Vacuum pump suction readings.

I replied last night but it did not post.
There are thee fittings. Vacuum In,out and vent when off

I may have a bad actuator. It bleeds down vacuum.
I have no idea what to ask for for a replacement part or what it even looks like.
The B4 is not represented well on Youtube anymore. Looks like the B5 and on uses an electric motor.
Are there instructions anywhere on how to replace the part on the air box?

If three fittings, the vacuum will be blocked when the solenoid is off, and the circuit to the actuator will be vented to allow any vacuum in the circuit to disipate and the actuator to move back to fresh air.

If the solenoid is allowing vacuum to escape, then you should be able to get the actuator to move (all else being OK) if you bypass the solenoid and put vacuum directly to the actuator. If I recall, you have already tried this.

With a three ported solenoid, by design, your actuator should pull and hold vacuum with a mityvac - your description is that is not happening. based on that I would say you have a diaphragm or other leak in the actuator - I would start there.

I remember looking at mine when I had the B4, and it was tight against the right side sheet metal on the hvac box - I never removed mine.

Whole lotta work just for recirc huh?

Work? You betcha. I'm thinking the actuator is Kaput.
No idea how to remove/replace it.

Check my reply in your other related thread.

Pull knee bar out of the way or just slide the seat back as far as possible and contort yourself under there. Think of it being located where your hood release is but mirrored to the the right side. Philippe screw holds it in, behind it. Good luck if you got fat fingers,

Does anyone have the part number for the vacuum actuator? I'm coming up with nothing. I'm not even sure what the part is called by VW.

Rapidrob said:

Does anyone have the part number for the vacuum actuator? I'm coming up with nothing. I'm not even sure what the part is called by VW.

Click to expand...

VW calls it a 'vacuum unit' in the parts catalog but oddly enough they don't have a schematic with it shown, they just have a little notation for it where they have the part number for the flap.

I had a good one a while back but someone bought it. Who that was I don't remember.

Part # 191820677b

edit: now that I see the prices they charge I know why someone bought it...lol

Steve

Steve Addy said:

.

I had a good one a while back but someone bought it. Who that was I don't remember.

Part # 191820677b

edit: now that I see the prices they charge I know why someone bought it...lol

Steve

Click to expand...

Heyyyyyyyy Steve. . Actually never looked for new, easy enough to find them used.

Easy as in who has them used? I found a new one in Russia via Germany for much less less than the rip-off artiest here in the states.
Thanks for the part number and research. I appreciate it.

The forum. The guys parting out the many b4s

I'd imagine that any B4 or likely even A3s use the same actuator/solenoid.

-Todd

ToddA1 said:

I'd imagine that any B4 or likely even A3s use the same actuator/solenoid.

-Todd

Click to expand...

Unfortunately not, the Mk3 uses something different.

Looks like the cross-ref list is not long:

Eurovan 2.5 - 92-94
Eurovan 2.8 - 99-03
Eurovan 95-99, 04
Golf 89-92
Jetta 86-92
Passat 90-97
Corrado - all years.

I happen to get one because I replaced the complete heater box on my wagon, but they aren't easy to remove because of location.

Steve