Air Shut-Off Damper ? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**CUSTOM/10** · 11-23-2013, 03:42 PM

Does anyone have a good picture of the air shut-off damper that goes in the cowl on A/C trucks ? I'm looking for how the spring loaded pin goes into the firewall. There's a hole about 1/2" and the spring loaded pin is about 1/8. I have the plastic piece that goes on the engine bay side, but there must be something that goes on the other side, a bushing or something ?

Gary

**CUSTOM/10** · 11-23-2013, 03:53 PM

I found this picture, and it looks like there is a bushing inside the cowl where the pin goes.

Where can I get one of these ?

Gary

**CUSTOM/10** · 11-23-2013, 05:55 PM

This pic has the part I'm looking for circled

**CUSTOM/10** · 11-24-2013, 09:26 AM

Anyone ? Anyone have a picture so I could make one ?

Gary

budman k20 · 11-24-2013, 10:26 AM

I think LMC sells that part. If not try one of the many 67-72 vendors or if you're OK with a used used one try the parts board. Even another option is to make one. Pretty simple flanged bushing made from plastic. I had a hard time finding the plastic one on the firewall so I bouight a used one. Good luck!

budman k20 · 11-24-2013, 10:36 AM

I just checked LMC and they do not sell the plastic parts for the AC flapper valve.

Bigdav160 · 11-24-2013, 11:06 AM

The parts book calls number 4 a BEARING #3895487 and number 3 a CAP #3895486

That's all I got at the moment.

**CUSTOM/10** · 11-24-2013, 12:15 PM

So far I haven't been able to find one either used or after market. So I guess I'll have to make one ! I'll measure the hole and the spring pin diameters and make one from Teflon or nylon, something like that.

Gary

48richard · 11-25-2013, 12:06 PM

I ended up making one from a nylon bolt from Ace Hardware. Quick and cheap.

**CUSTOM/10** · 11-27-2013, 12:13 PM

Well I tried using a plastic fitting but it broke, so I used a brass fitting and machined the hole over sized and left a shoulder on the inside and inserted a piece of nylon tube as the bearing.

**CUSTOM/10** · 11-27-2013, 12:21 PM

One more with the damper installed.

**DaHos** · 09-25-2024, 11:35 AM

Before I too machine one does anyone know of a source for a correct oem nylon bushing?

**PbFut** · 09-25-2024, 01:21 PM

I can not fine any. I need the front one on the firewall. My back one is OK shape, but front is burnt up bad.

**GMCPaul** · 09-26-2024, 11:35 AM

Sorry to our knowledge neither nylon bushing is reproduced. Anyone with a 3D printer. Brass fitting idea was ingenious in my opinion kudos for thinking outside of the box.
Paul Jr @ GMCPauls

**PbFut** · 09-26-2024, 12:58 PM

Paul
I will have a big order for you pretty soon. Guess I'll have to make one of stock. I don't have access to 3d printer. Thanks for input.

**Rust_never_sleeps** · 09-26-2024, 03:04 PM

Might check the Hillman drawers at one of the big hw stores or McMaster Carr for a nylon "hat", seems like a common type of uncommon item

**Bob B.** · 09-27-2024, 01:27 AM

Funny there is a nice repop of the damper and the vacuum actuator but no one makes the bushings. My brother made them for me out of Delrin.

**Rust_never_sleeps** · 09-27-2024, 03:26 PM

Quote:

Originally Posted by GMCPaul

Sorry to our knowledge neither nylon bushing is reproduced. Anyone with a 3D printer. Brass fitting idea was ingenious in my opinion kudos for thinking outside of the box.
Paul Jr @ GMCPauls

IF anyone can post the dimensions, I could print some...once I upgrade my hotend to work with nylon

11-23-2013, 03:42 PM	#1
CUSTOM/10 Senior Member Join Date: May 2003 Location: Sandown, NH Posts: 2,850	Air Shut-Off Damper ? Does anyone have a good picture of the air shut-off damper that goes in the cowl on A/C trucks ? I'm looking for how the spring loaded pin goes into the firewall. There's a hole about 1/2" and the spring loaded pin is about 1/8. I have the plastic piece that goes on the engine bay side, but there must be something that goes on the other side, a bushing or something ? Gary __________________ Gary 72 SWB 4x4 My 72 SWB Build http://67-72chevytrucks.com/vboard/s...d.php?t=259859

11-23-2013, 03:53 PM	#2
CUSTOM/10 Senior Member Join Date: May 2003 Location: Sandown, NH Posts: 2,850	Re: Air Shut-Off Damper ? I found this picture, and it looks like there is a bushing inside the cowl where the pin goes. Where can I get one of these ? Gary Attached Images __________________ Gary 72 SWB 4x4 My 72 SWB Build http://67-72chevytrucks.com/vboard/s...d.php?t=259859

11-24-2013, 09:26 AM	#4
CUSTOM/10 Senior Member Join Date: May 2003 Location: Sandown, NH Posts: 2,850	Re: Air Shut-Off Damper ? Anyone ? Anyone have a picture so I could make one ? Gary __________________ Gary 72 SWB 4x4 My 72 SWB Build http://67-72chevytrucks.com/vboard/s...d.php?t=259859

11-24-2013, 10:26 AM	#5
budman k20 1972 K20 Join Date: Apr 2008 Location: Greenfield MN Posts: 360	Re: Air Shut-Off Damper ? I think LMC sells that part. If not try one of the many 67-72 vendors or if you're OK with a used used one try the parts board. Even another option is to make one. Pretty simple flanged bushing made from plastic. I had a hard time finding the plastic one on the firewall so I bouight a used one. Good luck!

11-24-2013, 10:36 AM	#6
budman k20 1972 K20 Join Date: Apr 2008 Location: Greenfield MN Posts: 360	Re: Air Shut-Off Damper ? I just checked LMC and they do not sell the plastic parts for the AC flapper valve.

11-23-2013, 05:55 PM	#3
CUSTOM/10 Senior Member Join Date: May 2003 Location: Sandown, NH Posts: 2,850	Re: Air Shut-Off Damper ? This pic has the part I'm looking for circled Attached Images __________________ Gary 72 SWB 4x4 My 72 SWB Build http://67-72chevytrucks.com/vboard/s...d.php?t=259859

11-24-2013, 11:06 AM	#7
Bigdav160 Registered User Join Date: Apr 2011 Location: Klein Texas Posts: 3,852	Re: Air Shut-Off Damper ? The parts book calls number 4 a BEARING #3895487 and number 3 a CAP #3895486 That's all I got at the moment. Attached Images __________________ My Classics: '72 K20 Suburban + '65 Dodge Town Wagon '72 Corvette Roadster +'67 Corvette Roadster '73 Z-28 Camaro '63 Ford SWB Uni Pickup '50 Ford Coupe

11-24-2013, 12:15 PM	#8
CUSTOM/10 Senior Member Join Date: May 2003 Location: Sandown, NH Posts: 2,850	Re: Air Shut-Off Damper ? So far I haven't been able to find one either used or after market. So I guess I'll have to make one ! I'll measure the hole and the spring pin diameters and make one from Teflon or nylon, something like that. Gary __________________ Gary 72 SWB 4x4 My 72 SWB Build http://67-72chevytrucks.com/vboard/s...d.php?t=259859

11-25-2013, 12:06 PM	#9
48richard Registered User Join Date: Oct 2009 Location: Phoenix, AZ Posts: 475	Re: Air Shut-Off Damper ? I ended up making one from a nylon bolt from Ace Hardware. Quick and cheap. __________________ 1971 C10 Longbed, 350/TH350

11-27-2013, 12:13 PM	#10
CUSTOM/10 Senior Member Join Date: May 2003 Location: Sandown, NH Posts: 2,850	Re: Air Shut-Off Damper ? Well I tried using a plastic fitting but it broke, so I used a brass fitting and machined the hole over sized and left a shoulder on the inside and inserted a piece of nylon tube as the bearing. Attached Images __________________ Gary 72 SWB 4x4 My 72 SWB Build http://67-72chevytrucks.com/vboard/s...d.php?t=259859

11-27-2013, 12:21 PM	#11
CUSTOM/10 Senior Member Join Date: May 2003 Location: Sandown, NH Posts: 2,850	Re: Air Shut-Off Damper ? One more with the damper installed. Attached Images __________________ Gary 72 SWB 4x4 My 72 SWB Build http://67-72chevytrucks.com/vboard/s...d.php?t=259859

09-25-2024, 11:35 AM	#12
DaHos Senior Member Join Date: Sep 2011 Location: Owosso, Michigan Posts: 2,859	Re: Air Shut-Off Damper ? Before I too machine one does anyone know of a source for a correct oem nylon bushing? __________________ 1967 C10 SWB Owner - Rustbelt Restorations

09-25-2024, 01:21 PM	#13
PbFut Senior Member Join Date: Feb 2022 Location: Ca Posts: 629	Re: Air Shut-Off Damper ? I can not fine any. I need the front one on the firewall. My back one is OK shape, but front is burnt up bad.

09-26-2024, 11:35 AM	#14
GMCPaul Senior Member Join Date: Mar 2000 Location: Rockville,In. USA Posts: 3,721	Re: Air Shut-Off Damper ? Sorry to our knowledge neither nylon bushing is reproduced. Anyone with a 3D printer. Brass fitting idea was ingenious in my opinion kudos for thinking outside of the box. Paul Jr @ GMCPauls __________________ Secure Online Catalog for-GMCPauls Truck Parts Email- GMCPAULS@GMAIL.COM

09-26-2024, 12:58 PM	#15
PbFut Senior Member Join Date: Feb 2022 Location: Ca Posts: 629	Re: Air Shut-Off Damper ? Paul I will have a big order for you pretty soon. Guess I'll have to make one of stock. I don't have access to 3d printer. Thanks for input.



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09-26-2024, 03:04 PM	#16
Rust_never_sleeps Senior Member Join Date: Jun 2022 Location: San Ramon,CA Posts: 589	Re: Air Shut-Off Damper ? Might check the Hillman drawers at one of the big hw stores or McMaster Carr for a nylon "hat", seems like a common type of uncommon item __________________ 1970 C10 Custom longbed 350/350

09-27-2024, 01:27 AM	#17
Bob B. Senior Member Join Date: Aug 2005 Location: Los Angeles Posts: 1,363	Re: Air Shut-Off Damper ? Funny there is a nice repop of the damper and the vacuum actuator but no one makes the bushings. My brother made them for me out of Delrin. __________________ 1967 GMC CM-2500 Camper Cruiser, 351E V-6, NP 435 4 speed, Dana 60, and factory A/C. 2012 GMC K-3500 WT regular cab, 6.0L Vortec, 6L90.

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