Hey all! I recently purchased a 2012 Lexus IS250 AWD, and I absolutely love it (asides paying for premium gas haha).

The only concerns the car had was the alignment being off, which I have yet to fix, and the brakes. I know a four wheel alignment can be easily done at at shop quickly for like 80 bucks, although my concern is starting to grow on these brakes. By no means am I a mechanic, although I do my research and know the simplicities of cars and their maintenance. After researching and testing, I have came up with 3 ideas that may be the issue, and am hoping some people who are more familiar can help point me to the right direction.

The issue is that the brakes have a pulsating feeling and they kind of kick back in the pedal. Additionally, the car kind of stops then briefly "lets go", then stops and "lets go"... (repeat) when braking, resulting in a pulsing feeling. The pulsing does NOT occur in the steering wheel, but instead in the seats. From this, I automatically believe its something to do in the rear. This indicates something most likely with the pads or rotors. There will be occasional moments when I slowly brake and I hear some squealing, but it rarely occurs.

1) Warped Rear Rotors - Although I have been told its unlikely, I know that warped rotors are typically the primary cause for pulsing brakes. I have taken some looks at the rear and the front brakes and no significant signs of warping appear to my naked eye. I am not super familiar with what they look like, although I've gotten an idea from images online. I still believe it could be warped rotors though since the pulsing isn't that hard.

2) Uneven Pads and/or Deposits - From the looks of it, I think the brakes most likely have some uneven deposits, as I see lines of the deposits on the left rear brake. It just seems weird to me how such small deposits on brakes can make your entire car pulsate. I am unable to look at the pads since how compact it is, but they do look like they have life in them. Its possible that they are being unevenly worn but I can't get that great of a view.

3) Something with the alignment - The Lexus is pretty misaligned. The wheel is off center to the right. I know this isn't the craziest deal and its an easy fix but I am not too familiar with the complications it can bring in braking.

It may even be possible that its a result of all 3 of these. What do you guys think it is most likely? And where should I check first? I don't have too much time to visit a shop for my busy lifestyle, but I can probably work an appointment in if I know where to start. Additionally, since I kind of have to prioritize some of my budget, I was wondering whether I should fix the brake issue first or just get an alignment (neither really bother me, just whatever would be most important/critical.) Another question I had is if it where the brakes, should I do it myself or get the parts and then go to a shop for them to swap the rotors/pads for me?

Thanks for taking the time to read more on my story and I hope somebody out there can help me out!

 

There's no way to tell if the rotors are warped with your naked eyes.

I had warped rotors on my old Celica and I changed the rears, problem went away. Then the fronts started to pulsate on braking. Too many heat cycles.

Any brake pad deposits could be cleaned off with a few rounds of high-speed braking.

Alignment--IDK

Don't forget to check your rims for bends or cracks cos that can also cause pulsating but it would be constant, felt through the steering wheel and not just on braking.

 

Oh yeah the caliper pins can easily seize on IS. You can check yourself by removing the wheels and trying to remove the pins. Have some brake grease handy and see.

I had uneven wear on 3/4 of my inner brake pads and had to buy three new calipers. I went with A-Premium cos its cheapest and required no core charge. Just make sure to check the casting number on your calipers to match whatever you buy--either 28 or 32, I think should be stamped on there.

Good luck and keep updating us even after you fix your car. Others rely on this thread to troubleshoot.

 

As a mechanic, diagnosing brakes goes like this. If you feel the pulsing in the pedal, the rear rotors are warped, is you brake and the steering wheel shakes, the gront rotors are warped. So there is your issue, now you can take the rotors to be resurfaced or you can get new replacements. If your low on funds and cant get new pads at the same time and the old pads still have meat on them, you can get a sheet of like 80-120 grit sand paper and put it on a flat surface and sand them flat then reinstall. You will feel the difference on the first stop.

And yes, always check the slide pins on the calipers