ZaxF

iTrader: (3)

I need some assistance diagnosing an issue. As stated im leaking brake fluid from somewhere. Two days in a row when it was very cold my reservoir was below the min line. After this happened I pulled all the pads and cleaned the calipers so I could try and locate the leak and nada, zip, zilch. I rechecked all the bleeder valves for leaks and nothing there. Put everything back together and no leaks or loss of fluid for 9 days and now this morning, low fluid again. I can k my assume that its coming from a caliper and burning off ever so slowly. What would you guys suggest to diagnose where it's coming from or should I just rebuild the calipers.

tas02

iTrader: (2)

Any evidence of leakage around the master cyl. pushrod?

ZaxF

iTrader: (3)

Below the reservoir? If so, that's bone dry.

MisterSkiz

iTrader: (2)

Pull the check valve out of the brake booster and see if you can see or feel any fluid inside of the brake booster...don't drop anything in there!

tas02

iTrader: (2)

Under the dash, where the pushrod goes into the mc.

ZaxF

iTrader: (3)

Turns out the master cylinder was leaking into the booster. Need to replace everything. Ugh.

newgsman

iTrader: (4)

Hope this a warranty repair?

ZaxF

iTrader: (3)

It sure isn't. Not cheap either.

msgs350

iTrader: (2)

Just curious. Is this not a warranty item or are you out of warranty (years/mileage)?

MisterSkiz

iTrader: (2)

That's very strange that it would happen.

Do you go to your dealership often? Ask them if they would cover it under a goodwill repair...might be they cover parts and you pay labor.

ZaxF

iTrader: (3)

'12 with 77k. My friend is the service manager and he is cutting me a deal less than $2k

MileHIFcar

^^^^Damn that can't be normal for a 2012 with 77k?? Why do you think it went out so soon? Is it because you track your car a lot?

ZaxF

iTrader: (3)

All he could tell was the seal went bad. No apparent correlation to track usage or using RBF. Apparently it is a minor issue in some other models. Maybe I just got unlucky.

newgsman

iTrader: (4)

It would be interesting to know if the master cylinder is the same as the other IS* cars or any other Lexus model. If so we can poll others to see if anyone else has experienced this failure.

We already know that the vacuum check valve in the brake booster is pretty common among Toyota/Lexus cars.