PeteV

So, I think I warped my rotors on my '02 Runner, after upgrading to the Tundra rotors and calipers. I was headed down the mountain from Big Bear yesterday, and was getting quite a bit of pulsing out of the brakes when they heated up. I pulled my emergency brake to see if it was the rear drums, and the pulsing wasn't there.

I haven't been towing anything, or carrying an exceptionally large load (other than 3-4 people in the car, and some gear), so it seems strange to me that I could have warped these rotors.

I am thinking about getting them turned, but then I remove material, and it seems like they would warp again sooner.

What am I missing here? Have others had this problem? I thought this upgrade would make my brakes invincible, but apparently not.

MTL_4runner

Maybe a bit more detail would be good.....

What brand rotors did you put on? Were they new?
Were the calipers new? is one of the pistons sticking?
Did you torque your lug nuts properly?

I suspect you may have overtorqued the lugnuts because brakes can get extremely hot during continual use like coming down a mountain (much more so than just regular street use). So even Tundra rotors could warp in similar fashion due to uneven torque. I wouldn't bother turning the rotors, when they warp it's best to get new ones or just live with the vibration.

PeteV

Brand new Raybestos rotors and calipers, and detailed in the original thread. Lug nuts ALWAYS torqued properly.

Can you give me some info. on how I would check if one of the pistons is sticking? Since they are brand new calipers, I would hope not, but how would this possibly cause the rotors to warp?

MTL_4runner

Ok, that's good that you at least torqued the wheels so can eliminate that right away. To test for a sticking piston, you can use a large screwdriver in between the back of the brake pad and the piston and slowly pry the piston back into it's bore. You'll know just by feel if you have a sticking piston or not. A sticking piston holds the pad to the rotor and doesn't let the pad release pressure to cool the rotor......it can also add pressure to only one side of the rotor forcing the rotor off-center while it is very hot and causing it to warp.

Other things to check would be to make sure the rear drums were properly adjusted (drums are meant to take about 30% of the braking load so shifting too much to the front could cause excessive heat and possible warping). Also check that there isn't any debris that got behind the rotors when they were installed (rust, metal shavings, other debris).

PeteV

Okay, thanks. As far as the rear drums, I have heard conflicting reports, and had conflicting experiences with the adjustment requirements. I was told I needed to adjust the drums on my '98 Tacoma, and I checked them, and they were tight as could be after 80,000 miles.

It seems unimaginable to me that these vehicles would not have self-adjusting drums. Is this really the case? I've got 50,000 miles on the 4Runner, and have never adjusted the rear drums. If I need to do this, I guess I should. It just seems illogical to me that I would need to.

MTL_4runner

They are self-adjusting, but they should be checked as a possible cause.

It is entirely possible you got a "bad" rotor. You might take the truck down to the shop and have them take a runout reading to see if one or both rotors are in fact warped.

yamataco

Like MTL said, sticky caliper or a bad rotor is most likely. Unless you were driving really hard and simply overheated the brakes. I know I'm guilty of overdriving my brakes sometimes. I just finished my tundra brake swap on my taco, so I was hoping (like you said) that the bigger brakes would be bulletproof, but history has shown that I can break anything if I try hard enough...

profuse007

are your wheels balanced out?