Doug P

Hello everyone, this is my first post. I have a 99 4runner that I bought about a month ago. It had brand-new brake pads when I bought it but I noticed some vibration (that wasn't too bad), however when coming back from the mountains downhill it was REALLY bad. I decided to replace the rotors a couple of days ago but the vibration is still there. I was driving today and I thought "maybe it's the rear brakes" so I put on the e-brake while driving to engage the rear brakes and sure enough I feel the vibration so I'm like "oh, I guess the rear brakes are the issue". I decided to have the drums turned and the vibration is still there BUT I tried putting on the e-brake again and the vibration is gone...so it seems like turning the drums did what it was supposed to do but, like I said, when I brake the vibration is still there. I tried downshifting to see if I got the same vibration and I didn't...it only seems to happen when I brake but I don't really see what the problem could be since the front/rear brakes are 1 month old and the rotors are 2 days old and the drums were turned today...any idea of what the problem is...or any tests I can do that you can think of?

Malcolm99

It is common for the 3rd gen to experience warped rotors and not advised to turn them. I assume you replaced the newer pads with brand new pads with the new rotors, and always compare brake parts to old components. A sticky calliper piston can cause warping aswell. you might have to do the front over again with different quality rotors and pads making sure all the mating surfaces are clean and free of debris. Your drums originally came balanced with weights on them and quite often they rust and fall off usually unnoticeable though.

Doug P

The pads were only a month old so I didn't replace them when I replaced the rotors. You think 1 month would be enough to mess up the brake pads?

Malcolm99

Yes those pads broke in to the old warped rotor, unless you had a way to sand them down perfectly flat they cannot break in and seat perfectly on the new rotor., technically they will eventually break in but it is not good practice to reuse brake pads even when "newish" as they will apply pressure unevenly and may cause premature warping and poor braking.

Doug P

Thanks...yeah you were right. I pulled the pads out and on the driver's front the pads had worn down 1mm more on the top than on the bottom. I called a couple different places that both said that amount of wear would not cause a problem but my intuition told me they were wrong so I went and bought some brand-new ceramic pads and popped them in and the vibration went away. Thanks again!

Malcolm99

Glad to help, brakes can be tricky sometimes and a very sensitive on these trucks.

psstrymecki

I saw your thread and it instantly reminded me of the same issue I had with my T4R. I had completely replaced my rear brakes and axle seals, only to have that vibration only a few hundred miles later, due to my right rear shoes adjusting themselves tight. I had checked the hardware and made sure everything was correct, and adjusted all the park brake cables, that got me another 1200 miles and a severely warped drum. I replaced the drum and cleaned everything, same issue 1200 miles later. I finally broke down and bought factory shoes 4000 miles ago and no issues since