Brake Failure

**steve50** · 23-10-2013,11:13 PM

hi chaps, got into car today and brake pedal went to floor, checked under car and no leak. but master cylinder was empty, called out rac diagnosed master cylinder gone so took me to my garage who refilled the master cylinder and got brakes working. could not find leak at all, has anyone had this happen to them, am pretty worried about driving the car as the fluid had to go somewhere, could it have seeped into servo unit? any suggestions gratefully accepted
cheers
Steve

**RichardSEL** · 24-10-2013,06:57 AM

This must be found without driving!
Just topping up the resovoir and sending you on your way isn't a good idea especially if RAC diagnosed faulty master cylinder. Go somewhere else, get confirmatory diagnosis
What year? What dash lights have you?
When was brake fluid flush and re-fill last done?
VW say should be every two years with fluid meeting spec VW501 14-B 000 750. Think there's VW504 now

Let us know how you get on?

**Doctle Odd** · 24-10-2013,08:14 AM

I'd have to agree with Richard, don't drive this car or use that garage again. The car is potentially lethal and should have spent a few hours in a lift

mjhamilton · 24-10-2013,08:42 AM

As above - brake fluid doesn't magically disappear - it has to be going somewhere

For the reservoir to empty there must be a major leak with fluid being expelled on every pedal press

Don't drive it and get someone to look at every part closely to find the root cause before it goes back on the road

DSG4ME · 24-10-2013,01:51 PM

Is the clutch on the same circuit?

If it is you could have a leak in the gearbox causing the loss, simply look under the car where the box meets the engine for excess drips of oil.

**size12** · 24-10-2013,02:05 PM

Also check all the brake pads, if they are all on the limit that could account for the fluid loss.

**martin1810** · 24-10-2013,02:30 PM

The fluid is probably in the clutch now. Common fault on 2.0 engines.

**Doctle Odd** · 24-10-2013,02:33 PM

New avatar? Every time I saw the old one I could hear "bi*ch be cool"

Originally Posted by DSG4ME

Is the clutch on the same circuit?

If it is you could have a leak in the gearbox causing the loss, simply look under the car where the box meets the engine for excess drips of oil.

**steve50** · 24-10-2013,08:02 PM

thanks fellas, it was in the air for an hour but could not find any leak then drove around for half an on industrial estate roads went back in and fluid was in at same level so mechanic was stumped, anyway off to another garage tomorrow,
Didn't know fluid served both parts, how come clutch is still working?

**zollaf** · 24-10-2013,08:11 PM

the clutch will take its fluid from about halfway up the brakes fluid resevoir, so if the clutch does fail and empty its fluid it won't totally empty the brake resevoir, so i think you can rule out the clutch. this leaves the brakes. the clutch will still work because there is still fluid in the pipe feeding the master cylinder for it. if there is no fluid leak to be seen, then it must be the master emptying itself into the servo. the fluid can't go anywhere else without making a visible mess. the master cylinder needs removing and the servo should also be replaced rather than just being drained.
i am suprised the mechanic was stumped. would he have been mystified if you had caused a fatal crash due to his incompetence ?