Two Rubber Hoses

[Melbo]

I have two rubber hoses going through what I would call the "firewall". One hose is connected to a vacuum switch (or air switch) activated by the
brake pedal. I'm sure that is for the cruise. The other hose is cut off under the dash and also cut off in the engine compartment. I was going to
remove it and use the opening for routing wires from the engine compartment to the dash. If that hose served a valuable function and should be
replaced and connected it would be helpful to know how and where it should be. If it is unnecessary I will remove it. Hard to guess what is what
from October of 1973 and who knows how many owners and friends of owners that changed and modified things before I started.

TIA

Melbo
--
Albuquerque NM Bus Conversion 1978 MCI 1973 GMC

 

[RF_Burns]

Could be for the air compressor for the suspension. The pump was mounted up front under the driver on early models. A hose was ran inside from the
air input of the compressor to draw clean air into the compressor.

Just my guess

--
Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that

 

[Matt Colie]

Melbo,

Our 73 is pretty much intact, even the TIC valve was functional until recently. If you describe specifics of the location of this other hose, I will
see if I can match it up later today.

Matt
--
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit

 

[Melbo]

Bruce

I do believe that you have answered my question. That makes sense because that is where the old air compressor was.

Matt

I'm sure you can confirm that as well.

I no longer use the original air pump so I can do what I want and put some wires through that opening.

Thank You

Melbo
--
Albuquerque NM Bus Conversion 1978 MCI 1973 GMC

 

[RF_Burns]

Matt,
I can usually follow your acronyms or Google them. You got me on the "TIC" valve though. Google didn't come up with anything that makes sense in
this context.

Can you help me out with what a TIC valve is? I suspect its the cruise release valve on the brake peddle but I can't figure out the acronym.

Inquiring minds want to know!

Thanks

--
Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that

 

[marsh wilkes]

Had me going too. I'm thinking it must be like thermal idle control.
I remember my 70 GTO 455 would speed up the idle cyclically while idling
with the AC
running on a hot day, at the time I didn't know for sure what it was or how
it was done.
If I have it right now, it's a temperature controlled vacuum leak that revs
the engine, fan,
water pump to prevent over heating. I'm sure Matt or someone will speak up.

Marsh Wilkes
Perry Fl

-----Original Message-----
From: Bruce Hislop via Gmclist
Sent: Saturday, February 20, 2021 11:46 AM
To: gmclist
Cc: Bruce Hislop
Subject: Re: [GMCnet] Two Rubber Hoses

Matt,
I can usually follow your acronyms or Google them. You got me on the "TIC"
valve though. Google didn't come up with anything that makes sense in
this context.

Can you help me out with what a TIC valve is? I suspect its the cruise
release valve on the brake peddle but I can't figure out the acronym.

Inquiring minds want to know!

Thanks

--
Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that

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[Matt Colie]

I am at a loss here to know what happened to the reply I wrote last night.

TIC is some OEs label to Thermal Ignition Control. GM calls this a Thermal Vacuum Switch. This is one of many vocabulary problems. When I ran a
contract lab that did testing for everybody I had a translation over my desk so I could get the right acronym for which ever client that I happen to
be talking to right then.

I also wrote for Maelbo that I had four such penetrations for different services. As of this morning I would again have to go out in the cold to look
at and determine what each is for, Air Pump, Cruise breaker, and HVAC are all that I can remember as I write.

Matt
--
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit

 

[john r. lebetski]

But TVS or TIC would not pass through firewall. .
--
John Lebetski
Woodstock, IL
77 Eleganza II

 

[Ken B]

Engine vacuum to the heater control might pass through there.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana

 

[johnny]

TLAs can be troublesome if everyone doesn't use the same argot.

--johnny
--
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell