seals as well, when the fluid breaks down it causes irregular wear on the seals. Over time, they go bad.
It should be noted that when you use the "brake pedal" method to re-bleed your brake lines, it causes excess travel on the seals inside the master cylinder. While on a healthy master cylinder this will not cause long term damage, on a unhealthy master cylinder (ours) it most certainly will. Have the new brake fluid put into the system via master cylinder pump.
The remedies to our "crunchy" brake pedal problem: Well, mine only acted up once in a blue moon. Typically after I had run errands all day and I was in a parking lot or slow city driving. However, once on the highway, the brake pedal would act normal when getting off on an offramp. However, once I returned to slow stop and go driving or a parking lot, it would act up. Once it sat overnight, it would be back to normal until my next long day of errands. Well I started with the cheap fix -- I went to sears auto (yikes! I know) and told them I wanted a brake fluid flushed and replaced with new fluid. They did it, successfully I might add, and to this day I have not had the "crunchy" brake pedal problem. Some of you have this problem much more than "once in a blue moon." In which case, a simple fluid switch may not solve the problem for you. You may be required to switch out the master cylinder. With this in mind, don't worry about the brake booster, there is nothing wrong with it. The sound and feel of the brake pedal has to do with your seals going bad and extending further beyond the point of travel than they should.
Hopefully this post will serve as a good source of information since these cars are getting older and this problem is probably becoming more rampant.
Thank you,
CJ
What happens is people neglect the brake fluid and leave it in there way past its regular life cycle. I recommend having your brake fluid changed out every 25,000-30,000 miles. It can notably go much longer than that, and in some cases people still have their orginal brake fluid from the day it was driven off the lot (yikes!). However, because these master cylinders are so touchy, I would say get it changed out every 30K atleast.
When changing this out, go to a local auto place that does it properly. They have a pump they put on top of the master cylinder that will remove the old fluid and put in new fluid. There is another way to do this with you and your friend in the comfort of your own garage which is known as the "brake pedal" method which involves you using release valves on the brake calipers and then "pumping" the new fluid in by pressing the brake pedal many times. I do not recommend this due the stress it puts on the master cylinder seals (read next paragraph).
What is the problem with the master cylinder specifically? I saw someone ask this question. Well there are two seals in the master cylinder. One of which sends brake fluid to the front brakes, another of which sends brake fluid to the rear brakes. Everytime you press your brake pedal it is attached to a rod in your brake booster. That rod goes into your master cylinder. The forward movement of this rod moves your seals in the master cylinder allowing the system to move more brake fluid to your brakes, hence applying the brakes and causing the car to stop. These seals typically only have about 1/2 an inch of movement in them. However, as previously stated, the brake pedal has more travel and a "crunchy" feel to it. This is because these seals have begun to go bad due to bad brake fluid. The brake fluid acts as a lubricant for these seals as well, when the fluid breaks down it causes irregular wear on the seals. Over time, they go bad.
It should be noted that when you use the "brake pedal" method to re-bleed your brake lines, it causes excess travel on the seals inside the master cylinder. While on a healthy master cylinder this will not cause long term damage, on a unhealthy master cylinder (ours) it most certainly will. Have the new brake fluid put into the system via master cylinder pump.
The remedies to our "crunchy" brake pedal problem: Well, mine only acted up once in a blue moon. Typically after I had run errands all day and I was in a parking lot or slow city driving. However, once on the highway, the brake pedal would act normal when getting off on an offramp. However, once I returned to slow stop and go driving or a parking lot, it would act up. Once it sat overnight, it would be back to normal until my next long day of errands. Well I started with the cheap fix -- I went to sears auto (yikes! I know) and told them I wanted a brake fluid flushed and replaced with new fluid. They did it, successfully I might add, and to this day I have not had the "crunchy" brake pedal problem. Some of you have this problem much more than "once in a blue moon." In which case, a simple fluid switch may not solve the problem for you. You may be required to switch out the master cylinder. With this in mind, don't worry about the brake booster, there is nothing wrong with it. The sound and feel of the brake pedal has to do with your seals going bad and extending further beyond the point of travel than they should.
Hopefully this post will serve as a good source of information since these cars are getting older and this problem is probably becoming more rampant.
Thank you,
CJ
hotrod03lincolnlsV8
LVC Member
Roll down the window and listen-
I have experienced the same "crunchy" pedal feelings and noises, at one time the noise was from "inside" the car and I could certainly feel the noises in the pedal. I have not experienced this in a very long time- though I have made it a point to remove the brake fluid from the reservoir and replace it with fresh. This might account for the initial noise disappearing...
The most recent brake noises are coming from outside the car, more specifically the front brakes. I have replaced all the pads and rotors a while back and I then noticed some of the noises. The front aluminum brake calipers actually stretch/expand/flex when applying significant braking pressure allowing the pads to slip or chatter. The pads shift, albeit a very small amount (fractions of an inch) but when they do move, braking force is reduced for that split second. With the sudden shift of the pads a bang/snap is noticed, as well as a slight amount of pedal travel; it is most noticeable when the brakes are warm/hot.
I have not investigated this further; however the problem seems to be amplified when high performance/hard compound pads are used-- thus requiring more pressure to stop. I do not know if this is experienced by many, however I have seen this on my 03 for better than 30k miles. This might account for some of the braking noises we are experiencing.
I have experienced the same "crunchy" pedal feelings and noises, at one time the noise was from "inside" the car and I could certainly feel the noises in the pedal. I have not experienced this in a very long time- though I have made it a point to remove the brake fluid from the reservoir and replace it with fresh. This might account for the initial noise disappearing...
The most recent brake noises are coming from outside the car, more specifically the front brakes. I have replaced all the pads and rotors a while back and I then noticed some of the noises. The front aluminum brake calipers actually stretch/expand/flex when applying significant braking pressure allowing the pads to slip or chatter. The pads shift, albeit a very small amount (fractions of an inch) but when they do move, braking force is reduced for that split second. With the sudden shift of the pads a bang/snap is noticed, as well as a slight amount of pedal travel; it is most noticeable when the brakes are warm/hot.
I have not investigated this further; however the problem seems to be amplified when high performance/hard compound pads are used-- thus requiring more pressure to stop. I do not know if this is experienced by many, however I have seen this on my 03 for better than 30k miles. This might account for some of the braking noises we are experiencing.
I also recommend changing brake fluid. I do this on my 2003 LS about every 30K miles. I always use the pedal pump method. It gives a very thorough flush. I also have a power brake bleeder but it does not seem to do as good a job? Never had a master cylinder problem but the car is only at 78K miles now. I am always amazed at how dirty the fluid that comes out is!!!
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Tony Starks
Well-Known LVC Member
i am having the same problem but this only started recently when
im driving in snow..very wierd.. but when im driving on dry or wet (rain) roads
it doesnt happen.. its happened twice
im driving in snow..very wierd.. but when im driving on dry or wet (rain) roads
it doesnt happen.. its happened twice