Ramp

While sorting/cleaning stuff, I found the 4 way vac splitter near the brake booster with one line plugged and the second line to what I believe is the HVAC feed (black line on firewall) disconnected. The third line runs to the one-way check valve and to the booster. The fourth line runs to a "Y" splitter under the brake cylinder and each of those lines (1 black and 1 white) go through the side wall and disappear.

I've gone through the threads and am still unsure on a few things as there are variations.

1. Is the plugged line supposed to be ? I don't see anywhere else it should go.
2. Where do the lines from the Y splitter go ?
3. Confirm the black line on the fire wall is the HVAC vac feed ?
4. It seems that some of the lines (or splitter) have shrunk and I cant have both the "Y " splitter and the HVAC line both connected to the 4 way. Will the LAPS have small vac line parts so I can splice some extra length in ? Or, should I just order a vac kit with new check valve and start replacing what I can now or wait until I can do the whole job at once ?
5. The one way check valve appears to work but how much effort should there be to open the valve (mouth test )





Thanks

The Forgotten On

The plugged line is a vacuum test port, leave it alone for now.

The Y goes to the cruise control and vacuum reservoir located in the left fender well.

The black line is indeed the feed for the HVAC system.

The rubber vacuum lines are 3 or 4mm and you can find it just about anywhere, the hard vinyl lines are more difficult to find.

The 1 way valve should require little to open, if it is hard to blow/suck through or make a buzzing noise, replace it.

Ramp

10 minutes for an awesome response. Thanks ! -- Now I should be able to trace the cruise and reservoir lines since I know where they are leading !
I think 1/8" vac hose should work for a temp patch.
The check valve definitely sounds like a horn when forcing air through and needs more than a gentle blow/suck. (No comments )
Will order a new one.

So, is the plugged port used to plug in a vac gauge and test this section of the vac system ? Haven't done that before but sounds like an easy thing and would require buying a vac gauge - always looking for an excuse to add tools.

Ramp

I found this pic in the section from John Pirtle and thought I would repost as it's very useful. The line that goes to the intake flap actuator I assume is the "flappy" issues people discuss on the later cars. On my 86.5 that line is simply plugged.

Ramp

The Forgotten On - So I ordered the wrong parts. The parts I ordered are 4 way # 117-078-00-45, Y splitter # 928-110-27-3-00 and the check valve #843-820-675
The 4 way and y fitting are clearly much larger diameters and not the right parts. The check valve looks right but it is much harder to suck/blow than the used original.

By chance do you know the part numbers ? I can't seem to find the correct parts in the Katalog.

Also, I noticed that you said to leave the vac test line pug alone for now. I assume you mean, no need to touch it unless I'm testing ? Or, is there some other use for that line ?

Thanks

Mrmerlin

you will need the Y connector,
it will join the 3 lines next to the washer tank transport tube under the right fender,
you can replace this Y when you service the washer and fill tube,
you will be removing the metal collars that are rusting the washer fluid

Ramp

Thanks. I will add that to the list and keep the Y. Do you know what the correct part #'s are for the 4 way and Y near brake booster ? And, is the new check valve supposed to be hard to suck/blow through ? Maybe it will ease up over time.

bureau13

You may have heard this before, but the best way to ensure you get the right parts is to go through the dedicated 928 vendors like Roger at 928sRUs or Mark and Tom at 928 International. You tell them what you're doing, and what your car particulars are, and they'll put together a package. Don't go by their web sites, call or email.

Mrmerlin

What Jeff said ^^^^^
The blue valve is a one way valve and its hard to blow through BUT I would test it with a mytivac

Ramp

Yup, my mistake, I ordered from one of our vendors website without calling (although I did leave a note in the message section if they could confirm the correct parts). Still curious that the Y piece is for the washer tubes although it says vacuum line for the website description. But it's clearly not the vac line.

What would be the correct reading for the mityvac on the check valve ?

bureau13

You're not really looking for a reading at that point...you should be able to use the Mityvac to suck through it and it won't hold a vacuum from one side, and then from the other side whatever you pump it up to (within reason of course) it should hold it indefinitely. Also within reason...