The disappearing brake fluid....help.

skip to the end if you just want to see the question..

Soo.. its been frustrating past couple of days its been for me and my tacoma... to start my brake fluid was mysteriously disappearing...literally. i looks around my front brakes followed the lines nada... pulled apart my drums... nada.... it looked like it may have been my passenger side drum... but it could have been left over residue from the diff fluid when the seal went out. the brake cylinder was bone dry..so i said eff it warranted the cylinder anyways and replaced the brake line that went to that drum cause it had a kink in it. drove around for a little bit and its the brake fluid still disappearing no signs anywhere..

got home looked around the peddle again, around the master cylinder, all the brakes, popped off the wheels again...dropped the drums again.. nada... now im like what the fuck... so i refill the brake reservoir closed the hood and said fuck it its late ill mess with it tomorrow..

today..Drove the truck around again just for a little bit to go to home depot. and back again and brake light came on again as expected. by this time im thinking enough brake fluid should have filled what ever the fuck its disappearing to cause almost half a pint of brake fluid has Houdini'ed from the reservoir by now....

and..the fucking hood wont open...dismantled the latch under the dash so i can pull it manually. nothing.. reached under the the hood yanked the shit out of the cable. nothing..now im just like what the fuck.. just said fuck it took off the 3 screws holding in the latch and ripped the latch out with the hood.

at this point i still have no clue where my brake fluid is disappearing too... so i guess im just gonna replace my master brake cylinder..and hood latch.. and hood latch cable...


Now the question.

Lets just say it was the master brake cylinder and it was leaking into the brake booster. Is that even possible? at this point its the only thing i can think of since i cant find any brake fluid anywhere. You would think it would leak out before it would leak into the booster...

 

Standard or automatic? If standard, could the clutch cylinder be the culprit?

 

I have never personally had this happen, but understand it can leak into the booster.

 

I'd seen some truly weird leak on older t4r/truck before. Somehow the seal where the piston shaft from the cylinder is weaken and fluid will drip into booster and come down on the inside of your firewall and cushion carpet. If you just look at the carpet from staring at it, it don't look wet until you pry the carpet and cushion off.

Worth a shot..

 

Brakes and the clutch don't share hydraulics.

 

its an auto 02. I wish i had a manual this is the first auto vehicle i've ever owned in 18years of driving lol. i can say auto is easy, but the throttle response of auto really sucks when you been driving manual all your life.

anyways. so hitched a ride to the local autozone and just bought a duracrap master cylinder just encase before they closed and it got to dark to work on the truck. it gave me some time to relax after having to deal with the stupid hood thing... It turns out that it was leaking into the booster some how. when you look at the design you would think it couldn't, but it some how did.

at this point i just stopped caring how and why. all i can say is the brake booster was surprisingly easy to get out compared to other cars that i've worked on. I had to remove it to drain the fluid and clean it. i see no residue inside the vacuum line, but having brake fluid mixing into your motor oil is not a good thing. I rather spend the 30bux to change the oil than risk the off chance of contamination and destroy my motor seals. its unlikely enough would make it in to cause a problem, but than again i've never seen brake fluid leak into a brake booster before either...

now to find a new hood latch since i destroyed mine ripping it out with the hood. bend some metal back into shape..and hope my toyota goes back to being a toyota.

 

Check the brake load pressure valve it's the thing that has the rod going to the rear end. Had to replace mine. ..

 

Some do. They use the same reservoir.
http://www.jeeppatriot.com/forum/5-...h-problem-related-brakes-help.html#post435715

 

We're not talking about jeeps.

 

https://www.tacomaworld.com/threads/clutch-fluid-reservoir.37159/#post-600077

How about TACOMAS!

 

WE'RE TALKING ABOUT 1ST GEN TACOMAS.

And you're giving inaccurate information. Someone down the road may find this thread with the same symptoms and spend half a day diddling with their clutch hydraulics for a brake issue, because you've giving BAD information.

 

Look, I was throwing out possibilities, never having a standard Taco myself. My sons Mitsu Eclipse had that along with many other cars. If you want to play Horses Derriere, please continue. I'm done.

 

So, just curious I've been getting a P0171 on my '03 Tacoma 4x4 3.4L manual. I believe it is the brake booster; when I either apply pressure to the brake or let off the brake it produces a high pitch whistle. I cleaned the MAF and O2 sensors, looked everywhere else for value leaks, but this is where I'm at now. How challenging are we talking and do I really need to replace the master cylinder while I'm at it? Do I have to disconnect all the brake lines if I keep my current master cylinder? Replacing all the brake fluid is a given, but any other suggestions or tricks that might make this easier? Oh and not really wanting to destroy the hinge to my hood to do this.

 

you can replace it if you want, but normally the master cylinder is one of those just replace when it breaks. personally id remove the lines since you would have to bend the lines a bit to work the booster out. you may end up doing more damage than its worth in time saved.

 

I had to replace the booster on my 02 DCSB a month ago... it is very easy to do. I had a similar whine and the booster would immediatly loose reserve vacuum when the motor shut down. When the motor was running and you clamped the booster vacuum line the idle was noticably smoother. The one warning that I can give is to make sure that the master cylinder to booser seal is put on the master cylinder BEFORE you slide the master cylinder back into the booster otherwise you will damage it and still have a issue. I would replace the booster to firewall seal also to prevent water from getting into the cab when it rains.

 

I'm with @paranoid56 - it adds time to figuring out a solution when people throw random answers shooting from the hip. I know you were trying to help so it's all good. Have a good day!

 

it can leak into the booster, also check the carpet on the inside to see if its wet. if you are loosing that much fluid its going somewhere lol also what year? might be a abs issue

 

Going into the booster. It will damage the booster diaphragm eventually. Unbolt master cylinder and pull it away from booster it will be wet on the piston area.

 

I've seen it many times where the master cylinder leaks into the booster. Sucks and can be expensive but it's more common than you would think.

 

yep. You can try and remove booster and wash it out with some brake clean and dump it out.