Brake problems... Help...

[markdejean]

Hello I am new to this forum. I have found a lot of useful information on this site. I just bought an 05 4Runner SE. I have a problem after installing a Daystar 2.5" leveling kit / front end alignment along with new brakes all around and brake fluid replacement.

I noticed when applying the brakes at low speed the brakes would pulse like when you have a warped brake rotor but it wasn't felt in the brake peddle(seemed to come from the back brakes). I thought it odd since every thing was new or almost new, I had the rear rotors turned. I thought I must have did something wrong but didn't know what. I have replaced brakes on all my cars and trucks for the last 35 years and never had a problem.

Yesterday I took the 4R out to do some playing around on dirt/ice and snowy roads(spring thaw). After using the DAC control and coming out onto the hard surface road when slowing to a stop the brakes would pulse like I had a warped rotor and as I got to a near stop it would shudder like the DAC is activated. Note that I am in two wheel drive at this point.The brakes go crazy when backing up and I apply the brakes. It acts as if the DAC is still activated in two wheel drive.

Does anyone have any advice as to what is going on????

 

[m85476585]

Yesterday I took the 4R out to do some playing around on dirt/ice and snowy roads(spring thaw). After using the DAC control and coming out onto the hard surface road when slowing to a stop the brakes would pulse like I had a warped rotor and as I got to a near stop it would shudder like the DAC is activated. Note that I am in two wheel drive at this point.The brakes go crazy when backing up and I apply the brakes. It acts as if the DAC is still activated in two wheel drive.

That sounds like ABS activating. Snow and ice are slippery, and it's trying to keep the wheels from locking up because that would cause you to lose control.

I've noticed that the brakes are over-active for a few seconds after turning off DAC, but if you had time to stop and shift to 2WD, it should be back to normal.

In 2WD mode if it's slippery while you are accelerating, TRAC will pulse the brakes to help send power to the wheel with more traction. On 2WD-only models it's called Auto LSD, but it works the same way on 4WD models in 2WD mode, as far as I know.

If you roll backwards in drive, HAC will pulse the brakes to try to stop you, but that shouldn't be active in reverse.

All these acronyms are just various algorithms on the ECU that controls the brakes. It's all the same physical system, and it has a few different ways that it can affect braking.

 

[majic]

I changed my front rotors, pads and calipers a few months ago and mine is doing the same thing. It drives me crazy. I dont know what causes it, hopefully someone can help.

 

[majic]

Nobody else has had this problem?

 

[przm]

I had a similar issue, but it doesn't sound exactly like what you're experiencing. it turned out to be one of the tires being unbalanced.

 

[jonesmw10]

I had a similar issue, but it doesn't sound exactly like what you're experiencing. it turned out to be one of the tires being unbalanced.

I'm having the same issue as you state and I'm thinking this is the problem too. I've hit quite a few large potholes this winter so I won't be surprised if I have a bent rim or unbalanced wheel. I do believe I have a brake caliper(s) hanging up too