Help! What is this line? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

LDO · 06-01-2023, 08:52 AM

Can someone ID this line and where it should be connected?
1985 C10
Has AC
Looks to be some sort of AC vacuum control line or something.
Comes out of firewall and routed towards driver side.

**kwmech** · 06-01-2023, 11:28 AM

Goes to the vacuum ball, from the ball it goes to manifold vacuum with a check valve. That vacuum lines goes inside to the heater and AC controller for the hvac doors. Should be going not too far from where it is at the moment. The ball mounts to the evap box. I can see the feed line to the ball just below your thumb with the check valve

LDO · 06-01-2023, 11:47 AM

Quote:

Originally Posted by kwmech

Goes to the vacuum ball, from the ball it goes to manifold vacuum with a check valve. That vacuum lines goes inside to the heater and AC controller for the hvac doors. Should be going not too far from where it is at the moment. The ball mounts to the evap box. I can see the feed line to the ball just below your thumb with the check valve

Thank you!!

So if I were to get a new 'T' or something, Could I connect it somewhere in the red circle?

**kwmech** · 06-01-2023, 01:26 PM

Where's your vacuum reservoir? That's where it's supposed to go, but yeah you can, but as soon as you shut the engine off nothing inside will operate vacuum wise

LDO · 06-01-2023, 01:48 PM

Quote:

Originally Posted by kwmech

Where's your vacuum reservoir? That's where it's supposed to go, but yeah you can, but as soon as you shut the engine off nothing inside will operate vacuum wise

I will look today. I sold this truck a few years ago and just recently bought it back so I'll take a look.

87chevy.com · 06-01-2023, 07:21 PM

if you dont use a vacuum reservoir, it will be like my truck...., full throttle, a/c goes to floor

one day I will put a reservoir in there

**kwmech** · 06-01-2023, 11:17 PM

Quote:

Originally Posted by 87chevy.com

if you dont use a vacuum reservoir, it will be like my truck...., full throttle, a/c goes to floor

one day I will put a reservoir in there

Yep, there is that also that slipped from my mind

Dead Parrot · 06-02-2023, 07:59 AM

Bottom of a vacuum pot where the line goes. 2nd larger line goes to a manifold vacuum source. This one is next to the AC housing on the firewall. Some are spherical.

**TKCR** · 06-02-2023, 10:56 AM

Pics should help

LDO · 06-02-2023, 07:29 PM

Thanks for everyone's help. I started digging around and found the T-connection where this is supposed to be hooked up to. Comes from the vacuum reservoir right behind my jack on Driver's side fender.

06-01-2023, 08:52 AM	#1
LDO Registered User Join Date: Feb 2011 Location: Senatobia, MS Posts: 1,291	Help! What is this line? Can someone ID this line and where it should be connected? 1985 C10 Has AC Looks to be some sort of AC vacuum control line or something. Comes out of firewall and routed towards driver side. Attached Images __________________ Once a Marine, always a Marine! My (Her) 57 Build "Beverly" My 66 Build "Betty" My 85 C10 "Old Blue" Help Me Find "Old Blue" OLD BLUE PART II

06-01-2023, 11:28 AM	#2
kwmech Senior Member Join Date: Mar 2003 Location: Colfax-California Posts: 8,389	Re: Help! What is this line? Goes to the vacuum ball, from the ball it goes to manifold vacuum with a check valve. That vacuum lines goes inside to the heater and AC controller for the hvac doors. Should be going not too far from where it is at the moment. The ball mounts to the evap box. I can see the feed line to the ball just below your thumb with the check valve

06-01-2023, 01:26 PM	#4
kwmech Senior Member Join Date: Mar 2003 Location: Colfax-California Posts: 8,389	Re: Help! What is this line? Where's your vacuum reservoir? That's where it's supposed to go, but yeah you can, but as soon as you shut the engine off nothing inside will operate vacuum wise

06-01-2023, 07:21 PM	#6
87chevy.com BMW & ASE Master Certified Join Date: Feb 2004 Location: Houston, Texas Posts: 1,255	Re: Help! What is this line? if you dont use a vacuum reservoir, it will be like my truck...., full throttle, a/c goes to floor one day I will put a reservoir in there __________________ 1987 Silverado - L83 5.3 w/ 6L80e ,A/C,P/W,P/L,TILT, HID projectors, Wilwood C-10 Pro Spindles w/ 2018 silverado front brakes & C-5 Corvette Rear Disc Brakes 1999 BMW 528i - 5.7 LS1 w/ 4l60e, Ford 8.8 IRS w31 spline posi & FX-r projector retrofit New project: 2006 BMW x5 6cyl AWD to L83 6l80e 4wd to 2WD / RWD A poor man buy's it twice finally got my domain name back, 87chevy.com.... site rework in progress

06-02-2023, 07:59 AM	#8
Dead Parrot Registered User Join Date: Aug 2012 Location: Oklahoma City, OK Posts: 2,477	Re: Help! What is this line? Bottom of a vacuum pot where the line goes. 2nd larger line goes to a manifold vacuum source. This one is next to the AC housing on the firewall. Some are spherical. Attached Images

06-02-2023, 10:56 AM	#9
TKCR Senior Member Join Date: Oct 2014 Location: Ohio Posts: 6,858	Re: Help! What is this line? Pics should help Attached Images __________________ FB Page for my Seats Belts https://www.facebook.com/73-87-Chevy...9439407476735/ Restoring Seatbelts: http://67-72chevytrucks.com/vboard/s...d.php?t=809750 SOLD My 86 Build:http://67-72chevytrucks.com/vboard/s...d.php?t=654972 Past Restored Bench Seats:http://67-72chevytrucks.com/vboard/s...d.php?t=715398 PayPal link to pay for your items: https://www.paypal.me/TKCR

06-02-2023, 07:29 PM	#10
LDO Registered User Join Date: Feb 2011 Location: Senatobia, MS Posts: 1,291	Re: Help! What is this line? Thanks for everyone's help. I started digging around and found the T-connection where this is supposed to be hooked up to. Comes from the vacuum reservoir right behind my jack on Driver's side fender. Attached Images __________________ Once a Marine, always a Marine! My (Her) 57 Build "Beverly" My 66 Build "Betty" My 85 C10 "Old Blue" Help Me Find "Old Blue" OLD BLUE PART II



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