Hi all, patient is a 60 Beetle, unmodified.

Car has recently had a lot of mechanical work including brake work, such as cleaning up the master cylinder, full bleed, and clean of the reservoir. Has driven less than 100 k's and been laid up due to other issues (non-related to brakes). Car hasn't moved for weeks and on Thursday I found a puddle under the car of brake fluid, dripping quickly. Investigation showed the fluid has come out of the top rubber plug where the reservoir tube comes in to the top of the master cylinder.

The plug doesn't seem to fit right, just loosely sitting on top. I am told they just clip in without much force, I thought they would have to sit fairly firm as they would hold pressure of the fluid in the master cylinder?

I know I am up for a brake bleed now once I get the plug to hold. Is it as simple as getting a new plug to just sit in the receptacle? I really would have thought it would need some degree of tight fit to hold there.

Not sure why this one popped after not moving for weeks, any ideas?

Thanks.

put the rubber plug in the hole first they should be tight and hard to push right down into place

then fit the metal brake tube into the rubber push all the way in then pull back slightly

They are a push fit into the MC. Make sure have the right size. There are are two different ones. The difference between them is the size of the hole for the tube from the fluid reservoir. Early is small and later is large.

Thanks all, I've had more of a fiddle with it today. It seems firmly seated in the hole but the top is spongy and definitely covered in fluid on the outside of the rubber. If the plug is seated properly, then I suppose it can only be a leak in the plug itself, i.e. a split or break in the rubber plug? I'll look to renew the plug and get the brakes bled, hopefully after this we'll be good.

Thanks.

If the plug is SPONGY then get a new one its had its day