Help!! Exhaust manifold leaks - The 1947 - Present Chevrolet & GMC Truck Message Board Network

mhicks · 04-15-2004, 02:19 PM

I got a '73 from my dad and he bought it new. He has apparently replaced the driver's side exhaust manifold with a newer one. It looks like it had 4 tubes coming out of it and I assumed they went to a sensor of some kind. Well, the tubes have been bent over and they worked fine for a while. Now the tubes have rusted out and pitted and they leak. I tried unscrewing the flange nut that goes around it but it broke off. Does anybody know how I can plug those holes so they won't leak. I really don't want to replace the manifold.

PHOENIX · 04-15-2004, 02:29 PM

Those lines you are talking about are for the AIR (smog) system. Some trucks have a pump that pumps air into the manifolds for emissions.
cut the tubes as close as you can to the nut (about 1/2" or so). An air saw with a fine tooth blade works great. Then put a socket on it and back them off. Go down to Lowes/Homedepot and buy some plugs. I believe they are 1/4" brass plugs. Looking in the plumbing section (not hardware). The shaft of the plug is actually 1/2", but you will see the are 1/4" brass plumbing plugs. Use a metric 12-pt socket on the square head of the plugs, it works great.

mhicks · 04-15-2004, 02:31 PM

I tried backing one of them out and it broke off.

PHOENIX · 04-15-2004, 02:36 PM

You need to be carefull then. Because the tube is crimped on the inside of that nut and thats what holds the tube in place. If you cut the tube and push it into the nut it will fall inside (you dont want that). I am not sure what you are going to do about the broken one. But the post above should help with the rest of them. Getting a socket around the nut will help spread the stress and make it less likely to break.

PHOENIX · 04-15-2004, 02:40 PM

How exactly did the nut break, any pictures?
Pictures may help with ideas on how to get it out.

mhicks · 04-15-2004, 02:42 PM

I was wondering if I could just maybe grind the tubes off flush and put some JB Weld in it or something?

PHOENIX · 04-15-2004, 02:51 PM

Once the tubes are cut they are loose.
They will fall inside the manifold.
To do it right, you need to get the tubes and nuts out then install a plug.

04-15-2004, 02:19 PM	#1
mhicks Registered User Join Date: Jan 2004 Location: Weatherford,Tx Posts: 747	Help!! Exhaust manifold leaks I got a '73 from my dad and he bought it new. He has apparently replaced the driver's side exhaust manifold with a newer one. It looks like it had 4 tubes coming out of it and I assumed they went to a sensor of some kind. Well, the tubes have been bent over and they worked fine for a while. Now the tubes have rusted out and pitted and they leak. I tried unscrewing the flange nut that goes around it but it broke off. Does anybody know how I can plug those holes so they won't leak. I really don't want to replace the manifold.

04-15-2004, 02:29 PM	#2
PHOENIX Registered User Join Date: Oct 2002 Location: Phoenix, Arizona Posts: 4,703	Those lines you are talking about are for the AIR (smog) system. Some trucks have a pump that pumps air into the manifolds for emissions. cut the tubes as close as you can to the nut (about 1/2" or so). An air saw with a fine tooth blade works great. Then put a socket on it and back them off. Go down to Lowes/Homedepot and buy some plugs. I believe they are 1/4" brass plugs. Looking in the plumbing section (not hardware). The shaft of the plug is actually 1/2", but you will see the are 1/4" brass plumbing plugs. Use a metric 12-pt socket on the square head of the plugs, it works great. __________________ * AVOID: LOPER'S PERMORANCE / LOPERSPEED.COM OF PHOENIX, AZ & COTTMAN TRANSMISSION *

04-15-2004, 02:31 PM	#3
mhicks Registered User Join Date: Jan 2004 Location: Weatherford,Tx Posts: 747	Exhaust I tried backing one of them out and it broke off.

04-15-2004, 02:36 PM	#4
PHOENIX Registered User Join Date: Oct 2002 Location: Phoenix, Arizona Posts: 4,703	You need to be carefull then. Because the tube is crimped on the inside of that nut and thats what holds the tube in place. If you cut the tube and push it into the nut it will fall inside (you dont want that). I am not sure what you are going to do about the broken one. But the post above should help with the rest of them. Getting a socket around the nut will help spread the stress and make it less likely to break. __________________ * AVOID: LOPER'S PERMORANCE / LOPERSPEED.COM OF PHOENIX, AZ & COTTMAN TRANSMISSION * Last edited by PHOENIX; 04-15-2004 at 02:38 PM.

04-15-2004, 02:40 PM	#5
PHOENIX Registered User Join Date: Oct 2002 Location: Phoenix, Arizona Posts: 4,703	How exactly did the nut break, any pictures? Pictures may help with ideas on how to get it out. __________________ * AVOID: LOPER'S PERMORANCE / LOPERSPEED.COM OF PHOENIX, AZ & COTTMAN TRANSMISSION *

04-15-2004, 02:42 PM	#6
mhicks Registered User Join Date: Jan 2004 Location: Weatherford,Tx Posts: 747	I was wondering if I could just maybe grind the tubes off flush and put some JB Weld in it or something?

04-15-2004, 02:51 PM	#7
PHOENIX Registered User Join Date: Oct 2002 Location: Phoenix, Arizona Posts: 4,703	Once the tubes are cut they are loose. They will fall inside the manifold. To do it right, you need to get the tubes and nuts out then install a plug. __________________ * AVOID: LOPER'S PERMORANCE / LOPERSPEED.COM OF PHOENIX, AZ & COTTMAN TRANSMISSION *

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