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[GMCnet] One thing leeds to another. [message #334466] Mon, 02 July 2018 21:29 Go to next message
BobDunahugh is currently offline  BobDunahugh   United States
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Registered: October 2010
Location: Cedar Rapids, IA
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I brought up the heatshields. That got me looking more closely at the exhaust system. Pipes are fairly good. BUT. Who ever replaced the system. They didn't put the 3" sleeves in the muffler bearings. ( And for those new owners. Our GMC's really do have muffler bearings. Really. ) So now I'm replacing the exhaust system. I've always seen the bearing sleeve welded to the tail pipe. Is that what GM did? Someone told me that GM used self drilling screws. I don't think that's the case. Bob Dunahugh
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Re: [GMCnet] One thing leeds to another. [message #334468 is a reply to message #334466] Mon, 02 July 2018 22:02 Go to previous messageGo to next message
powwerjon is currently offline  powwerjon   United States
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Registered: March 2013
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Bob,
The muffler bearings are for a 3” pipe. The 2.5 in had a 3” sleeve welded to the pipe.

http://www.appliedgmc.com/prod.itml/icOid/1180


http://www.gmcmhphotos.com/photos/general-pictures/p64945-3-26quot-3b-sleve.html
http://www.gmcmhphotos.com/photos/general-pictures/p64946-3-26quot-3b-sleve.html
http://www.gmcmhphotos.com/photos/general-pictures/p64945-3-26quot-3b-sleve.html

J.R. Wright
GMC Great Laker MHC
GMCGL Tech Editor
GMC Eastern States Charter Member
GMCMI
78 GMC Buskirk 30’ Stretch
75 GMC Avion (Under Reconstruction)
Michigan


> On Jul 2, 2018, at 10:29 PM, Bob Dunahugh wrote:
>
> I brought up the heatshields. That got me looking more closely at the exhaust system. Pipes are fairly good. BUT. Who ever replaced the system. They didn't put the 3" sleeves in the muffler bearings. ( And for those new owners. Our GMC's really do have muffler bearings. Really. ) So now I'm replacing the exhaust system. I've always seen the bearing sleeve welded to the tail pipe. Is that what GM did? Someone told me that GM used self drilling screws. I don't think that's the case. Bob Dunahugh
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Re: [GMCnet] One thing leeds to another. [message #334490 is a reply to message #334466] Tue, 03 July 2018 10:31 Go to previous messageGo to next message
Matt Colie is currently offline  Matt Colie   United States
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Registered: March 2007
Location: S.E. Michigan
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Bob,

There is no way I would use self drilling screws there and I am sure that GM would not have done so either. It would be warranty in waiting.

Mine had been replaced and the installer just hammered the 3" down close enough to make an easy weld to the 2-1/2.

I cut the 3" to have four long ears on each end and used a muffler U-bold to make them up to the 2-1/2. It has only been a year so I cannot say how good a fix this was.

Matt


Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
Re: [GMCnet] One thing leeds to another. [message #334509 is a reply to message #334466] Tue, 03 July 2018 13:32 Go to previous message
jhbridges is currently offline  jhbridges   United States
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Registered: May 2011
Location: Braselton ga
Karma: -74
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When I had the local guy do the ratrod exhaust, he took a piece of 2 1/2" pipe and expanded one end on his Muffler Person' machine till the 3' was a snug fit, and then MIG welded all the joints. Doesn't leak and doesn't rattle.

-johnny


Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons. Braselton, Ga. I forgive them all, save those who hurt the dogs. They must answer to me in hell
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