Had my brake fluid changed yesterday and got a chance to watch it being done. He used about 1.5litres of fluid but a couple of times he had to let the air out because something went wrong.

as he finished noticed a small puddle of fluid underneath my car. checked the resovoir and seemed ok. But he said to keep an eye on it as thinks the master brake cyl could be bad.

is this viable? and why would the cylinder be faulty?

It's possible. If you have one, mark the fluid level on the reservoir with a chinagraph pencil, so any loss of fluid will be very obvious.

but a couple of times he had to let the air out because something went wrong.

as he finished noticed a small puddle of fluid underneath my car.

If it has leaked out enough to go onto the ground it will probably have run down the front of the vacuum servo at the back of the cylinder. Apply the brakes mega hard for a minute with the engine running (probably best to do this while stationary, lol) then check for leaks by running your hand underneath the cylinder at the back.

The "air" thing concerns me. How were they bled? Was it done with proper garage equipment sucking brake fluid through the bleed nipples? Did he forget to top up the master cylinder reservoir? If so I wonder about the ABS (I know little more about ABS than air in the pump isn't good and needs diagnostic equipment to bleed it).

If it has leaked out enough to go onto the ground it will probably have run down the front of the vacuum servo at the back of the cylinder. Apply the brakes mega hard for a minute with the engine running (probably best to do this while stationary, lol) then check for leaks by running your hand underneath the cylinder at the back.

The "air" thing concerns me. How were they bled? Was it done with proper garage equipment sucking brake fluid through the bleed nipples? Did he forget to top up the master cylinder reservoir? If so I wonder about the ABS (I know little more about ABS than air in the pump isn't good and needs diagnostic equipment to bleed it).

hi, thanks for the advice.

where can i locate the master cylinder? is this something i can check myself

i think it was proper garage eqiuipment. best i can describe it is it was a small pot with a lid on the top and attached to it was a hose which was sucking the old fluid out.

the fluid in the resoivoir seems ok so far...

Edited 30 April, 201016 yr by newskoda