Brake Booster and CIS

[jcc911]

Where does the brake booster hose go on a CIS system.
On the Drivers side of the Air box?
What else attaches there, a check valve or something?
Thanks.

[Gunter]

Originally Posted by jcc911

Where does the brake booster hose go on a CIS system.
On the Drivers side of the Air box?
What else attaches there, a check valve or something?
Thanks.

Drivers side of airbox but there are differences depending on the year/type.

By all means, do not tell us what year/type you have.

[jcc911]

78 SC, thought that was visible in my signiture

Thanks Gunter

[jcc911]

Anyone have a pics or two of their 78 CIS where the booster hose goes. Thanks

[Gunter]

On a '78-'79 CIS, the vac hose for the Brake Servo is connected to a nipple coming out of the airbox on the driver's side.
Should be a short steel nipple threaded into the airbox.
The hose clamps on to the nipple, very simple.
If the old hose is too short, or brittle, use a new one.

[jcc911]

Gunter, thanks for the info. Would you happen to know wht athe part nuber is?

I have read a lot of discussion about the booster needing vacuum above and below the TB in order to work properly. Is this the case for the 78?
If so, how would the one connection with the nipple accomplish this?

Thanks Again for your help!!!

[Gunter]

Part number for the steel nipple would be available on Pelican Parts list or call them.
With '80-'83 years, the vac was indeed taken from both top and bottom of the throttle plate simultaneously ending up in a Y-connection single hose to the Servo.
I have experience with both versions and cannot tell the difference; works fine either way IMHO.

[jcc911]

So, i found three possible parts in the catalog. What is the difference between 930-110-357-00, 911-125-341-01, and maybe 90511672500?

[Gunter]

930-110-357-00, 911-125-341-01 look the same; one is a lot cheaper than the other.
It's a mystery; I don't know.
Maybe order the one for $8.- and try?
Do you see the threaded opening on the left side of your airbox?

[boyt911sc]

Originally Posted by jcc911

Anyone have a pics or two of their 78 CIS where the booster hose goes. Thanks

JC,

Do you still need pictures of the brake booster vacuum line routing? PM me if you still want them. Thanks.

Tony

[jcc911]

OK, this is what I found out. 911-125-341-01 is for pre 80, but is list for cars with Sportomatic and I would need 911-125-341-02 (not sure why they would be different) the other 930-110-357-00 is for '80-83 cars.
Of course the one I would need is the most expensive, so I called the local P-car dealership and they said both of those parts have to be ordered from Germany, however the one i need is not available.
So my thought would be to try the other. Thanks for your help...

[boyt911sc]

Originally Posted by jcc911

Anyone have a pics or two of their 78 CIS where the booster hose goes. Thanks

The braided vacuum line connected to the air box (driver-side):


Long vacuum hose going through the engine bay inner section:


Vac hose connected to the steel tube going thru the tunnel:


The other end of the steel tube (vac line) comes out in the front hood near the brake booster. HTH.

Tony

[jcc911]

Tony thanks for the pics!!! Just what I needed. Now to find the right part...

[1982911SCTarga]

With '80-'83 years, the vac was indeed taken from both top and bottom of the throttle plate simultaneously ending up in a Y-connection single hose to the Servo.

Can anyone explain why the factory went to this approach? I'm putting all this stuff back on my cabriolet's engine (it's much nicer reassembling clean components rather than disassembling filthy parts) and I'm curious about the later SCs' double-vacuum connection.

The brass, U-shaped and oddly plumbed part allows for vacuum to be drawn by both the airbox and the upper throttle body (above the throttle body plate). Does the upper throttle body connection allow for more/better vacuum at idle or is the reverse true?

Brian