My brakes are sticking

Tiny
MKLOSEK
  • MEMBER
  • 2010 HYUNDAI SONATA
  • 2.0L
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 159,000 MILES
Brakes are not releasing after removing my foot from the pedal. Repair shop diagnosed as bad front calipers. I changed calipers, pads and rotors but the issue persists. I replicated the issue with the front tires elevated. The wheels clearly lock-up after applying the brakes then would eventually release and rotate by hand.

There is feedback related to possibly being the brake light switch impeding the pedal from returning to it’s proper position, the rod from the pedal to the master cylinder being out of adjustment or petroleum in the brake fluid causing internal gaskets to swell.

None of these suggested root causes makes sense to me as the brake switch mechanism nor the rod have been to touched hence why would they be out of adjustment? The contamination of the brake fluid with a petroleum product is also questionable as what could be the source of the petroleum product contamination?

Any guidance will be greatly appreciated as all the mainstream repair shops want to do is continue replacing items as their primary method of diagnosing the issue.

Thank you,

MartyK
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Saturday, March 14th, 2020 AT 4:12 AM

42 Replies

Tiny
KASEKENNY
  • EXPERT
When you press the brake pedal and then release it, the pedal should immediately release and release pressure from the master cylinder which means the calipers will "spring" back and push the fluid back to the reservoir. If the calipers are not releasing then it is normally a caliper but if you have both front calipers doing it then more than likely it is something they have in common. So if they slowly release then that is because the fluid is being restricted from returning. This happens when the brake booster push rod is adjusted out too far which does no allow the brake master to return fully holding the brakes on. To confirm the issue loosen the brake master mounting bolts 3 turns to see if the car starts to roll again, if so remove the master and adjust the booster push rod inward.

First, press the brake pedal and watch to see if it is releasing or returning to the proper position or is it remaining low.

Unless the pedal is getting stuck on something (unlikely) then the most likely cause is the brake booster. Basically there is to be vacuum on both sides of the diaphragm but the air valve between the two sides sticks and holds pressure which doesn't allow the spring in the diaphragm to return the pedal to return. This holds the fluid in the calipers and doesn't allow the brakes to release.

Have you checked the rear brakes to see if they are holding as well? If it is just the front then the master cylinder is most likely the issue.

Let me know what you find and we can go from there. Thanks
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Saturday, March 14th, 2020 AT 7:58 AM
Tiny
MKLOSEK
  • MEMBER
Thank you for the feedback. The pedal returns to the top position without issue.

Just drove the car this morning and it was fine for the first 30 minutes/20 miles of start stop driving. Now the car stays in position when I release brakes at stop signs. Just jacked rear wheel and it is also hanging up.

It is odd to me that it took a some drive time for the issue to resurface but this is consistent with performance after I replaced the front brakes, calipers and rotors 3 days ago.

I really appreciate your insight while working through this issue. Thank you!
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Saturday, March 14th, 2020 AT 9:00 AM
Tiny
CARADIODOC
  • EXPERT
Hi guys. Please let me add a few comments of value, then I'll go sit in my corner.

If someone added brake fluid in between, it is going to run over and make a huge mess. That brake fluid eats paint too. If there is no obvious leak, low brake fluid level is an indication a brake system inspection is in order as part of regular maintenance, and expect to find the front disc brake pads need to be replaced. I'm sure some of these owners will share their complaint with anyone who will listen, and some of them will top off their own brake fluid. You have to wonder how many of them will unwittingly contaminate their brake systems, and if a problem develops, it is likely to become one of those "ever since" issues. "Ever since" that shop worked on my car, it has had this problem. The best we can do to prevent this is education.
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Saturday, March 14th, 2020 AT 2:48 PM
Tiny
MKLOSEK
  • MEMBER
CARADIODOC I truly appreciate the thoroughness of your response. Your feedback is that of what one may refer to as a subject matter expert.

The simplicity of the potential issue being related to the oxidation of the flexible line clamps is flooring to say the least.

Regarding the potential of petroleum contamination, I have a much better appreciation for the various ways contamination can occur. Thank you for the education!

The latest diagnosis provided by my mainstream repair facility of choice is the master cylinder. I will share my newly gained knowledge with them and with fingers crossed, we will resolve the issue.

Respectfully,

mklosek
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Saturday, March 14th, 2020 AT 4:12 PM
Tiny
KASEKENNY
  • EXPERT
Sounds great. Let us know. Thanks
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Saturday, March 14th, 2020 AT 7:16 PM
Tiny
MKLOSEK
  • MEMBER
The issue has raised its ugly head again following the replacement of the master cylinder. It has taken nearly a month to realize the master cylinder was not the issue due to limited use of the vehicle due to the pandemic lock-down.

After start stop driving for 30 minutes or so the brakes began to drag resulting in steering wheel shimmy, excessively hot front lug nuts, 3,000 rpm’s to accelerate to 40 mph and that awful burning brake pad smell.

Thoughts?
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Sunday, May 3rd, 2020 AT 7:24 AM
Tiny
KASEKENNY
  • EXPERT
We need to find out which wheels are doing it. I would suggest driving the vehicle to where it is acting up and then lift the vehicle and spin the wheels to see which one is grabbing. At that point we can test that leg of the system.

Let me know what questions you have and we can figure it out. Thanks
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Sunday, May 3rd, 2020 AT 9:55 AM
Tiny
MKLOSEK
  • MEMBER
Thank you for the reply KaseKenny1. I have dropped the vehicle off at my repair shop so cannot further diagnose. On the two previous occasions, the lockup appeared to be isolated to both front wheels as the rear wheels did spin free and the rear lug nuts were not hot like the front.
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Sunday, May 3rd, 2020 AT 1:37 PM
Tiny
KASEKENNY
  • EXPERT
Okay. That could be an issue with the proportioning valve. Basically this determines how much pressure to send to the front and rear brakes. It tries to keep the front or rear from locking up but it may be sending too much pressure to the front causing them to drag.

Keep us posted on what they find. Thanks.
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Sunday, May 3rd, 2020 AT 7:21 PM
Tiny
MKLOSEK
  • MEMBER
Good news folks! The issue has been resolved with the replacement of the flexible front brake lines. I truly appreciate all of the support CARADIODOC and KASEKENNY1.
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Friday, May 22nd, 2020 AT 5:08 AM
Tiny
CARADIODOC
  • EXPERT
Dandy. Happy to hear you solved it.
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Friday, May 22nd, 2020 AT 6:47 PM
Tiny
JSUT56210
  • MEMBER
  • 2006 HYUNDAI SONATA
  • 3.3L
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 68,000 MILES
Only happens sometimes, but if I come to a complete stop and release the pedal the brakes lock then slowly release. Any idea what is wrong? Also, the ESC light came on but eventually went off.
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Monday, March 15th, 2021 AT 6:05 PM (Merged)
Tiny
STEVE W.
  • EXPERT
Can you tell if it's front or rear OR all 4?

As the ESC light came on it should have stored a code but you need a factory grade scan tool to read them, the free scans only cover the engine codes. If you can get the codes it would make it easier. Without them the below are the likely culprits.

The description sounds like you have a sticking caliper piston. That could be due to uneven pad wear that twists the caliper. Checking requires removal of the wheel/tire and visual inspection of the pads and rotors to see if they are worn uneven.

It could also be a failing flexible brake line. They can fail inside and act like a one way valve. You apply the brakes and the fluid either cannot return or returns very slowly.
These can be hard to find if it only happens once in a while because they will look fine on the outside. Sometimes you can find them if you jack up the vehicle and stomp the brake and have someone immediately try to spin the wheel by hand as soon as your foot is off the pedal. If the wheel is hard to turn and slowly gets easier I would suspect the line.

If it's all 4 I would look at the master cylinder and the ABS module, after getting the codes.
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Monday, March 15th, 2021 AT 6:05 PM (Merged)
Tiny
LISA1515
  • MEMBER
  • 2005 HYUNDAI SONATA
  • 52,000 MILES
Put new breaks and master cylinder in no leaks
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Monday, March 15th, 2021 AT 6:05 PM (Merged)
Tiny
CARADIODOC
  • EXPERT
Brake fluid is trapped and can't get back to the master cylinder. When it happens again, loosen the mounting bolts for the master cylinder. If the brakes release, check the push rod to see if it's over-adjusted, or if the brake light switch is misadjusted and holding the brake pedal down. If they don't release, open the bleeder screws at the front calipers. If the brakes release there, check the rubber flex hoses.

Why did you replace the master cylinder? Any chance the fluid is contaminated with petroleum product?
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Monday, March 15th, 2021 AT 6:05 PM (Merged)
Tiny
LISA1515
  • MEMBER
This happened 3 months ago and the mechanic put master cylinder in it was fine for 3 months nows it started again this week
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Monday, March 15th, 2021 AT 6:05 PM (Merged)
Tiny
CARADIODOC
  • EXPERT
The first thing to check is the rubber bladder seal under the reservoir cap. If it's blown up and mushy, there' a petroleum-based contaminant in the brake fluid. The only proper repair for that is to replace every part in the hydraulic system that contains rubber parts that contacts the brake fluid, and all steel lines must be flushed and dried.

At 52,000 miles and six years old, it's very unlikely the master cylinder failed on its own. If it failed due to fluid contamination, that contamination will leach back out of other seals and hoses and recontaminate the new master cylinder. That typically takes a few weeks to a couple of months.

The way to prove or disprove this is to loosen the steel lines right at the master cylinder while the brakes are locked up. If they release, fluid contamination is the chief suspect. The misadjusted push rod or brake light switch that I mentioned previously wouldn't be okay for three months, then suddenly start causing a problem.
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Monday, March 15th, 2021 AT 6:05 PM (Merged)
Tiny
DAVIDZARATE
  • MEMBER
  • 2005 HYUNDAI SONATA
  • 4 CYL
  • 65,336 MILES
I have an 6/04 hyundai sonata and have replaced the rear pads rear rotors, rear calipers front and rear brk hoses, fluid, and while driving the front and rear brks start locking up
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Monday, March 15th, 2021 AT 6:05 PM (Merged)
Tiny
NICKB275
  • MEMBER
Please be more specific, does it feel like ABS braking or a complete brake lock-up, such as all four wheels locking up and staying applied and not releasing. Does the ABS light flash when this happens? Did you have any problems of note when changing the brakes? Did everything install back into place with no problems?
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Monday, March 15th, 2021 AT 6:05 PM (Merged)
Tiny
DAVIDZARATE
  • MEMBER
All four complete brake lock-up and does not release until resting for approx. 1 hour. And yes the abs light is on
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Monday, March 15th, 2021 AT 6:05 PM (Merged)

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