Exhaust Manifold Replacement

[rennalds]

My son has a 71 Cheyenne with a 350 and we are gettin ready to replace the Drivers side exhaust manifold. We have been hitting the bolts with penetrating oil all week. Problem is that one of the bolts appears to already be loose. It turns freely and wiggles but it doesnt come all the way out. Hoping this isn't a broken bolt? Also I know from other posts that the bolts are 3/8 & 16 but does anyone know how long the originals are?? If the bolts is broken and we have to drill and tap it anyone know what the right size drill bit is to accomplish this? How dow we know how far to drill in with out going to far??? Thanks in advance for your help!!!!!

[rsavage]

The rusty bolts grow a "waistline" of rust which prevents them from pulling out easily when loose. If it is turning freely, it is probably broken off. I pull the head off to drill out and retap. I don't know how you could do it easily with the engine in the truck. Maybe by dropping the inner fender out of the way. Because I had the head on a bench, I was able to center the pilot drill carefully, insure that I was drilling straight, and used successively larger drills until I was almost to the threads. Got the shell of the bolt out and then cleaned things up with a bottom tap.

[Todersauce]

A good set of left handed Drill bits is a gerat thing to use on any broken bolt. Instead of screwing the bolt in it tends to grab with some good pressure and unscrew the bolt. Heat and cold work wonders also. I had the same problem on my drivers side manifold. I had enough to get a vice grip on it. I bolted the manifold on it and ran it untill it got hot took off my manifold and gave it alot of pen oil then used ice to cool the stud and went after it with the vice grips. It didnt fall out but it did come out after a few cycles.

[WIDESIDE72]

Originally Posted by Todersauce

A good set of left handed Drill bits is a gerat thing to use on any broken bolt. Instead of screwing the bolt in it tends to grab with some good pressure and unscrew the bolt. Heat and cold work wonders also.

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[hayhauler71]

When i have a broken bolt to get out i weld a nut to it and then remove it.

[SSedan64]

I recently replaced the Manifolds on my 71-C10, man what a head ache. Many bolts broke, fortunately they usually break about mid way because they're so rusted. I finally knocked a hole in the top of one Manifold and took a long prybar to it. Came of in about 6 pieces. Then I just used Vise grips to turn what was left of most bolts. One I did weld a nut on one that was very tight. Used a Cutoff wheel on a few because of the bolt heads being so mangled.

My Manifolds were cracked so bad they looked like they had Lepracy.

[ebry710]

Originally Posted by SSedan64

My Manifolds were cracked so bad they looked like they had Lepracy.

My manifold is cracked so bad that I though there was a spider web in front of it.

I like the though of removing it in pieces, since it already is. Good idea.

I just have to make sure pieces don't end up in my exhaust port.

[tim21391]

Originally Posted by WIDESIDE72

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