01 Kia Sephia brakes

Maintenance/Repairs
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1

2001 Kia Sephia, 1.8L, ~122K miles, regular services are all being done. Automatic, also serviced per schedule.

Brakes pedal would depress further and further until it hit the floor.

23 Mar, 2010: Taken to Just Brakes. New pads and shoes, turned rotors and drums, rear wheel cylinders (new, due to leaking), purged system, new fluid.

Two weeks later, more pedal fade…to the floor. Back to Just Brakes, bled system. Operated correctly until April.

23 Apr 2010: Independent Mechanic (Brake Check employee, ASE certified, works on the side) Cause: brake Fade. Resolution: Brake Master Cylinder replaced with one from Advanced, make Cardon. When removed, was “damp” behind it, but not a noticeable leak. System bled again, operated normally.

Jul/Aug 2010: Brake check again. Complaint: Pedal fade again. Resolution: Replaced rear wheel cylinders with another manufacturer. Bled system again.

Dec 2010: Pedal fade again.

Now the car is sitting because the driver (older woman) feels it is unsafe. She also transports kids (5 & 7) back and forth to school, and the last time it faded badly, she was in traffic, with the kids. The emergency brake worked, so she finished that trip. The car is a couple hundred miles away from me all the time, so I almost never get to see it. I’m just trying to help out a workmate who sees his wife only on weekends, as he lives/works in 2 different cities.

So…any thoughts on what might be wrong with this? Master, rears, shoes, pads and fluid are new, there are no discernible leaks, and a system bleed will return them to operating correctly for a couple weeks to a couple months, then they start to fade again.

Chase

2 
I hope this is not a duplicate message.  Something screwy happened when I tried to respond the first time.<div><br></div><div>    <span class="Apple-style-span" style="font-family: Arial, Helvetica, sans-serif; line-height: 18px; "><b><i>Now the car is sitting because the driver (older woman) feels it is unsafe</i></b>   </span></div><div><span class="Apple-style-span" style="font-family: Arial, Helvetica, sans-serif; line-height: 18px; "><br></span></div><div><span class="Apple-style-span" style="font-family: Arial, Helvetica, sans-serif; line-height: 18px; ">    She is smart.  </span></div><div><span class="Apple-style-span" style="font-family: Arial, Helvetica, sans-serif; line-height: 18px; "><br></span></div><div><span class="Apple-style-span" style="font-family: Arial, Helvetica, sans-serif; line-height: 18px; ">    I suspect a leak in a fitting or a brake line somewhere.  Do they make a UV dye for brake fluid?  Maybe that would help find the problem.  </span></div>
3

My friend has yet to put any fluid in - it doesn’t seem to be leaking anywhere.

One thought I had was that they may have used Dot4, when it calls for Dot3. I know Dot5 can impact the system, but can Dot4 in a Dot3 system?

He gets very little time to work on it, and as she has an Exploder at her disposal, she doesn’t push, and he can take the time…I can’t come up with anything else. The folks at just Brakes (I know, stupid chain) do nothing but bleed the system again. So it sounds like somehow, air is being forced into the system, but I can’t figure out how.

When he replaced the master, he used the reservoir from the original…but that’s only a piece of plastic, so it should be OK.

The flush was a forced air flush, with a unit they mounted on the master, and bled the lines, one at a time to clear the system.

Chase

4

No Sticking Calipers / Cylinders Or Dragging Brakes That Would Gradually Boil The Fluid, Eh ?

CSA

5

Honestly, I don’t know. I can check into it, though. I’ll dig into the paperwork when I see him tomorrow and see what it says. As far as I know, no, but … I don’t know. There could be a sticking one…or two.

Thanks, CSA…that’s 1…

6

The problem might be with the caliper piston seals.

I've seen cases where the caliper piston seals don't allow brake fluid to escape when the brakes are applied, but when the brakes are released and the pistons draw back slightly into the caliper bores it pulls a slight amount of air past the seals. This air accumulates in the calipers over time and while doing so the brake pedal slowly gets closer to the floor until there's no hydraulic pressure. Once the brakes are bled again the hydraulic pressure returns.

Tester

7

That fits the description perfectly. I’ll pass these on to him tomorrow. When he heads “home” this weekend, I’ll have him drive it for a while, and see if one of the front wheels is getting very hot or not, and also ask him to pull the calipers, and bring them to me for rebuild.

(I just really don’t want him or her driving the car here, and I don’t want to try and tote everything I’ll need up there). He has quite a few very, very quiet roads he can tackle.

Thanks, guys.
Chase

8

Check that the star wheels haven’t inadvertently been swapped from side to side or installed on the wrong side if hardware was replaced. That will mare the rear shoes loosen instead of adjusting and drop the pedal.

9

Thanks…will pass that on, too. But they haven’t gone back into the system, only bled it to restore function, so it’s unlikely, but definitely worth a shot.

I was also told a horror story about this place…when he took it back to get it working the third time, when they swapped the rear cylinders, the shop foreman got the wrong parts. Didn’t fit in the backing plate. So he started hammering at them with a 3Lb hammer. My buddy knew (of course) his wife’s care was there, heard the noise, and wandered around to see what they were hammering on. Once he saw it was his car, he kinda had a fit…deservingly, and then, rather than get the right part, this guy took it to the bench for some vise and file work! Had to make it fit. So my buddy continued with his rant, made them get the correct parts and once back together, hasn’t gone back. So that’s why this problem isn’t going back to them.

Most of the work he can do, but brakes are a safety issue, and he just wanted it done right. Now he only wants it to work. :slight_smile:

Chase

10

Over the past year I’ve dealt with a Spectra that had multiple brake failure issues. All of the hydraulic parts except for lines and proportioning valve have failed and once I even found the parking brake cable to be severely overtightened. I’ve seen many brake problems with this car and can see which are likely to cause your symptoms. This is what I think you should do:

First, I am going to assume you haven’t been seeing an excessive fluid level drop in the brake fluid reservoir. If you have, then you’ve got an easy to find leak.

Note that where I say to replace a component which is rebuildable, rebuilding is fine. After any replacement or rebuild of component, start this check again at the top. Let’s fix this thing before anybody gets hurt.

-Verify that no wiring (such as for after-market equipment) or floor mat limits upward travel of the brake pedal. Correct any problem found.

-Bleed the brakes. I understand that you’ve already done this but do it again. Do not use a pressure or vacuum bleeder, do it the old fashioned way. Open valve, pedal down, close valve, pedal up. No pumping. Always bleed with the reservoir cap loosened 1/4 to 1/2 turn. If you cannot get five consecutive squirts with good strong flow and no air at any one wheel, replace the caliper or wheel cylinder at that wheel and bleed again. If you cannot get five consecutive squirts with good strong flow and no air at two or four wheels (not one or three) replace the master cylinder, reservoir, and the rubber grommets where they meet, then bleed again.

-Wait 30 minutes, then bleed the same way again. If any air at all is present at one wheel replace the caliper or wheel cylinder at that wheel and bleed again.

-For each caliper:
Remove the caliper without disconnecting the hose. Use plastic (not metal!) hose clamping pliers to pinch off the brake hose. Using a suitable tool (be creative if you have to) grasp the caliper piston and try to pull it out from its bore. Pull for a minimum of 30 seconds. Put the caliper back into place, remove the hose clamping pliers, and bleed at that wheel. If any air is present, replace the caliper and bleed again.

-For each wheel cylinder, check for any wetness or corroded metal behind the dust boot. Check that the pistons move freely in and out (one moves in as the other moves out) with no roughness or binding. If any wetness, corrosion, roughness, or binding is found, replace the cylinder and bleed the brakes.

-Remove the brake fluid reservoir cap. Check that the rubber diaphragm is properly seated on the reservoir fill opening, is not swollen or oily feeling, and has no punctures or tears. Replace it if otherwise. If oily feeling, first thoroughly flush the brake fluid out with new fluid, then replace all calipers, wheel cylinders, and hoses, as well as the master cylinder, then bleed thoroughly.

-Note the hole on the outside of the reservoir cap. Verify that you can easily blow air through the hole. Insert a small tool into the hole from the outside, and verify that you can see the tool from the bottom side of the cap. If you cannot blow through the hole or cannot see your tool, repair or replace the cap as needed then bleed the brakes. I mean that. Bleeding the brakes is necessary if the vent hole in the reservoir cap has been found to be clogged.

-Check the length of the adjustable push-rod between the master cylinder and the vacuum assist booster. Verify that it does not turn (adjust) too easily. If it adjusts too easily, deform the threads slightly so that it does not, then adjust correctly. If it is too long, first adjust correctly, then bleed the brakes.

If you skipped part of this because it didn’t make sense or looks like a waste of time, start over at the beginning. My wording may not be the best, but there are NO extra steps laid out in this plan. All of it is necessary. Do not assume that finding and correcting one problem will fix it. When dealing with a problem car, just when you think it is fixed is the time you need to start checking everything from the beginning.

Hopefully the problem is fixed at this time. It would be good to use the car for a bit and make sure there is no sign of any problem recurring before returning it to its owner.

11

Thanks for the response. I realize it’s been ages since the original post, but again, it’s not my car.

The master cylinder was working properly. There was no excessive play in any of the components.

My co-worker finally got the parts, and brought the car down. We rebuilt the front calipers a couple weeks ago. He has since returned the car to his wife, but I haven’t heard good nor bad yet.

It’s important to note that the passenger side caliper was almost empty of brake fluid, took quite a few pumps of the brakes to force the piston out, and the fluid that DID come out was rusty. We cleaned everything up, changed the fluid, and are waiting to see if it’s fixed, or if the car exhibits more symptoms. I think it’s OK, but only time will tell. I’ll post back when/if I hear anything back.

12

Hello, again, guys (and gals, where appropriate).

I’ve finally heard back about the condition of this thing (I know, right?). He had to bleed the brakes again to restore normal operation.

He finally revealed (after about 6 months now), that his wife RIDES THE BRAKES! I’ve tried to explain (and he has done the same to her) how dangerous this can be…brake fluid boiling, lights on all the time, people having no clue what you’re doing until they hit you, etc. She still rides them. She’s almost 60 now, and while I think the keys should be taken away if she can’t learn to drive correctly, that would leave her stranded for days at a time.

If anyone has any suggestions to reduce the amount of fluid boiling (at this point, it’s my only guess: there is no leaking going on), I’m all ears. Other than that, this thread can be closed. Can we put Dot4 or even Dot5 in there? Would it even help?

Thanks for all the great ideas, guys.

Chase

13

Did you ever get the brake proportioning valve checked out because on my 2001 Kia Sephia I had an issue with brake pedal going to floor and it was my break proportioning valve