Binding then "pop"

[zcruiser]

Sticking caliper piston? I had one on a Pontiac once. When cold, it would not release and the car would dive to the right.

I'd jack the 4runner up and see if you can freely turn both wheels to see if you can hear and/or feel anything. Front diff may be on its way out. Drain the fluid to see if there is a large amount of metal shavings in it.

Yup, done that too, nothing binding. I also had the rear wheels up on jacks while checking out the rear brake drums (nothing out of place or corroded there either), and decided to put it in gear while in 2WD with the jack stands. Behaved totally normal.

 

[99runnerwa]

a bit out there, but have you checked your universals and CV joints? they possibly could be worn enough to bind.

 

[Martinjmpr]

uhhh....

Interesting that nobody else caught the "2000 SR5 with a Center Diff Lock button to the left of the steering wheel?"

It's either (a) not a 2000 or (2) that's a rear diff lock, not a center diff lock.

Reason I bring this up is that if this is actually a 2001 model with the CDL, then this might be a TRAC/VSC issue? Just a thought.

 

[BrianSD_42]

Have you taken it to a mechanic for diagnosis - it might be time

 

[zcruiser]

Interesting that nobody else caught the "2000 SR5 with a Center Diff Lock button to the left of the steering wheel?"

It's either (a) not a 2000 or (2) that's a rear diff lock, not a center diff lock.

Reason I bring this up is that if this is actually a 2001 model with the CDL, then this might be a TRAC/VSC issue? Just a thought.

Not sure, but I think I corrected myself somewhere along the way that it's actually a rear diff lock. The truck was at the other end of the state at the time and I couldn't remember mainly because I've never used it.

Have you taken it to a mechanic for diagnosis - it might be time

So yeah, I finally admitted defeat and took it to a Toyota mechanic with lots of experience with 4x4's. He diagnosed that the rear brakes were incorrectly adjusted (hey I never touched the rears) and so he adjusted them to spec as well as the parking brake and... voila! No more grabbing. I misdiagnosed that it was the fronts grabbing because of the Tundra upgrade and assumed I did something wrong. I had opened the rear brake drums just to take a look and everything in there looked spotless.

But really, you would not believe how the brakes would grab hold of that truck and not let go until the engine torque overcame whatever was binding then it would pop loose. It felt like you were pulling something heavy with a chain then the chain broke it was that sudden.

Now just need to get a new ABS fuse and figure out how to get the old one out.