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The brakes on my 06 unlimited suck way worse than my old 02 TJ brakes

3K views 27 replies 8 participants last post by  mrblaine 
#1 ·
Not sure why yet, but i hit the floor when checking them, and that's never good! The pedal feels much softer too. My old TJ stopped way better on 33s than my 06 does on 31s. It never even came close to hitting the floor during tons of brake tests. Granted the unlimited weighs a little more, but not that much more! Is there any difference in the brakes systems between the 02 and 06? I'm going to do a full overhaul, fluid, pads, and rotors.
 
#4 ·
Fluid level is fine, but maybe there is air in the lines.
the LJs all have rear discs, whereas your 02 probably had rear drums. thats about the only difference.

The brakes on the LJ's just suck bad, even with EBC/Centric's, my brakes leave a lot to be desired on 31s. My mom's 06 LJ is the same way, but it does brake slightly better than mine (30s, no armor, bone stock).

You can change out the fluid to DOT4 to try to get all the moisture out of the current fluid, but honestly I think the LJ's should have had 2-piston calipers in front from the factory.
I did the disk swap on my 02 so that is the same. I think dot 4 is way overkill on a jeep. I don't see any way that fluid temps would get high enough to use dot 4. From what i remember dot 4 is more hydroscopic than dot 3 and needs to be changed more. I do run dot 4 in my mustang.
 
#19 ·
Stuff it moron. Ye know not of what ye speak and if your chemistry degree is defined by your knowledge of the words used to describe water absorption, then you're a very poor one.
I'll admit there is some ambiguity about hydro vs hygro scopic, but its a real word in the industry. Ask a real scientist and they will understand. And there you go with the name calling again. I swear you call more people idiots and morons than everybody else put together. Its even funnier when you are the one who is wrong.
WikiAnswers - Name a hydroscopic salt
Non-hydroscopic sweetener composition and method for preparation of same - US Patent 6461659 Description
Mean diameters of hydroscopic particles as functions of relative humidity and in
Hydroscopic polymer gel films for easier cleaning - Patent 6926745
Sometimes your arrogance is mind boggling.

Actually I do say it because I've had it, experienced it and fixed it with higher boiling point brake fluids from when I wheeled in Big Bear.

Sitting idling in line, drop down off a ledge, pedal goes to the floor with no brakes, get moving, more airflow, brakes come back perfectly. Draw your own conclusions.
So some minor air flow cooled the brake fluid down in less than a minute? Maybe it was the extreme angle that allowed air into the pickup. Or it was some old "wet" fluid and changing to dot4 had nothing to do with the results you saw.
 
#20 ·
I'll admit there is some ambiguity about hydro vs hygro scopic, but its a real word in the industry. Ask a real scientist and they will understand. And there you go with the name calling again. I swear you call more people idiots and morons than everybody else put together. Its even funnier when you are the one who is wrong.
WikiAnswers - Name a hydroscopic salt
Non-hydroscopic sweetener composition and method for preparation of same - US Patent 6461659 Description
Mean diameters of hydroscopic particles as functions of relative humidity and in
Hydroscopic polymer gel films for easier cleaning - Patent 6926745
Sometimes your arrogance is mind boggling.

So some minor air flow cooled the brake fluid down in less than a minute? Maybe it was the extreme angle that allowed air into the pickup. Or it was some old "wet" fluid and changing to dot4 had nothing to do with the results you saw.
You quoted Wiki? I gave you the correct info, info I first discovered looking for a definition and then later verified with calls to real chemists.

When it comes to water absorption by brake fluid, the correct term is hygroscopic as even your first link proved. Nice try though. As a chemist I would think you'd err on the side of correctness, but I guess I was wrong. And a hydroscope is still a device for looking underwater whether you want it to be or not.

Being right has nothing to do with arrogance. It's only perceived that way by those that are wrong.
 
#3 ·
the LJs all have rear discs, whereas your 02 probably had rear drums. thats about the only difference.

The brakes on the LJ's just suck bad, even with EBC/Centric's, my brakes leave a lot to be desired on 31s. My mom's 06 LJ is the same way, but it does brake slightly better than mine (30s, no armor, bone stock).

You can change out the fluid to DOT4 to try to get all the moisture out of the current fluid, but honestly I think the LJ's should have had 2-piston calipers in front from the factory.
 
#7 ·
laugh all you want! This goes to show you that not all TJ brake systems are created equal and when you are freaking out on how someone can run 35s without your $$ vanco system, this is why.
Pads are wore out?
No, but how would that cause a decrease in performance unless they were totally worn down to metal.
 
#9 ·
thanks! I knew dot4 had to be changed more. There is no reason to ever want to run dot 4 in a jeep. Why would you ever get the brake fluid that hot? Reminds me of that guy that posted that he needed new brakes to drive down steep hills in neutral!
 
#10 ·
My brakes also felt weak on my LJ, so I bled them out completely with dot4 and put the cheapest semi-metallic pads I could find on (from what I understand the semi-mettallic make more dust but have more bite than organic and ceramic).

The brakes are much better and I actually discovered in a panic situation I can lock up my 32s on the freeway! The only thing I still notice is that they still take much more pedal pressure to have the same result as my other vehicles, meaning they stop fine, but you have to mash the pedal harder.
 
#21 ·
Again, from your own link-

Cut and paste- Please note the bolded section Mr Chemist. Just because it's common to erroneously use a word, does not make that word correct.

Hygroscopy is the ability of a substance to attract water molecules from the surrounding environment through either absorption or adsorption.

Hygroscopic substances include sugar, honey, glycerol, ethanol, methanol, sulfuric acid, methamphetamine, iodine, many chloride and hydroxide salts, and a variety of other substances.

Zinc chloride and calcium chloride, as well as potassium hydroxide and sodium hydroxide (and many different salts) are so hygroscopic that they readily dissolve in the water they absorb: this property is called deliquescence (see below). Sulfuric acid is not only hygroscopic in high concentrated form, its solutions are hygroscopic down to concentrations of 10 Vol-% or below.

Because of their affinity for atmospheric moisture, hygroscopic materials may need to be stored in sealed containers. When added to foods or other materials for the express purpose of maintaining moisture content, such substances are known as humectants.

Materials and compounds exhibit different hygroscopic properties, and this difference can lead to detrimental effects, such as stress concentration in composite materials. The amount a particular material or compound is affected by ambient moisture may be considered its coefficient of hygroscopic expansion (CHE) (also referred to as CME, coefficient of moisture expansion) or coefficient of hygroscopic contraction (CHC)-the difference between the two terms being a difference in sign convention and a difference in point of view as to whether the difference in moisture leads to contraction or expansion.

A common example where difference in this hygroscopic property can be seen is in a paperback book cover. Often, in a relatively moist environment, the book cover will curl away from the rest of the book. The unlaminated side of the cover absorbs more moisture than the laminated side and increases in area, causing a stress that curls the cover toward the laminated side. This is similar to the function of a bi-metallic strip. Inexpensive gauge-type hygrometers frequently seen domestically make use of this principle.

The similar-sounding but unrelated word hydroscopic is sometimes used in error for hygroscopic. A hydroscope is an optical device used for making observations deep under water.
 
#27 ·
LOL at you having to look up a word i used, then do research to try and explain that its not a real word, even though its well understood in the industry. thanks for the entertainment! keep trying blaine.
 
#28 ·
Don't flatter yourself. I looked up the word you used incorrectly long before you even owned a Jeep. I did that many years ago when I was researching the properties of brake fluid, the differences between wet and dry boiling point and what the commonly accepted moisture levels were before the wet boiling point was reached.

The only industry the incorrect use of a word would be in is one rife with morons.

Again, regardless of how many times you use it incorrectly, you still can't make it right.

What I was actually trying to clarify was the difference between miscible and hygroscopic.
 
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