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

jgorm · 12-03-2009, 09:22 AM

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.

**mdm** · 12-03-2009, 09:31 AM

Low fluid?
Air in the lines?

**Unlimited04** · 12-03-2009, 09:38 AM

Quote:

Originally Posted by jgorm

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.

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.

jgorm · 12-03-2009, 10:00 AM

Quote:

Originally Posted by mdm

Low fluid?
Air in the lines?

Fluid level is fine, but maybe there is air in the lines.

Quote:

Originally Posted by Unlimited04

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.

**mrblaine** · 12-03-2009, 10:02 AM

**TheBoogieman** · 12-03-2009, 10:03 AM

Pads are wore out?

jgorm · 12-03-2009, 10:07 AM

Quote:

Originally Posted by mrblaine

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.

Quote:

Originally Posted by TheBoogieman

Pads are wore out?

No, but how would that cause a decrease in performance unless they were totally worn down to metal.

**Unlimited04** · 12-03-2009, 10:16 AM

Quote:

Originally Posted by jgorm

Fluid level is fine, but maybe there is air in the lines.

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.

DOT4 is absorbs moisture more slowly with a higher initial boiling point. However DOT4 suffers a larger drop in boiling point as it accumates moisture than DOT3.

Source: Why Change Brake Fluid

I used DOT3 because I was cheap and its dry out here

jgorm · 12-03-2009, 10:29 AM

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!

jondotcom · 12-03-2009, 10:30 AM

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.

**TheBoogieman** · 12-03-2009, 10:31 AM

Quote:

Originally Posted by jgorm

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.

No, but how would that cause a decrease in performance unless they were totally worn down to metal.

When mine are worn down to the point of replacing them,the pedal goes way down because the fluid level is down.I have the opposite problem.My 03 with 35's stops better than my 98' did with 31's.Go figure.

**mdm** · 12-03-2009, 10:32 AM

Glazed pads and/or rotors
Grease or oil on the rotors

jgorm · 12-03-2009, 10:36 AM

Quote:

Originally Posted by TheBoogieman

When mine are worn down to the point of replacing them,the pedal goes way down because the fluid level is down.I have the opposite problem.My 03 with 35's stops better than my 98' did with 31's.Go figure.

wouldn't the fluid only go down in the reservoir? How you that effect pedal position?

**mrblaine** · 12-03-2009, 10:38 AM

Quote:

Originally Posted by jgorm

Fluid level is fine, but maybe there is air in the lines.

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.

Alright, here's why I was laughing. First off, there is no such word as hydroscopic when it comes to water absorption and brake fluid.

Dot 4 is not overkill when you consider that the master cylinder resides in one of the areas of the highest heat accumulation under the hood of a TJ and is very susceptible to vapor lock.

The higher initial dry boiling point and the fact that we can and quite often do drive to much higher elevations where boiling points are reduced makes it a worthwhile investment.

I also well understand that some rigs do have decent brakes, some don't and now you understand it as well. It's purely a function of the rig and there is no across the board answer as to why some do and some don't.

As far as the differences, the combo valve is slightly different and I'm guessing it is to bring in more rear bias due to the longer wheelbase.

The brake lines are black and more corrosion resistant and at some point they switched from a double flare to a metric bubble flare at least at the combo valve, but not at the master. The master is still the same as is the booster.

I worked on an Unlimited with bad brakes and swapped out the combo valve, master, booster, and all the pads, calipers, discs and hardware and never got it much better than it was and only after swapping on one of Van's kits could we get it to lock up 35's.

One item of note was that it responded much better to swapping in EBC green pads in the rear than any rig I've messed with.

**mrblaine** · 12-03-2009, 10:41 AM

Quote:

Originally Posted by jgorm

wouldn't the fluid only go down in the reservoir? How you that effect pedal position?

It doesn't with rear discs, only drums. As the shoes wear with drums, the friction surface is farther away from the drum and the take up springs retract them back to the anchor point. As you apply the pedal, you don't start building resistance in the pedal and system pressure until they contact.