where is my brake fluid going?

[92EcoDiesel Jetta]

"it" is brake fluid, what we were talking about all along.

Now that you have pointed out the divot on the booster, I see what you mean that brake fluid (as well as air) would drain out the front of booster, after the booster is filled 1/2 way from a MC leak. I still cannot picture how a seal inside the booster would look like. Seems not possible.

As for the grommet, my ATE MC came with 2 grommets installed (for the reservoir- and it didn't leak) as well as a vacuum o-ring seal. I assumed the single grommet shown on the same page as the 1982 MC goes between the MC and the booster to provide a vacuum seal, not for the reservoir (where 2 grommets would be required). Was my assumption wrong?

Anyone else know anything about this? We are not getting anywhere. My 81 Rabbit pickup should have the same brake setup as the 82 Rabbits. I have not had to do any MC or booster work on mine yet. When I do, I will have a chance to have a look and maybe answer my questions.

When you say "it" could drain from the booster what do you mean?

 I believe that grommet is to seal around the reservoir,.. so yes I used it. Of course the rebuilt master cylinder had it's own grommet but I've heard of them leaking and that was the case with the new grommets on my rebuilt master,... so I reused the ones from the old master.

  The top link to the partsjerk booster shows you real well how the seal looks inside the booster and it even has a little divot for the brake fluid to leak down the front of the booster if the master starts leaking. Kind of hard to get an o-ring to seal with a deep dent where it rides.
 Oh if you send a postal money order to partsjerk they will wait 3 weeks before sending your part,... that info isn't on their website.

[vanbcguy]

The booster is sealed internally, it does not rely on the MC to booster junction for sealing in any way. The seal there is a dust/moisture seal only.

Sent from my XT1097 using Tapatalk

[fatmobile]

 As I see it that divot would keep fluid from leaking into the booster by allowing it to drain down the outside.
 I think assuming your '81 is the same setup as the '82 might be reaching.

 I've already pointed out; I think your assumption that the gommet goes between the master and booster is wrong. Again, I think it goes between the resevoir and master.

At some point; some of the boosters were set up so any fluid leaking from the back of the master doesn't fill the booster,... it runs down the front.
 The lack of o-ring groove in the master as well as no good place to seal against the front of the booster,... in items you linked,  to confirm this.