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Kia Sephia Weak Brakes ~ Solved the Mystery!

63K views 69 replies 6 participants last post by  Loyale 2.7 Turbo 
#1 ·
There is a Fact: The Second Gen (1998~2001) Kia Sephia (Like my Wife's Model) has Weak Brakes and Suffers from Premature front Brake Wear. I Noticed the Weak Brakes since we obtained the Car.

I investigated further on the Subject on Internet and I Found that the Problem was so generalized that it ended in the Court, with Lawsuits against Kia, in some cities of USA.

I'm Lawyer, so I spent Hours and Hours Reading Documentation on-line, Such Like the Following:
(Each one is a clickable a Link to a Website)

"Judge Certifies Class Action Suit for Kia Sephia Owners"

"KIA SEPHIA BRAKE PROBLEMS AND CLASS ACTION"

"New Jersey's Court Desicions in the Subject"


Could you Believe that there are some Websites entirely dedicated to that issue?

"Facebook Page for the Sephia's Defective Brakes"

http://kiasephiadefectivebrakes.com/

Well, some of the Lawsuits says: (Source: Kia Sephia Brake Defects Promote Class Action Lawsuits in PA and NJ)

Consumers Suffer Brake Defects in 1998, 1999, 2000 Kia Sephias; Class Action Suits Filed in Pennsylvania and New Jersey, More than 166,000 Automobiles Could Be Affected
So, the Problem is a Fact that I Needed to Solve ASAP, but after Weeks Reading many Documents, seems like no one found the Answer of "Why" that Happens and "How" to fix that problem; they only talk about the weakness of the Brakes and the Front Rotors' Warp plus premature wear.
 
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#40 ·
Mystery and Problems: Completely Resolved!

Enough time has passed since the Rear Disc Brakes' Swap and after some Highway Travels and many city daily driving, including some unintentional Panic Braking to avoid accidents; I could assure that the "KiaStein" featuring all the Brake parts updated as I explained in previous posts of this Thread, now has an Outstanding braking Behaviour, using way less Space to Stop, and Without Lockin' the Wheels too Hard.

As I explained, the car needed these parts:

Improved "Groveless" Proportioning Valves.
to avoid air getting onto the system / leaking brake fluid.

Increased Bore Master Cylinder + Dual Diaphragm Booster.
to solve the "Deep Traveling" brake pedal, which goes even Deeper with Rear Disc Brakes, due to the increased Brake Fluid Chamber on the Calipers.

Rear Disc Brakes.
to get rid from the noisy rear drums and their useless self adjusters, that lead the drums to do almost nothing, letting the front discs to bear almost alone with the vehicle's braking, with the consequent premature wear / warp of the front brakes.


Unlike the useless rear drum brakes, the Rear Disc Brakes' setup on these Sephias is Awesome; the only drawback is that the Parking Brake on the Drums is Stronger than the Parking Brake on the Discs. After the install I also cleansed and painted the front Calipers with same High Temp anti-rust ceramic paint; let me share a couple of Photos:

The Front Calipers:



(By the Way, here you can see the '03 Spectra T8D engine)



the Rear Calipers:



So now I can Assure that the Weak Brakes problem on my Wife's Kia Sephia, the "KiaStein" has been completely Solved, and if you review carefully this thread, you'll notice that the Kia Engineers did almost the same upgrades I did, on their Sephias that featured Rear Disc Brakes from Factory.

Disclaimer: Use all the information I post, at your own Risk.

Kind Regards.
 
#41 ·
A couple of additional issues

The Brakes on the "KiaStein" has been working very very well, with the proper 15/16" master cylinder + Dual Diaphragm Booster, and the Four Disc Brakes; however I noticed a couple of minor issues; both of them are related to Specific Circumstances.

The first issue: Driving on the Caribbean Hot Climate with A/C on, for prolonged periods of time, is a situacion that always trigger an issue: The brake pedal becomes Spongy and the Braking Power were Reduced in certain amount. Since the issue became even Worse after driving on same circumstances but during Traffic Jams, it was related with the amount of Heat on the engine bay for sure.

So, after investigating and doing some tests, I found that the Master Cylinder gets extremely Hot during such driving circumstances, in fact, it Burnt a little the skin of my Hand by just Touching it, after an Hour of being driving under direct Caribbean Sun Light, on Traffic Jams with Air Conditioner at Maximum settings.

I noticed what could be considered as a major design flaw on certain cars: The arrangement and disposition of the things on the Engine Bay, makes some sort of Tunnel, that directs almost all the hot air flow that is being expelled from the Main Fan at the Radiator, and also by the Auxiliary Fan for the A/C system, almost directly to blow over the Master Cylinder.

Any Master Cylinder itself normally gets Hot during regular use, because the Brake Pads gets Hot and such heat is transmitted by the Brake Fluid; so the Master Cylinder has to Bear with that inner temperature, and also usually has to bear with the Outer temperature from the Hot air flow, coming from the Main Fan at the Radiator, but such fan is intermitent and usually doesn't come On too often during Highway Drivings, the problem usually goes unnoticed.

So, the source of the issue, is the Second Fan for the A/C which together with the Radiator fan at non-stop working, blows an increased amount of hot air to the Master Cylinder which gets heated like a Forge, creating some sort of Smithy effect on its bare metal.
 
#42 ·
ideas & solutions

I Kindly suggest you to never dismiss any New idea before trying it, just because you never heard about it.

In our case, my Wife drives a 2000 Kia Sephia known as the "KiaStein", we live in the Warm Caribbean Honduras; and somehow everytime we use the A/C for prolongated times during Hot summer days, the Brake pedal became Spongy, and certain amount of braking power faded; and the only explanation I found, was that the Master Cylinder was Blown with Hot Air, that increased the Brake Fluid Temperature beyond the Normal average.

So, Long time ago, I obtained a Non-Flammable, Temperature insulating, FiberGlass Sheet of two feet long and one foot wide, and folded it, in order to let the hard side exposed on both sides; as you can see in the Following Photo:





Then I placed, wrapping the Master Cylinder as a Temperature Shield:




This is How the "KiaStein" works since some Months ago:



Problem = Solved.

Kind Regards.​
 
#43 · (Edited)
Disclaimer: use all the ideas I post, at your own Risk!

Yes, I tried with draining all the Brake Fluid from the System and pouring Fresh, synthetic High Temperature Brake Fluid in there, and the issue remained almost equal, so Changing the Brake Fluid was not the Solution in this Case, but insulating the Master Cylinder from too much heat, was the solution, by keeping the Master Cylinder, untouched by the Hot Air Flow from the two fans at the engine bay.

Maybe I will do something better than just a sheet of non-flammable fiberglass placed there, because despite that the material is non-flammable, it could turn into something inflammable, if it gets too oily.


_________________________________________________​

The second issue is related to the Proportioning Valves.

If you leave any car unused for long times, and you drive it as it "awakens", you'll notice that the brake pedal is working but it needs to be somehow "Charged" by a couple of Deep pedal pumps, prior to get where it should be / perform as it used to be, so it gets back all its normal "pre-charge".

So, since this Kia has proportioning valves intended for Drum Brakes, not for rear Disc brakes, it usually loose that "pre-charge" overnight, and the brake pedal needs to be "Pumped" deeply a couple of times during idle speeds, every early morning starts, otherwise its brakes will underperform a little.

But right after the pumping, the brakes stays working Flawlessly all day long, no matter how many errands you need to do; it only loose a little pre-charge during overnights, due to the design of the Proportioning valves.

We're so accustomed to do the Brake pedal Pumping on early mornings, prior to leave home, that we also are doing that to every other car we Drive, and somehow there are benefits from doing this.

Have you ever noticed that every car has a more sensitive brake Pedal, right after a Panic Braking?

The precharge gained by the early morning pumps, brings that sensitiveness to be there, all day long. :grin:
 
#44 · (Edited)
Aftermarket Vs. Original Parts

In another Subject, you must be aware that certain Brake Pads will bring better Braking Power and shorter distances to Stop, but that increased stopping power has a Price: Too much Wear on the Rotors.

Right after we purchased this Used Kia, we changed the two Front Rotors, and we used Factory brand New ones, but we used Aftermarket "Power Brakes" brand, brake pads. One year after that, the Pads were Gone, and the Rotors also were worn and damaged; but the car Had great Stopping Power...

Then we Purchased another set of two factory brand New Front Rotors, but this time also we purchased a set of factory brand new Brake Pads. We noticed a slightly Reduced stopping power. Eleven months after that, the Brake Pads were Gone (a little Earlier than the Aftermarket ones), but this time, the Rotors were absolutely Healthy, almost like New.


 
#45 ·
Avoid using Aftermarket Brake Pads!

Comparison between the Same factory original Brand, Front Brake Pads:



You can see that they're Smooth from the Top to the Bottom.

The Aftermarket ones, has lots of Random Metal Chunks that abrades Rotors.​
 
#46 ·
Original Vs. Aftermarket!

The following photo shows you the main Differences between the

Original Kia Rear Brake Pads, and the Aftermarket Rear Brake Pads:


 
#47 · (Edited)
Advice

In my own humble opinion, many aftermarket parts, especially Brake Pads, are Junk, because they do more Damage than Benefit; in fact to add certain amount of different sized & shaped metal chunks is somehow a Common Practice nowadays, among aftermarket brands of Brake Pads.

Several reasons are behind, among those you can find Production costs reduction, also that the Driver somehow "Feels" Better braking power with such Brake Pads, but the Damage done to the Rotors, moves a huge industry behind, to sell an increased number of Rotors yearly.

It doesn't worth to be changing Rotors frequently, in exchange to an slightly increase in Braking Power, that in fact, could be Dangerous in certain Circumstances; even a chunk of metal on a Brake Pad, can dig a trench in a rotor.

My Advice: Stay with Original Brake Pads, as long as you Can.
 
#48 ·
Brake Pads' Part Numbers

.



Not all the Second Gen Sephias uses the same part numbers,

Refer to your VIN to find the Proper ones for yours.​
 
#49 ·
Single Vs. Double Diaphragm Vacuum Boosters

Our "KiaStein" has more than a Year working with a Double Diaphragm Vacuum Booster for the Master Cylinder, the main difference between a Single Diaphragm and a Double Diaphragm boosters, is not found on their amount of Diaphragms, their Design or their increased boost capabilities, No.

The Main Difference will be always at the Brake Pedal:

A Single Diaphragm Booster provides a Smooth, Uniform Brake Pedal Travel.

Double Diaphragm Booster provides Softer feeling on the first ~ 3/5 of Travel, and becomes Harder to Push on the last ~ 2/5 of Travel, because that is the point where the First Diaphragm meets the Second one: Tandem Diaphragms arrangement.

An average Single Diaphragm Booster can produce up to 950 p.s.i. and work Well with four wheel drum systems or Disc front / Drum rear systems. These braking systems are Lighter than the four Disc brake system. These work best on older cars, because drum brakes were a Common feature, at least on the Rear axle of these cars.

Dual Diaphragm Boosters are needed for four wheel Disc brake systems, because they can produce a higher level of brake assist, far beyond 1000 p.s.i. even if their physical size is smaller. Also dual diaphragm brake boosters tend to give extra braking even when the vacuum from the intake manifold is Low.

More information: ~► Single Vs. Dual Diaphragm Brake Booster
 
#50 ·
However, Despite the added extra Boost from the Dual Diaphragm Boosters, I like most the uniform Feeling provided by a Single Diaphragm Booster.
 
#51 ·
First Year - 10,000 Miles Report

More than one Year / 10,000 Miles has already passed by, since I installed the rear Disc Brakes on the "KiaStein" also the four Rotors and all the Brake Pads were New.

I am satisfied Beyond all my Expectations; in fact, despite that those two minor issues related in previous posts of this thread, the Braking Performance of this Second Gen Sephia with Four Disc Brakes, the 15/16" Master Cylinder with Dual Diaphragm Booster, and newer style Proportioning valves, is really impressive; Better than the Average Car on same segment.

Nothing to do with the Original Lousy arrangement of Front Discs and the never self-regulated rear Drums Setup, that came with Leaky Proportioning valves, 7/8" master cylinder with single diaphragm Booster: it was pretty Unbalanced for the car for sure.
 
#52 ·
The Front Brake Pads were gone after this complete Year of Use, while the Rear Brake Pads still have the Half of their material; which is alright, because the main braking effort always rely on the Front Wheels while you're Driving to the Front, which is ~ 90% of the Time you Drive; and the Rears are now Really Working and helping the Fronts to do their Job as it Should.

 
#53 ·
Thanks!

Many thanks for being with me along all this investigation and modification process, I'm pleased to confirm that it is successful, and the car is now Safer and more reliable to drive, than it used to be.

Kind Regards.
 
#55 ·
I was wrong, sorry; my mistake...

After long time with the KiaStein running with the increased 15/16" bore master cylinder, my Wife told me that her car has a hard brake pedal that makes her tired from pumping it on traffic jams; so, I Decided to return to use a 7/8" bore master cylinder, but a Brand New one; in order to do different braking tests and feel if with the original size, the leg / foot effort for braking, reduces; but not the Braking force of the car.

And I must update here the Results, and also I admit that I was wrong.

I wish I should payed more attention back then, and followed good advice, such like this one:

Hi Jes,

Confirmed - don't change anything out, your current Master Cylinder should be within spec. for the rear calipers: you are not changing wheel size / the calipers are small, your current braking system should handle them without issue...
So, after removing the 15/16" master cylinder, placing in its place a brand new 7/8" master cylinder and swapping the piping that was modified, with another one from a donor car found on a local junk yard; everything (Except the Double Diaphragm brake Booster) went back to factory specs on the Master cylinder and pipings.
 
#56 ·
And the results of the different braking Tests I did, proves that the car, Really has a much better braking behaviour with the 7/8" bore master cylinder, rather than with the increased sized one.

Also the Brake pedal feels much, much softer and lighter to use; plus the braking power increases, as you get increased clamping force at the calipers with a longer running pedal, due to the Leverage effect.

But pedal doesn't travel too deep as it did with the old (stock) 7/8" master cylinder, which leads me to think that the stock one was worn and about to fail, back then...

anyhow; the "KiaStein" performs very good, braking with the 7/8" bore master cylinder, and the "in-tandem" double diaphragm brake booster.
 
#57 ·
So, please dismiss the idea of using an increased bore master cylinder, it works backwards; the bigger the Bore, the less pressure will have the brake fluid at the Calipers, because their chambers will be filled earlier and brake pedal gets tall and stiff; you will lose the advantage from the Leverage Effect, and thus means less braking Power.

The KiaStein performs great, with the original 7/8" size.

But the double Diaphragm brake Booster, is really Better than the single diaphragm one...

My wife is Happy now.
Kind Regards.
 
#58 ·
Besides brake pads, the only other thing that needed replacement so far, were the Parking Brake Cables; because the Honduran rebuilder used the old, rusty covers from the Junk Yard ones, and the steel cable never slide smoothly into those.

Despite that only one broke, I decided to change the Pair, you know: Left and Right, in order to have peace of mind, and long lasting parts there; otherwise the other old and rusty cable could fail soon.

The Left one has this Part Nº 0K2A2-44-420E

The Right one has this Part Nº 0K2A2-44-410F

Here's a couple of photos taken with my cheapo cellphone, of the old Cables next to the new ones, at the aftermarket Store's parking lot:




Now the Parking Brake Lever moves Smoothly, like never before. Besides that, everything has been Performing Flawlessly, so far, thanks to God. :thumbsup:

Kind Regards.
 
#59 ·
After more than 40K miles of hard and rude usage, including many daily short trips, and very long voyages across almost all the Central American countries, which is documented with Photos on my "KiaStein" Build thread whose web link is on my Signature Below; the rear Disc Brakes finally needed the brake Pads to be Changed for the first time.


This is how the Rear Brake Pads looked like, after all this time and Mileage:



That is Truly Amazing for this Sephia, when you compare such long lasting parts plus the Excellent braking Performance of the Rear Disc Brakes, to the Lousy rear Drum brakes' that it used to have, which needed rear shoe brakes every three months, and monthly adjustments.
 
#60 ·
About the FRONT Brakes.

The rear disc brakes continues performing awesomely, thanks to God; not having a single issue so far...

But the Rear disc brakes came off from a "Premium" second gen Kia Sephia (which is mechanically identical to the first gen Kia Spectra), which means that I have big 10.1" Discs in the Rear... and the smaller 9" Discs on the Front, which are the stock ones...

I read online that there were 10.1" front Discs for the Late (2001) second gen Kia Sephia (and the 2002 / 2004 Kia Spectra), known as the "Upgraded from Factory" front Brakes, available on Premium models...

So, my Natural desire was to obtain the Bigger 10.1" Upgraded front Disc brakes, to match the 10.1" rear Disc Brakes, to has the car on Balance, and remove the "unnatural" Small Front Discs / Big Rear Discs setup that I had on the "KiaStein" but, those upgraded front brakes are not easy to come by; I've searched for Years... (Literaly) ...and only came across of the standard 9" front discs; I wanted the "Upgraded" 10.1" Discs.

Until I found them, recently...
 
#61 ·
The last Real Kia, came from its factory on march, 2004 and was a Kia Spectra with the 1.8L engine; then from April 2004 and on, all the Kias including the Spectra, are really rebadged Hyundais, with only differences on body / interior design; so the Newer Kia Spectras are really Hyundai Elantras with the 2.0L engines; (in the same way that the Kia Sorento / Hyundai Santa Fe are Brothers, the same goes to the Hyundai Tucson / Kia Sportage, also the Hyundai Sonata / Kia Optima, etc...), so, to find a first gen Kia Spectra with the "Upgraded from Factory" front disc Brakes in 10.1" fashion, was not easy; as almost all the "Newer" Spectras I came across on Junk Yards, were from the Hyundai plattform, and those are completely different animals with the Sephia, parts doesn't interchange at all.

But thanks to God, I found one 2004 Kia Spectra, built in late 2003 with the 1.8L engine (Known as the "Old Body Style" somehow), which had the Famous Upgraded 10.1" front Disc Brakes.
 
#62 ·
Important information !!!

Also I must mention that to do this Retrofitting, I need:

► the Complete Hubs.
► the Rotors.
► the Calipers.
► the Disc Pads.
► along the Axles.

Because the "Upgraded from Factory" brakes, are completely different from the regular ones, the Axles on the upgraded ones are way much Beefier and also they are much thicker at the Hub's end, to the point that the axles from the Regular models doesn't touch the Splines inside the Hubs for the Upgraded brakes. However, the other end of the Axles (the tripod joint that fits at the transmission's cups) is Equal, even the shafts has the same measurements and Splines, as long as you use parts from a donor car that has the same transmission as yours.

This Means that I needed a donor car that has Automatic Transmission as the "KiaStein" is, otherwise the Axles will not fit...

Think about it, it was not easy to find the Perfect donor car here, in Honduras; but Miracles happens.
 
#63 ·
Finally, Photos (hoping that Photobucket allows me to share 'em Here)

This is the Donor Car, well... the front clip from an automatic 2004 model Kia Spectra premium, built in late 2003; which somehow came from the USA to the Local Junk Yard with only 31,000 Miles on the odometer:




The rim on the floor doesn't belong to it; the front clip already was empty, I mean without engine nor transmission; no interior parts, etc... and the front hubs were still with their 10.1" front Discs, Calipers, and Axles!




This is how I purchased them after I took 'em off from the Front Clip.​
 
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