Vacuum pump question 1985 Jetta Diesel

[dyoungen]

I think I"m working with the vacuum pump and I have a question. First off I found what I think is the vacuum pump and connected to it is a round plastic connector that has two connectors coming off of the side. One is plugged and the other was connected to a line that went nowhere.  The connector at the top goes to the brake booster. I found a yellow line that comes from the firewall, that was laying next to the open line. They fit like they were supposed to be connected. The two side connectors broke off when I tried twisting the plastic fitting. Do I need the plastic fitting or can I just make up a fitting that all of the vacuum will go through? Also, does this mkII have a radiator drain?

[rallydiesel]

You can make your own fitting. Unless you have cruise control, the only vacuum a mk2 uses is the brake booster and the hvac blower vent solenoids. There is no radiator drain on a mk2. You just have to pull off the lower hose and mop up the coolant that goes everywhere BUT the drain bucket.

[bajacalal]

Just general advice ~ never ever take out a radiator drain plug. 9 times out of 10 these days they are plastic and will break in two, then you have to fish out the pieces and find a new drain plug which often are different thread sizes on aftermarket radiators than the original one. Just save your self the headache (besides the mess) and pull the lower hose.

[neimis]

The round plastic connector with two connectors coming off the side is a vacuum check valve. It becomes brittle with age and the nipples snap off very easily, as you found out. You can make your own, just connecting up the lines, and it will work, but the original has a one-way valve in it. I would guess that the purpose of the one way valve is for the brake booster to retain built up vacuum.

If you want to replace it, it comes with the brake booster line molded on, you just pull it out of the brake booster grommet and push the new one in.

You can check the operation of the valve by plugging the two side connectors and blowing into it - air should pass one way but not the other.