Brake Servo And Brake Fluid

[WOO5IE]

I am monitoring the brake fluid level at the moment as during the cold period the other week the low level lamp came on.

The level wasn't particularly low but the fluid had been changed on the last service since I last looked. So I am not sure if it was a sticky float on the sensor due to cold weather. But on reading a few threads on here it seems that the fluid can get into the servo.
I have had a look at pictures of servos and I can't see how that can happen as the servo should be sealed. It's a vacuum that operates the master cylinder.

I have checked calipers etc but can't see any leaks. It the master cylinder was leaking I believe it would be seen on drivers carpet.

Brakes are working well and no reoccurrence since. I did top up the resovoir at the time and still monitoring level.

If the master cycling did leak can it get into the servo??

[Steve_D]

There are two possibilities here but both would involve a vacuum leak.

The actuating shaft of the servo comes through a seal on the servo casing. The shaft then goes into the bottom of the master cylinder. The other side of this seal is vacuum.

So for fluid to pass into the servo there would need to be a vacuum leak and a master cylinder leak or the vacuum leak is severe enough that it is pulling fluid past an otherwise sound seal on the master cylinder.

There are plenty of other places where you could be getting a leak. It could still be the master with it running down the casing of the servo and down into the footwell and carpet.
Bulkhead manifold...again leaking into footwell.

Steve

[Aussie John]

I've had this happen on a few cars over the years, a Cooper S [old mini] a DB6 Aston and a couple of others; a new set of seals in the servo solved the problem.

[Sardonicus]

The vacuum seal on these servo's are not available as a spare part and no matter how good/condition the servo push-rod seal is if you have a leaking master cylinder over time it will find its way into the servo chamber as brake-fluid has amazing searching properties and not exclusive just to the servo that TVR fitted to these cars, in fact you may show signs of paint stipping on the servo just under the master cylinder at 6 o,clock position but inverably most of the leaking fluid finds its way into the servo body helping to rot the base out made worse by the fact that brake-fluid is hygroscopic meaning its absorbs moisture an ideal combo for rust promotion