Our 02 es300 suddenly has a bad brake issue. I’m a little stumped; think I got it but not sure.

- Brake light on, ABS light on.
- Bad chatter and vibration on braking, feels like Left front
- ABS is indeed inop, I can lock up the brakes easily.
- Fluid was very dark, almost a black tint - was fresh and clean not long ago.
- Fluid not low, no obvious leaking.

It was working fine recently; it happened suddenly. Pads and rotors in good shape. Fluid has been changed regularly for a LONG time. Most recent fluid inspection/change was January this year per my notes. The car has been sitting mostly for nine months with only occasional short drives; awaiting my step-daughter to get her license (she did yesterday). I test drove the car just to triple check things and found this issue.

I’m a little confused how the fluid darkened so rapidly. The problem seems to be the left front/right rear diagonal circuit only per my butt dyno. If contamination/leak, I’m not sure why fluid level would not be low. Could it be a stuck piston/failed seal in the LF caliper? Letting contamination in, stuck, and disabling ABS? It’s a 2002 and higher mileage, and I cannot recall ever detail stripping and rebuilding the calipers; I think they are all still original.

My instinct is to get rebuild kits, and pull and rebuild the front calipers, re-evaluate.

Should be stored code(s) find out what they are. I've never seen brake fluid darken quickly, when you say fluid changed on the regular how often exactly?

I drained/ filled the reservoir annually, always clean fluid in it, and it was clean as recently as January. Calipers gravity bled less often but every few years. I had documented checking it this past Jan per my spreadsheet/notes, so it would have been a-ok then or I would have noted it.

I’ve never seen fluid go dark so fast either; that baffles me. I didn’t have my Toyota reader w/me (the car is at my step-son’s place now) and I’ll ask him to read OBD codes today. We had a family event going on yesterday so I didn’t have time to dig into it.

I own 7 cars (I think, can't remember lol) none of them have ever done this. Puzzling. But logically this is rubber breaking down and becoming part of the liquid I don't see what else makes sense. If the front LH caliper is seizing then it will trip up the ABS computer, wheel could partially lock causing ABS to kick in but then it can't modulate the piston properly. Hopefully there isn't something more serious going on like an ABS module going out.

I mostly don't rebuild calipers anymore too messy especially the cleaning phase. If PowerStop or Centric is an option I'd buy that. PowerStop does a great job of caliper rebuilds and their red versions have a quality paint job.

edit - also PowerStop uses original cores
https://www.rockauto.com/en/moreinfo...t=1704&jsn=456

Hello,

Did you notice any of the Vibration with the Wheels Locked? If so, it can indicate that the Vibration is caused by the ABS Module itself, even though it doesn't function. I've had cases of Brake Rotor developing some vibration after the car was sitting for a long time, but those usually resolved themselves by simply removing the Brake Rotor and cleaning all the surfaces. There aren't too many things that can cause the Vibration to occur, so I would suggest to start by at least pulling the offending wheel and checking if the Rotor is Warped, and if the Boots on the Caliper are damaged.

The concerning part is that the Brake Fluid went dark right as the ABS failed to function, it can indicate that either one of the seals deteriorated into a puddle, or some debris did manage to find its way into the system, regardless, it can be an indicator that the ABS Module as a whole has failed and may need a rebuild/replacement. So far, you best bet would be to at least pull the Codes that trigger the ABS Light in the first place and go from there.

Hope this helps and best of luck!

That’s all I can think of, too. I ordered two caliper rebuild kits and later this week I’ll pull both calipers, clean and rebuild them. It also gives me an excuse to get the wheels off the car, refinish them, and the calipers. Flush fluid and cross fingers it’s not the ABS module.

The car has moved only 550 miles since 1/25/25 (per my notes), and been sitting outside in very rainy Snoualmie, WA. May or may not have something to do with it.

Yep that’s my fear - could be ABS module. The wheel (LF as it felt to me) chattered under any braking, when ABS should be there or not.

My step-son just checked but there are not brake codes with OBDII. If there are codes, it will take my Toyota device to read them, but I didn’t have it with me yesterday (I’m an hour away). I’ll go up and get the car Tues. I think and then start tearing into it. I’ll just go ahead and pull both calipers, clean and re-assemble them, new seals, check rotors, etc. $20 to do that and it is worth doing anyway. I usually do it on a vehicle sometime after 150k miles. I don’t think I’ve ever had these calipers off and it has 340k on it, all but the first 90k of that in rainy western WA.