Vacuum gauge question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

68 50th · 07-30-2005, 11:53 AM

I just got a tach vac conversion kit but the vac gauge needle is in, from what I understand in the wrong position. (See pic)
Can I just pull the needle off and put it back in the 0 position or is there another way to calibrate the vac gauge?
I bought it from a friend who had a guy in the US byuing two sets for him, one for him and one for me but I don't know from which parts store this came, the instruction says Counterpart Automotive, everything is brand new.
Any input would be greatly appreciated.

Thanks

matthufham · 07-30-2005, 12:33 PM

you cant move the needle without taking it off? no matter where it's at when you first turn the key it should calibrate itself.

68 50th · 07-30-2005, 01:27 PM

Thanks matthufham,
The needle is possible to move but once I let it loose it goes back to the position in the pic.
I thought it would be at 0 when no vacuum is connected to it, if I connect it to vacuum the needle is moving even further pass the 30 line.

BobS · 07-30-2005, 01:55 PM

Is there a way to turn the vacuum chamber on the back side? I've got one of the originals but I can't remember what the back side looks like.

Bob

68 50th · 07-30-2005, 02:54 PM

I don't think it's possible to turn the vacuum chamber but your thought made me look closer at the back side.
I found that the part that is marked on pic maybe would be possilble to bend a little, I believe that would adjust the needle but I'm not sure that is the way to do it.

OhioDan · 07-30-2005, 03:39 PM

68 50th, that is where you would bend to calibrate the gauge. However, without anything to compare it to, you wouldn't know if you were right or wrong. The easiest way, is just to remove the pointer, and re-zero it. Useta calibrate gauges in the service. Hope this helps?

TN70C10 · 07-30-2005, 03:49 PM

check it with a vacuum gauge/pump after you reset the needle. you can get them at sears for cheap. it has a gauge and you can apply vacuum with it to check your calibration.

68 50th · 07-30-2005, 04:58 PM

Thank you all for your replies, it helps a lot.
I will get something to compare it to.

Thanks

CG · 07-30-2005, 04:59 PM

dont get the austin powers vacuum gauge/pump, people might wonder

355 · 07-30-2005, 06:01 PM

The tube on the back is a bordon (spelling may be wrong, but thats how you say it). I would not do anything to bend it. It works on expansion/contraction. You can go to a local Aircondition shop and they will have a vacuum pump that you could tee your guage in with theirs and calibrate it.

68 50th · 07-30-2005, 06:13 PM

Quote:

Originally Posted by CG

dont get the austin powers vacuum gauge/pump, people might wonder

I'll better try something else, even though I saw it was named The Swedish Xxxxx Pump.

68 50th · 07-30-2005, 06:21 PM

Quote:

Originally Posted by 355

The tube on the back is a bordon (spelling may be wrong, but thats how you say it). I would not do anything to bend it. It works on expansion/contraction. You can go to a local Aircondition shop and they will have a vacuum pump that you could tee your guage in with theirs and calibrate it.

I wouldn't bend the tube itself but the marked area in the pic looks like it could work as an adjustable link.

with the AC shop, I'll try that.
Thanks

07-30-2005, 11:53 AM	#1
68 50th Senior Member Join Date: Jul 2004 Location: Sweden Posts: 833	Vacuum gauge question I just got a tach vac conversion kit but the vac gauge needle is in, from what I understand in the wrong position. (See pic) Can I just pull the needle off and put it back in the 0 position or is there another way to calibrate the vac gauge? I bought it from a friend who had a guy in the US byuing two sets for him, one for him and one for me but I don't know from which parts store this came, the instruction says Counterpart Automotive, everything is brand new. Any input would be greatly appreciated. Thanks Attached Images __________________ Mats.. ---------------------------------------------------- 1971 Cheyenne Super Custom Camper 475CBB/TH400/AC 1992 Silverado Sport Truck 1988 Silverado 2500 Ext Longbed 4x4 2001 GMC Sierra SLT 4x4 1990 Chevrolet K3500 1965 Pontiac Grand Prix 1980 Z 28 350/4-speed/AC/T-top 1980 Camaro Coupe V6/3-speed 1979 Buick Century Wagon

07-30-2005, 12:33 PM	#2
matthufham Registered User Join Date: Feb 2005 Location: Carl Junction, Missouri Posts: 2,061	you cant move the needle without taking it off? no matter where it's at when you first turn the key it should calibrate itself. Last edited by matthufham; 07-30-2005 at 12:33 PM.

07-30-2005, 01:27 PM	#3
68 50th Senior Member Join Date: Jul 2004 Location: Sweden Posts: 833	Thanks matthufham, The needle is possible to move but once I let it loose it goes back to the position in the pic. I thought it would be at 0 when no vacuum is connected to it, if I connect it to vacuum the needle is moving even further pass the 30 line. __________________ Mats.. ---------------------------------------------------- 1971 Cheyenne Super Custom Camper 475CBB/TH400/AC 1992 Silverado Sport Truck 1988 Silverado 2500 Ext Longbed 4x4 2001 GMC Sierra SLT 4x4 1990 Chevrolet K3500 1965 Pontiac Grand Prix 1980 Z 28 350/4-speed/AC/T-top 1980 Camaro Coupe V6/3-speed 1979 Buick Century Wagon Last edited by 68 50th; 07-30-2005 at 01:28 PM.

07-30-2005, 01:55 PM	#4
BobS Senior Member Join Date: May 2001 Location: West Central Minnesota Posts: 568	Is there a way to turn the vacuum chamber on the back side? I've got one of the originals but I can't remember what the back side looks like. Bob __________________ V-6....only GMC Trucks have it! 62 GMC W5000 NAPCO-V6 65 GMC 2500 NAPCO Panel-V6 66 GMC 1000-V6 66 GMC 1500-V6 67 GMC K1500-SBC (originally a KM-V6) 68 GMC C1500-V6 68 GMC C1500-V6 68 GMC Suburban C2500 70 Chevy K20-SBC 71 Chevy C30 Longhorn-SBC 72 GMC Suburban C1500-BBC 72 Chevy C10-SBC 72 GMC C5500-ToroFlow Diesel

07-30-2005, 02:54 PM	#5
68 50th Senior Member Join Date: Jul 2004 Location: Sweden Posts: 833	I don't think it's possible to turn the vacuum chamber but your thought made me look closer at the back side. I found that the part that is marked on pic maybe would be possilble to bend a little, I believe that would adjust the needle but I'm not sure that is the way to do it. Attached Images __________________ Mats.. ---------------------------------------------------- 1971 Cheyenne Super Custom Camper 475CBB/TH400/AC 1992 Silverado Sport Truck 1988 Silverado 2500 Ext Longbed 4x4 2001 GMC Sierra SLT 4x4 1990 Chevrolet K3500 1965 Pontiac Grand Prix 1980 Z 28 350/4-speed/AC/T-top 1980 Camaro Coupe V6/3-speed 1979 Buick Century Wagon

07-30-2005, 03:39 PM	#6
OhioDan Registered User Join Date: Apr 2002 Location: New Carlisle, Ohio,USA Posts: 1,404	68 50th, that is where you would bend to calibrate the gauge. However, without anything to compare it to, you wouldn't know if you were right or wrong. The easiest way, is just to remove the pointer, and re-zero it. Useta calibrate gauges in the service. Hope this helps? __________________ LIFE AIN'T EASY WHEN YER FAT AND GREASY! GMC= Got More Class! 1970 GMC LWB, Fleetside, 350/4spd, Flowmaster "40's", 2002 GMC 16" Rallies, cowl hood,and added a bunch of options that weren't there when I started.

07-30-2005, 03:49 PM	#7
TN70C10 Registered User Join Date: Jun 2005 Location: Chattanooga TN Posts: 115	check it with a vacuum gauge/pump after you reset the needle. you can get them at sears for cheap. it has a gauge and you can apply vacuum with it to check your calibration.

07-30-2005, 04:58 PM	#8
68 50th Senior Member Join Date: Jul 2004 Location: Sweden Posts: 833	Thank you all for your replies, it helps a lot. I will get something to compare it to. Thanks __________________ Mats.. ---------------------------------------------------- 1971 Cheyenne Super Custom Camper 475CBB/TH400/AC 1992 Silverado Sport Truck 1988 Silverado 2500 Ext Longbed 4x4 2001 GMC Sierra SLT 4x4 1990 Chevrolet K3500 1965 Pontiac Grand Prix 1980 Z 28 350/4-speed/AC/T-top 1980 Camaro Coupe V6/3-speed 1979 Buick Century Wagon

07-30-2005, 04:59 PM	#9
CG BlahBlahBlah Join Date: Feb 2002 Location: Wa. Posts: 20,046	dont get the austin powers vacuum gauge/pump, people might wonder

07-30-2005, 06:01 PM	#10
355 Registered User Join Date: May 2005 Location: South Mississippi Posts: 81	The tube on the back is a bordon (spelling may be wrong, but thats how you say it). I would not do anything to bend it. It works on expansion/contraction. You can go to a local Aircondition shop and they will have a vacuum pump that you could tee your guage in with theirs and calibrate it. __________________ 1969 C10 Long Step,355,700r4w/lockup, HEI,Weiand,750 Performer,1.6 rockers,Camel Humps,Comp 262Extreme,Hedman,2 1/2"pipes, tele/tilt,SunRoof,ps,Disc pb,ac,Cragar,eaton,Corvette style roll pan, Bowtie louvered tail gate,lowered 2/2.

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