Brake pedal goes to the floor intermittently

[mrbreezeet1]

Well, hopefully that fix's lt. Keep an eye on lt and let us know.

 

[wavinwayne]

Having experienced OP's situation in a couple of cars myself, my gut says the master cylinder will turn out to be bad.

 

[mrbreezeet1]

Having experienced OP's situation in a couple of cars myself, my gut says the master cylinder will turn out to be bad.

Yeah, the fluid change may have very well made it better, but could very well still need a master.
Time will tell.

 

[CARLOS DE LA CRUZ]

Having experienced OP's situation in a couple of cars myself, my gut says the master cylinder will turn out to be bad.

Well, yes, I will keep an eye on it, and if finally I need to do that I will let you know, I hope not to do it. Lol!

 

[CARLOS DE LA CRUZ]

Yeah, the fluid change may have very well made it better, but could very well still need a master.
Time will tell.

Yes, thanks guys, keep you post it. Regards

 

[Nukeman7]

Having experienced OP's situation in a couple of cars myself, my gut says the master cylinder will turn out to be bad.

Yeah, the fluid change may have very well made it better, but could very well still need a master.
Time will tell.

As I explained in Post #3, I also completely flushed the brake system twice in a month to see if it was trapped bubbles to no avail. Ultimately, replacing the master cylinder resolved the problem 100%.

 

[CARLOS DE LA CRUZ]

As I explained in Post #3, I also completely flushed the brake system twice in a month to see if it was trapped bubbles to no avail. Ultimately, replacing the master cylinder resolved the problem 100%.

Thanks

 

[CARLOS DE LA CRUZ]

Yeah, the fluid change may have very well made it better, but could very well still need a master.
Time will tell.

Hi Guys, well finally you were right on this. I changed my master cylinder. But I have a short story here, I don't want to sound like a fool, but this is my experience here. Also with this problem, the Sorento had bad bushing on the right side lower arm, and also the anti-roll bar bushing. It was causing strange moves when driving, if change the lane left to right, the steering wheel moves suddenly more to the same side and vice versa, during that time I notice the problem on my brake pedal, after 5 days of changing the brake fluid performed the same soft pedal problem once again, but only one more time. In the meantime the new master cylinder arrives, I decided to change all those bushing and working perfect that change, no more strange moves when driving, but also no more issues with the soft pedal. Even that because I was afraid to have an issue with a crash, I change the master cylinder when it arrived and perform the bleeding as I know and really I don't feel any change when I push the brake pedal, I mean it is working, but the feeling on pushing is the same as the old master cylinder and until now no issues with soft pedal. Do you think the suspension issues could cause something like this remotely? Just thinking a little bit crazy here! Well, also I took a picture from the booster inside and clean a little bit that. And never added new bake fluid when I got that problem. Thinking this old master cylinder just started with that problem and was the reason it was intermittent? Or remotely could happen the other I mentioned? Thanks

 

[John105]

So, no a problem with the ABS valves or something, right? Somebody told me maybe a relief valve could be damaged. Thanks

ABS should turn on a yellow warning and throw codes. But, it wouldn’t do what you’re experiencing. Believe it or not, at least in PA, a car can pass a safety inspection with a non working ABS system. But no red colored faults allowed.

I notice myself when ABS is not working, seems cars also disable traction and stability (prolly those systems rely on the ABS to work)

 

[Jetronic]

Hi guys I have a 2016 KIA Sorento 2WD EX and suddenly (only 3 times until now) brake pedal went to the floor and then recovery as normal. Do you think is with removing all the brake fluid and purge would work? Or maybe my master cylinder is damaged? Do you think I need to be worried about the ABS?
Thanks

That's a master cylinder issue

 

[Jetronic]

So, even I change new fluid it will be the same, because this looks old now and a little bit discoloration. Thanks

Old fluid can hasten the degradation of the seals in the MC, but changing the fluid now won't help.

 

[CARLOS DE LA CRUZ]

ABS should turn on a yellow warning and throw codes. But, it wouldn’t do what you’re experiencing. Believe it or not, at least in PA, a car can pass a safety inspection with a non working ABS system. But no red colored faults allowed.

I notice myself when ABS is not working, seems cars also disable traction and stability (prolly those systems rely on the ABS to work)

Ok, thanks, I already posted what I did finally before your comment.
Regards

 

[CARLOS DE LA CRUZ]

That's a master cylinder issue

Thanks I changed the MC finally!

 

[CARLOS DE LA CRUZ]

Old fluid can hasten the degradation of the seals in the MC, but changing the fluid now won't help.

Thanks

 

[burbguy82]

You are chasing a "leak". An internal leak really, the only thing it could be is at the master, ABS valves and maybe the booster if hydraulic.005% chance.

Good luck

 

[CARLOS DE LA CRUZ]

You are chasing a "leak". An internal leak really, the only thing it could be is at the master, ABS valves and maybe the booster if hydraulic.005% chance.

Good luck

Thanks my friend! That is what I heard! So, with the picture I got when I changed the new Master Cylinder, it looked like a very small leak behind the MC, I hope this is solved! If continue, hope not, I will assume it is an internal leak on the ABS valves. Booster is no hydraulic!

Regards

 

[burbguy82]

Thanks my friend! That is what I heard! So, with the picture I got when I changed the new Master Cylinder, it looked like a very small leak behind the MC, I hope this is solved! If continue, hope not, I will assume it is an internal leak on the ABS valves. Booster is no hydraulic!

Regards

I had a similar issue on an older vehicle I had years ago.....one of the most annoying until you know what is actually going on in the system. If you MC is new AND good, then I think you have fixed your issue. Have a good one.

 

[CARLOS DE LA CRUZ]

I had a similar issue on an older vehicle I had years ago.....one of the most annoying until you know what is actually going on in the system. If you MC is new AND good, then I think you have fixed your issue. Have a good one.

Please check 9 posts before this one, I attached the picture what I found after removing the old MC, tell me if you think it was an internal leak? Cause I never saw in the brake fluid container I needed to add, always was in the max line. Thanks

 

[Owen Lucas]

So, no a problem with the ABS valves or something, right? Somebody told me maybe a relief valve could be damaged. Thanks

I know of an issue with the second gen Ford Escapes where there was some type of issue, possible a software glitch that caused the brake pedal to drop to the floor randomly. Apparently there were multiple cases of this happening but the computer wouldn't record this error and there was no ABS light on. No TSB or update, so switching to a new ABS module could cause the same thing to happen. The problem was present on other Fords as well. Food for thought.

 

[burbguy82]

Please check 9 posts before this one, I attached the picture what I found after removing the old MC, tell me if you think it was an internal leak? Cause I never saw in the brake fluid container I needed to add, always was in the max line. Thanks

Well, I cant tell you much from the pictures as I am not an expert in your particular vehicle. But the little black "seal piece" looks suspect.

An internal leak would not manifest outside of the system, therefore no fluid would be needed to top off.

"leak" in this case, would be also described as "recirculation of fluid where the fliud can go, but is not supposed to go when the pedal is pressed"

Some systems, like the one I had, had a valve that allowed fluid to flow freely when the pedal was released. This valve was allowing fluid past the main pusher, and accumulating.

In a hydraulic system, a little fluid movement in the wrong area is plenty to kill the pedal. Hydrostatic pressure build and is released much faster than air pressure and there is much less room for error.