# MK4 - Losing brake fluid



## xxfmulder (Jun 6, 2001)

2001 GTI VR6
This past week, my "low brake fluid" warning light came on. I checked the reservoir, it was a little low. I added some DOT 4 fluid, and recapped the reservoir. 
A few day later, the light came on again. Sure enough, the fluid level was low. I added a little more fluid. 
Now the light is on again. I looked at every caliper and there are no obvious signs of leakage. Everywhere I could see under the reservoir looked clean and dry as well. There are no puddles forming under the car. Where the hell is the brake fluid going??
Is there some chamber in the brake booster that the master cylinder can fill if leaking?


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## Banditt007 (Oct 23, 2002)

*Re: MK4 - Losing brake fluid (xxfmulder)*

if the seal fails, where the master cylinders push rod goes into the brake booster...the brake boosters vacuum will suck the fluid out of the master and deposit it in the bottom of the brake booster. def follow each line from the master cylinder all the way to the caliper. if no leaks found this is most definitly where you are losing it from. turn the car off, and remove the vacuum line that attaches to the brake booster. look in there w/ a flash light...better yet stuff something in there line string or a coat hanger to get to the bottom of it, pull it out. everything in there should be bone dry. if its not that seal on the master clylinder went and you need a new master cylinder/rebuilt one. currently i am unaware of any master cylinder rebuild kits available.


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## xxfmulder (Jun 6, 2001)

*Re: MK4 - Losing brake fluid (Banditt007)*

Does the brake booster need to be replaced as well if it did get filled up with brake fluid?


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## Banditt007 (Oct 23, 2002)

*Re: MK4 - Losing brake fluid (xxfmulder)*

nope dosent need to be replaced. just syphon out the brake fluid that is collected in it.


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