4LO and Brakes

[roaniecowpony]

Have you done an ABS bleed?

The process of ABS bleeding involves regular system bleeding, then activating the ABS bleed mode with a JSCAN, Taser, or similar while bleeding.

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[dchemphill1]

This is weird. 32 degree down slope on Fins and Things and the brake held me just fine and I was in 4lo 1st gear manual mode. I agree with others you got an issue with your brake system.

 

[Medsker]

I agree with others you got an issue with your brake system.

I agree there is something wrong but the big question is what is the problem?

 

[roaniecowpony]

Have you done an ABS system bleed?

 

[Medsker]

I've done the abs bleed 5 times now and bled the brakes after I did it.

 

[Medsker]

Sorry, I feel like I'm stealing the thread. OP, let me know if you want me to start a new thread. I just figured it can help both of us.

 

[Left Field]

What about the Off Road+ buttton? I usually hit it when I drop t9 4LO but I’m now wondering if it is applying the brakes at times.
What exactly does that do?

If I'm understanding its description correctly, "Off Road +" has four major functions:
1) Changes transmission shift points
2) Changes throttle / gas pedal mapping (more aggressive 4H, less aggressive 4L)
3) Allows rear locker to be engaged in 4H
4) Reduced 'Traction Control' function

To me it sounds like a problem with the ABS, either something not functioning appropriately or possibly a leaking solenoid.

Have you tried a 'Full Off' of the ABS/Traction Control/Stability Control function?
(That is, at a complete stop, press and hold the TCS button for 5 seconds until you hear a chime and get a dash message).

LF

 

[AZ Hella]

What about the Off Road+ buttton? I usually hit it when I drop t9 4LO but I’m now wondering if it is applying the brakes at times.
What exactly does that do?

In 4LO the off-road+ button activates aggressive BLD action.

 

[Caymanedge]

Have you done an ABS system bleed?

No

 

[AZ Hella]

In 4LO the off-road+ button activates aggressive BLD action.

Once in Off Road+, the vehicle will begin to behave in different ways depending on the 4WD mode in use. The following enhancements will occur when using Off Road+.
4L (4WD Low)
• Engine/Transmission Calibration: Rock Crawl and controllability focus, change in shifting schedule when rock crawling, pedal calibration shifted to de-gain and low range, operates at lower vehicle speeds
• Traction Control: Aggressive brake lock differential tuning at slower speed or FIRST gear • Off Road+: Recall the last status between ignition cycles.

 

[Caymanedge]

Sorry, I feel like I'm stealing the thread. OP, let me know if you want me to start a new thread. I just figured it can help both of us.

Nope. Roll on

 

[Caymanedge]

Once in Off Road+, the vehicle will begin to behave in different ways depending on the 4WD mode in use. The following enhancements will occur when using Off Road+.
4L (4WD Low)
• Engine/Transmission Calibration: Rock Crawl and controllability focus, change in shifting schedule when rock crawling, pedal calibration shifted to de-gain and low range, operates at lower vehicle speeds
• Traction Control: Aggressive brake lock differential tuning at slower speed or FIRST gear • Off Road+: Recall the last status between ignition cycles.

I’m pretty sure when I activate the Offroad+ it tells me it disables the traction control. It definitely controls the brakes. I can hear the drivers front caliper/rotor working at a hard left turn. So that could be the overheating issue experienced in the past.
I guess an ABS bleed is in order to eliminate that potential issue.
I will also leave Offroad+ off unless necessary. I had the habit of just activating it when dropping to 4LO.
When running in 4LO I always manually shift, using the brakes minimally.
heading to Elephant Hill tomorrow…..

 

[AZ Hella]

I’m pretty sure when I activate the Offroad+ it tells me it disables the traction control. It definitely controls the brakes. I can hear the drivers front caliper/rotor working at a hard left turn. So that could be the overheating issue experienced in the past.
I guess an ABS bleed is in order to eliminate that potential issue.
I will also leave Offroad+ off unless necessary. I had the habit of just activating it when dropping to 4LO.
When running in 4LO I always manually shift, using the brakes minimally.
heading to Elephant Hill tomorrow…..

I use it all the time as well and have never noticed a problem.

 

[Willys41]

So I hate my brakes when off-roading in 4LO. Pedal goes all the way to the floor and on steep declines barely holding on.
I had some brake fade last year after a long day on the Rubicon but this is different, I have bled all the fluid and upgraded to a higher temp fluid.
It almost feels like the brakes are going on and off when in 4LO. I can hear the rotor grab screech at times.
Anyone experience this!

I had a similar problem and what it turned out to be is air in the ABS system.
A normal brake bleed WILL NOT remove the air trapped in the ABS.
You will need to do a ABS bleed to remove the air.
Here is a video that explains and why.
One note. Do not buy the autel scanner. There is a yearly subscription you have to buy for it to work.

 

[five9dak]

While it is normal to require high brake force in 4low, and torque converter automatics can sometimes overdrive their brakes depending on axle gearing and toque converter stall speed, your description of the pedal going to the floor is alarming.

I have had spongy brake issues that could not be solved until I got an ABS bleed at the dealership. I would recommend you do the same. My service writer only charged me half an hour of labor for this.

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