I Dunno What It Is - Page 2 - The 1947 - Present Chevrolet & GMC Truck Message Board Network

R.L. · 02-25-2009, 07:40 PM

Yes it does look like a fill cap but what kind of clearance do you have with the seat installed to fill it? If it back blow ed you'd have a mess in you're cab and if it vented it would smell oily, strange.

69halfton · 02-25-2009, 08:08 PM

OH BOY. rare factory option!!

1 of a kinda.

that vent was originally hooked up to a large air filter, with a pump driven by the engine. it pumped freash air into the cab constantly, it was designed for the president of the time, for if he was in some sort of gas attack.

that was his gas-attack-escape-vehicle.

they made it a truck so that it blended in

actually, i have no clue what it is..looks like a vent of some kind that needed to be vented,but couldn't have water go in. easiest way to tell if its a vent or cap is to pull it off and look..

crazy longhorn · 02-25-2009, 08:16 PM

Quote:

Originally Posted by big_al_71

I think it is to let the farts out of the cab without putting the window down, see the location?

Rigging ingenuity at it's best!!!!

LOL! Thats what I thought.....its a "Fart dissapator"

drivethechevy · 02-25-2009, 08:32 PM

maybe it was the fill cap for a full frame or boxed frame gas tank, i have seen a motorcycle where the frame was used as another gas tank, id say its probly nothing factory

lofly'a · 02-25-2009, 09:23 PM

"Logic" says this is a fill tube, and i say "logic" because logically you don't vent into the passenger cab area. it most likely is a fill tube for a PTO that is/was mounted to a gearbox attached to the output shaft of the transmission. not positive on this application but i have seen this before for a PTO setup.

**James Pierce** · 02-25-2009, 09:37 PM

The larger trucks had vac brakes and a tank on the frame and the vent was in the
cab to keep dust and moisture out of the system. You could hear air moving if the
truck was parked and you pushed the brake pedal. Retired rancher and owned one
a GMC.

**special-K** · 02-25-2009, 10:34 PM

^I`m buyin`it! That makes sense to me.The last C/40-up brake system suggestion got me going before.i`ve only seen a couple of those 11,000#+ C/30s and just enough to notice the wheels.

cooldudecoco · 02-25-2009, 10:51 PM

there is alot of space next to the gas tank ,, not what a stock gas tank looks like

70 Suburban · 02-25-2009, 11:49 PM

ok I looked at every page of the fsm.. I found it. It is a fresh air breather for hydraulic over vacuum brakes. another tube went from there to the passenger side where a vacuume pod was mounted. If i have time ill try to scan it for you.

**special-K** · 02-26-2009, 06:41 AM

Thanks 70 Suburban!I thought it looked factory.This was one special truck.I never saw too many of those beefed-up 1 tons and this one was a Custom Cab (bright mouldings at the glass) and had air conditioning.I`m going to check the SPID to see what else it had.I got it because it was the holy grail for a K/20,which I had three of,with high hump,a/c,and cab lights.

I removed the gas tank and cleaned it.It`s just set in there,not mounted.

old Chevy guy · 02-28-2009, 12:09 AM

Quote:

Originally Posted by old Chevy guy

What happend to the rest of the truck? could it be some kind of a vent or a breather for a vac booster under the cab.I saw a 3500 gmc once that was supper HD it had 18" wheels with a big bolt pattern like a c 50 or 60 and it had a brake booster under the cab on the frame like my old c60.I dont know why it would need to vent inside the truck though,just throwing it out for consideration.

Looks like we have a winner! LOL

70 Suburban · 02-28-2009, 12:56 AM

lol i was only conferming your original statment

**passthebuck** · 02-28-2009, 12:58 AM

It's a PCV valve - Positive Cab Ventilation!

arkie726 · 02-28-2009, 01:26 PM

Its the HydraVac vent, the cab is from a 1 1/2 truck or so.

**rockc** · 02-28-2009, 07:54 PM

Saw one on a 69 GMC 5500 truck today at an auction. It looked like it was for the brake booster used as a breather. The booster was mounted right below the cap on the frame and only the master cylinder was up under the hood. Tried to take pictures of it with cell phone but they didn't come out very good.

LUV2XCLR8 · 02-28-2009, 07:57 PM

The PO ate Mexican everyday?

(Cab Vent)

**john** · 03-02-2009, 02:03 PM

Quote:

Originally Posted by 70 Suburban

ok I looked at every page of the fsm.. I found it. It is a fresh air breather for hydraulic over vacuum brakes. another tube went from there to the passenger side where a vacuume pod was mounted. If i have time ill try to scan it for you.

There are pics in this thread, posts # 33- 34.
http://67-72chevytrucks.com/vboard/s...=318118&page=2

thirdstreettito · 03-02-2009, 02:20 PM

**john** · 03-02-2009, 02:39 PM

And the booster. Pic from 71 c30 build.

**special-K** · 03-03-2009, 10:48 AM

There goes my theory it was a special 1969 Woodstock Edition that came with a hippy camper built on it and this was the driver`s air supply from the back.

69Warrior · 03-03-2009, 11:54 AM

Quote:

Originally Posted by big_al_71

I think it is to let the farts out of the cab without putting the window down, see the location?

Rigging ingenuity at it's best!!!!

was gonna say the same thing...good stuff right there

LOW DOUGH · 03-03-2009, 12:06 PM

it is a kanewter valve. don't know how you would spell that.

02-25-2009, 07:40 PM	#26
R.L. Registered User Join Date: Sep 2008 Location: Mobile, Al. Posts: 687	Re: I Dunno What It Is Yes it does look like a fill cap but what kind of clearance do you have with the seat installed to fill it? If it back blow ed you'd have a mess in you're cab and if it vented it would smell oily, strange.

02-25-2009, 08:08 PM	#27
69halfton Registered User Join Date: Apr 2007 Location: King City, Ontario, Canada Posts: 974	Re: I Dunno What It Is OH BOY. rare factory option!! 1 of a kinda. that vent was originally hooked up to a large air filter, with a pump driven by the engine. it pumped freash air into the cab constantly, it was designed for the president of the time, for if he was in some sort of gas attack. that was his gas-attack-escape-vehicle. they made it a truck so that it blended in actually, i have no clue what it is..looks like a vent of some kind that needed to be vented,but couldn't have water go in. easiest way to tell if its a vent or cap is to pull it off and look.. __________________ - Jason If you can turn, Youre not going fast enough. Favorite caption: first car to 200 mph in the 1/4 mile, no parachute, drum brakes all the way around.. ..back when men were men. Last edited by 69halfton; 02-25-2009 at 08:08 PM.

02-25-2009, 08:32 PM	#29
drivethechevy Registered User Join Date: May 2007 Location: Buffalo MN Posts: 606	Re: I Dunno What It Is maybe it was the fill cap for a full frame or boxed frame gas tank, i have seen a motorcycle where the frame was used as another gas tank, id say its probly nothing factory __________________ Trial and Error, its expensive but its a mistake i most likely wont make again 1971 chevy k10 custom deluxe http://67-72chevytrucks.com/vboard/s...d.php?t=341257 1968 chevy k/10 fleet http://67-72chevytrucks.com/vboard/s...d.php?t=334731 1948 desoto custom coupe fluid drive(family heirloom)

02-25-2009, 09:23 PM	#30
lofly'a Registered User Join Date: May 2000 Location: Alexandria, LA 71301 Posts: 1,451	Re: I Dunno What It Is "Logic" says this is a fill tube, and i say "logic" because logically you don't vent into the passenger cab area. it most likely is a fill tube for a PTO that is/was mounted to a gearbox attached to the output shaft of the transmission. not positive on this application but i have seen this before for a PTO setup. __________________ -02 avalanche (daily driver) -66 gto ragtop 389/400 (garage queen, hand-me-down from dad) -72 Tribute Trans Am (6.0LS/T56 6-speed) in progress -2003 YUKON (Wife's) -71 gmc swb fleet (current project, gonna shave everything, bags, stuff w/ 20's, gen III powertrain) -48 3100 SWB - 12/31/23 LONG TERM Project

02-25-2009, 09:37 PM	#31
James Pierce Registered User Join Date: Feb 2009 Location: Cle Elum, Washington Posts: 163	Re: I Dunno What It Is The larger trucks had vac brakes and a tank on the frame and the vent was in the cab to keep dust and moisture out of the system. You could hear air moving if the truck was parked and you pushed the brake pedal. Retired rancher and owned one a GMC. __________________ cascadeheavychevy 67 C10 327 4speed 69 C20 350 4WD 4speed 69 C20 350 4WD 4speed 69 C20 350 4 soeed 69 C20 CST 350 Auto 70 C10 307 4speed 71 GMC Supr 350 Auto 70 C10 350 Auto 67 CST 327 Auto

02-25-2009, 10:34 PM	#32
special-K Special Order Join Date: Nov 2004 Location: Mt Airy, MD Posts: 85,863	Re: I Dunno What It Is ^I`m buyin`it! That makes sense to me.The last C/40-up brake system suggestion got me going before.i`ve only seen a couple of those 11,000#+ C/30s and just enough to notice the wheels. __________________ "BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~

02-25-2009, 10:51 PM	#33
cooldudecoco Registered User Join Date: Mar 2008 Location: baltimore Posts: 136	Re: I Dunno What It Is there is alot of space next to the gas tank ,, not what a stock gas tank looks like

02-25-2009, 11:49 PM	#34
70 Suburban Rods Join Date: Nov 2002 Location: Bryan, TX Posts: 1,398	Re: I Dunno What It Is ok I looked at every page of the fsm.. I found it. It is a fresh air breather for hydraulic over vacuum brakes. another tube went from there to the passenger side where a vacuume pod was mounted. If i have time ill try to scan it for you.

02-26-2009, 06:41 AM	#35
special-K Special Order Join Date: Nov 2004 Location: Mt Airy, MD Posts: 85,863	Re: I Dunno What It Is Thanks 70 Suburban!I thought it looked factory.This was one special truck.I never saw too many of those beefed-up 1 tons and this one was a Custom Cab (bright mouldings at the glass) and had air conditioning.I`m going to check the SPID to see what else it had.I got it because it was the holy grail for a K/20,which I had three of,with high hump,a/c,and cab lights. I removed the gas tank and cleaned it.It`s just set in there,not mounted. __________________ "BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~

02-28-2009, 12:56 AM	#37
70 Suburban Rods Join Date: Nov 2002 Location: Bryan, TX Posts: 1,398	Re: I Dunno What It Is lol i was only conferming your original statment

02-28-2009, 12:58 AM	#38
passthebuck Sisyphus was my mentor! Join Date: Sep 2002 Location: Carleton Place, Ontario CANADA Posts: 984	Re: I Dunno What It Is It's a PCV valve - Positive Cab Ventilation! __________________ passthebuck #5642 -TWO 1967 GMC 910's. One with L6/3-on-the tree and the other with 355 w/435hp & a 700r4. -a 2013 Honda Civic as my "sensible" car

02-28-2009, 01:26 PM	#39
arkie726 Registered User Join Date: Sep 2008 Location: Lebanon, MO Posts: 48	Re: I Dunno What It Is Its the HydraVac vent, the cab is from a 1 1/2 truck or so.

02-28-2009, 07:54 PM	#40
rockc Registered User Join Date: Jul 2007 Location: SE WY Posts: 633	Re: I Dunno What It Is Saw one on a 69 GMC 5500 truck today at an auction. It looked like it was for the brake booster used as a breather. The booster was mounted right below the cap on the frame and only the master cylinder was up under the hood. Tried to take pictures of it with cell phone but they didn't come out very good. __________________ 72 chevy 3/4 ton 4X4

02-28-2009, 07:57 PM	#41
LUV2XCLR8 The LuvShack Garage Join Date: Jan 2004 Location: Maple Grove, TN (West Side) Posts: 30,470	Re: I Dunno What It Is The PO ate Mexican everyday? (Cab Vent) __________________ Owner/Op: "TN Classic Transport Carriers" The Toy: "Square Vette" 72 Hybrid Blazer Toy Barn: "LuvShack" 40 x 60 x 20 Shop Big Piggy: "Goliath" 07 Kodiak C4500 Lil Piggy:"Maddy" 88 Silverado 3500 Hauler: "Feathers" 14 Aluma 8218T

03-02-2009, 02:20 PM	#43
thirdstreettito Resident of Here Join Date: May 2008 Location: Wesley Chapel, FL, USA Posts: 7,716	Re: I Dunno What It Is __________________ ~Bradley~ 2004 Black GTO LS2/T56 too much to list Miss having a truck



Register or Log In To remove these advertisements.

03-02-2009, 02:39 PM	#44
john member #16 Join Date: Dec 1999 Location: Yuba City Ca. Posts: 3,618	Re: I Dunno What It Is And the booster. Pic from 71 c30 build. Attached Images __________________ john http://67-72chevytrucks.com/vboard/showgroups.php board vendors http://www.flickr.com/photos/1745471...7602865984234/

03-03-2009, 10:48 AM	#45
special-K Special Order Join Date: Nov 2004 Location: Mt Airy, MD Posts: 85,863	Re: I Dunno What It Is There goes my theory it was a special 1969 Woodstock Edition that came with a hippy camper built on it and this was the driver`s air supply from the back. __________________ "BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~ Last edited by special-K; 03-03-2009 at 12:25 PM.

03-03-2009, 12:06 PM	#47
LOW DOUGH I'M TRUCK CRAZY! Join Date: Oct 2006 Location: Sachse, TEXAS Posts: 1,737	Re: I Dunno What It Is it is a kanewter valve. don't know how you would spell that.

Register or Log In To remove these advertisements.