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Yes some are really spongy like my 01 4runner, everyone complains of the same thing, the brake pedal goes down proportionately thru 3/4 of the pedal travel then get firm and a solid push will brake to the ABS limit, so they work just feel like they go way down compared to other autos. Its a Feature!
 

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Discussion Starter · #22 ·
Yes some are really spongy like my 01 4runner, everyone complains of the same thing, the brake pedal goes down proportionately thru 3/4 of the pedal travel then get firm and a solid push will brake to the ABS limit, so they work just feel like they go way down compared to other autos. Its a Feature!
Good to know. Guess ill live with it! Thank you
 

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Hi everyone,

New member here. Bought a '15 Optima EX last month, new engine installed after failure!

I replaced all brake hoses, calipers, rotors, and pads. Bled all brakes according to the repair manual multiple times.

I noticed the brakes worked well but if I put a lot of pressure on the pedal it would slowly approach the floor.

After scouring the internet/youtube I found out a faulty master cylinder could be the issue.

I ordered a new master cylinder, and o-ring from the dealer. I got around to bleeding the master cylinder and all wheels again.

I must have bled the brakes 6 times by now. After researching I also discovered that there could be air trapped in the ABS module.

I've tried bleeding the 2 brake lines on the ABS module as well, after activating the ABS system by driving through leaves.

The pedal is still continuing to the floor after purposely pushing the down hard on the pedal.

Isn't the brake pedal supposed to stop about half way no matter how much force you put on the pedal?

This issue is driving me crazy because I've had to jack up the car multiple times now.

At this point i'm thinking the only thing I can do at this point is bring the car to a dealer/mechanic and have them bleed the system.

Just wondering if anyone might know what the issue is? there's no fluid leaking anywhere, and pretty sure air isnt being sucked in.

Thank you,
Evan
Bad master cly. replace it.
 

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Discussion Starter · #26 ·
The issue presented itself last wednesday.

As I was driving to a friends house my optima began hesitating on the highway. I pulled off into a shopping center and the front drivers wheel began emitting smoke.

I let it cool off before I began returning home. The caliper seemed to unstick for the ride home.

I immediately went to autozone for a new front caliper, and swapped out the old.

This solved my spongy, low brake pedal issue. I thought all was solved until the next day I was driving to my fathers house and yet again

the brakes began sticking again! This time it was both rear calipers, as I noticed they were crackling with heat. (cold that morning and rear brakes, so no smoke)

At this point I was beside myself as I kept having issues. I brought the car to a Kia dealer and explained all of the work that I had done to the car.

With "OEM" new rear calipers, front rotors and pads, front stabilizer bars are going bad, I was quoted ~$2160. LOL. With 3rd party parts $1500.

I was shocked to learn the rear calipers were both bad, and the drivers side rotor must've been warped.

After being quoted this price I decided to replace the rear calipers on my own AGAIN.

When I took the rear's off, both piston cups had a chunk missing out of the bottom! I swapped out the rears with good calipers from Car Quest.

As I was driving it home the front end being to vibrate. I guess I couldnt get away with the scoured rotor as it was shaking the whole front end even without the brakes applied.

The shaking was slightly worse when applying brakes.

I bought a new pair of rotors and pads. As I was replacing the drivers side I noticed the caliper piston boot appeared wet.

Mind you this was the "new" remanufactured caliper I had just bought from Autozone the previous day. I bled the brakes individually and low and behold there was a slow leak!

It dripped maybe 4 or 5 times. The cailper that I had just bought the day prior was bad again.

I called autozone and thankfully they were able to get me a replacement caliper at no charge.

After I replaced that caliper the car is stopping as if it were brand new! The pedal stops halfway like it should.

There is no such thing as "an aging vehicle's brakes wont perform like a new one!" This car is only 6 years old!

I will never buy brake parts off of RockAuto again! Even with their warranty I've had to claim a warranty on ALL their calipers.

After I got their replacement calipers they went bad AGAIN! I've had to replace calipers on this car 3 times for EACH wheel.

I thought the master cylinder was bad so I replaced that as well. I questioned if it was a bad ABS module, and tried bleeding that also.

Check your "NEW" calipers for leaks. I swore i didnt see any of my calipers leaking after I bled the brakes at least 10 times.

This was driving me nuts and hopefully this will save someone else headaches down the road.

I've never seen such bad quality control standards before. These calipers were trash, specifically mando, and other Rockauto brands. Complete trash.
 

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Discussion Starter · #28 ·
I finally found out what the problem is.

The brake booster push rod seems to be too long. Does anyone know how I can reduce the push rod length? I tried using pliers on the push rod but the nut wont turn.

I verified its the push rod length because I pulled out the master cylinder like 1/4 of an inch and the wheels began to spin freely on jack stands.

Please help! I dont want to ruin another set of calipers/pads and rotors.
 

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Discussion Starter · #29 ·
I figured it out. If anyone has this problem in the future.

Use a vice grip to hold the shimmed rod part and use a 7mm socket wrench to tighten the rod in order to shorten and loosen it to lengthen the rod if your pedal is going too low.

In my case the rod was too long causing brake drag.
 
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