Brake Fade - Soft Pedal

[Caymanedge]

Spent a couple long days on tough trail with a group. All three JL based rigs had brake fade and required pumping the brakes often to get a solid pedal.

I’m wondering if 4LO and manual shifting somehow engages the brakes to control the speed. Spent hours in M1 and M2. I never used hills decent. Can’t imagine my use of the brakes created that much heat unless one or. Ore were dragging the whole time.

Any input besides flushing and upgrading fluid or upgrading calipers?

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[Reinen]

It shouldn't use the brakes in 4LO M1/M2, however when you do use the brakes that gear ratio gives the idling engine a lot of leverage.

What % of the time would you say you had the brakes applied? Even slightly counts. Every moment the brakes are applied heats them up. Every moment you're 100% off the brakes and entirely controlling speed with the drivetrain cools them down.

 

[Caymanedge]

At times a lot, like on/off for 15 of 20 minutes. I just can’t envision crawling adding that kind of heat to boil the fluid but maybe that’s it.

 

[Reinen]

At times a lot, like on/off for 15 of 20 minutes. I just can’t envision crawling adding that kind of heat to boil the fluid but maybe that’s it.

If you're crawling slower than M1 sometimes it's better to pop into neutral. That way the brakes are only fighting gravity instead of gravity + engine idle. But return to engine braking as soon as 4LO M1 slows you down again.

 

[VKSheridan]

The master cylinder on the JL doesn’t carry much displacement so it’s not uncommon to desire a “double pump” under normal conditions to stiffen the pedal (Absent air in the brake system of course).

This would appear to be by design to reduce the risk of uncontrolled sliding of your wheels off a surface versus controlled wheel rotation with resistance.

If it “feels” like it is worsening as the trail goes on, take a hard look at your rubber brake lines connecting to your calipers. Jeep likes to use extremely soft material and the damn things expand like a blowfish instead of staying rigid and leaving the movement at the caliper.

If you lifted your ride and are relying on the factory brake lines, you might notice the angles being tight when flexing. This too will weaken the brake lines.

A good countermeasure for either cause is a GRIMM BRAKE LINE KIT (JL). It keeps your brakes soft enough to crawl but responsive enough to stop without multiple pumps.

 

[Old Jeeper]

Spent a couple long days on tough trail with a group. All three JL based rigs had brake fade and required pumping the brakes often to get a solid pedal.

I’m wondering if 4LO and manual shifting somehow engages the brakes to control the speed. Spent hours in M1 and M2. I never used hills decent. Can’t imagine my use of the brakes created that much heat unless one or. Ore were dragging the whole time.

Any input besides flushing and upgrading fluid or upgrading calipers?

Its not calipers you need, its better pads. I run the EBC pads and have for years. A friend of mine owns an Engineering Company and they do Automotive testing, anything, and everything. So he tested brake pads for Chrysler and EBC came out the winner over everything else. Chrysler was putting them on the REALLY GO FAST cars that run the Elephant motors and the old VIPERS.. EBC makes them specific fo jeep, they will stop you on a dime for sure.

https://ebcbrakes.com/products/ebc-extra-duty-light-truck-jeep-and-suv-brake-pads/

You can do a front-only brake job in about 30 min per wheel, about 80% of your braking ability is on the front.

 

[av8or]

I have never had the soft brake pedal in my wrangler, but a few weeks ago my friend in his diesel gladiator complained about this several times while we were on the rubicon. We kept checking the reservoir and checking for leaks, but everything was fine. He said the pedal would go to the floor unless he pumped it. Interesting.

 

[Caymanedge]

I

If you're crawling slower than M1 sometimes it's better to pop into neutral. That way the brakes are only fighting gravity instead of gravity + engine idle. But return to engine braking as soon as 4LO M1 slows you down again.

was doing that the second day where I could, but it was so up and down it wasn’t a lot.

The master cylinder on the JL doesn’t carry much displacement so it’s not uncommon to desire a “double pump” under normal conditions to stiffen the pedal (Absent air in the brake system of course).

This would appear to be by design to reduce the risk of uncontrolled sliding of your wheels off a surface versus controlled wheel rotation with resistance.

If it “feels” like it is worsening as the trail goes on, take a hard look at your rubber brake lines connecting to your calipers. Jeep likes to use extremely soft material and the damn things expand like a blowfish instead of staying rigid and leaving the movement at the caliper.

If you lifted your ride and are relying on the factory brake lines, you might notice the angles being tight when flexing. This too will weaken the brake lines.

A good countermeasure for either cause is a GRIMM BRAKE LINE KIT (JL). It keeps your brakes soft enough to crawl but responsive enough to stop without multiple pumps.

thanks for the insight. I run a light truck pad, Hawk I think. I hadn’t considered the rubber brake lines. I’ve checked the clearance on them but upgrading while flushing fluid is a good idea. Some guys I rode with changed to a Chevy 1500 size 15 master cylinder or something like that. Have to research that more.

 

[Caymanedge]

I have never had the soft brake pedal in my wrangler, but a few weeks ago my friend in his diesel gladiator complained about this several times while we were on the rubicon. We kept checking the reservoir and checking for leaks, but everything was fine. He said the pedal would go to the floor unless he pumped it. Interesting.

^^This^^
We were on the Rubicon and that’s exactly what we experienced. No doubt the 6-8 hours a day of crawling never gave them a brake . We debated bleeding them but decide the problem would probably be back soon so we pumped on.

 

[av8or]

^^This^^
We were on the Rubicon and that’s exactly what we experienced. No doubt the 6-8 hours a day of crawling never gave them a brake . We debated bleeding them but decide the problem would probably be back soon so we pumped on.

What’s interesting is that it should be me that has the issue as I’m a two pedal driver when off-road. I drag the brakes a lot on trails like the rubicon.

 

[Willys41]

I had the same problem and I fixed it
THE WRANGLER MUSHY BRAKE SYNDROME FINLEY FIXED


https://www.jlwranglerforums.com/fo...ake-syndrome-finley-fixed.82912/#post-1734148

 

[Lionel Hutz]

Spent a couple long days on tough trail with a group. All three JL based rigs had brake fade and required pumping the brakes often to get a solid pedal.

I’m wondering if 4LO and manual shifting somehow engages the brakes to control the speed. Spent hours in M1 and M2. I never used hills decent. Can’t imagine my use of the brakes created that much heat unless one or. Ore were dragging the whole time.

Any input besides flushing and upgrading fluid or upgrading calipers?

I recently did Ophir and Imogene Pass and used 4Lo/manual shifting extensively on the descents. I didn’t notice any usage of the brakes during those times. My speed was controlled entirely by the gear I was using. I could go significant distances without ever touching the brakes. I only used the brakes when I need to pull over to let someone by. Even then, I could shift to 1 and be almost at a complete stop.

I did notice that when I used the brakes they needed to work a little harder to keep the Jeep stopped. I assumed this was from the 4Lo final ratio and just needing more stopping/hold power to overcome it.

I only noticed brake usage when I engaged hill descent. I tried it once at the ORV park and never used it again for that reason.

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