Broken Exhaust Bolt Removal - How to


I'm NEW... What now?
Mar 15, 2018
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Hey Guys

I did a lot of searching on broken exhaust bolts and decided to take the plunge to fix my manifolds on my 2004 Avalanche 5.3L. I thought my stud was long enough to grab with pliers but unfortunately I was wrong when I got in there. I tried to drill and tap my studs in the truck and the easy out just wouldn't do it so I did the weld trick. Here are my steps. Sorry, I didn't take pictures so I am just offering a step by step.

#1 - Remove crossover exhaust tube

Remove the tube using 15mm socket. I used my map gas torch with an extension tube for ease of access. Trying to manipulate the map gas canister in there is impossible. get the 4' rubber extension hose and put a bunch of heat on the nuts. It did take a breaker bar and extension tube to get two of them off. The upper one will take a wobble joint to get it.

#2 - Remove intake tube
I remove the intake tube from the air filter box for ease of access and to get stuff out of the way for easier working. Just takes a flat head screwdriver

#3 - Remove positive junction box and plug wires
This is located just below the alternator and is two 10mm bolts. Remove this and pull it out of the way. Remove the plug wires.

#4 - Move large wire loom and disconnect coolant temp sensor
This is right over the middle of the valve cover. Use a screwdriver to pry out the plastic lock and remove it. Pull it out of the way for easier access of the manifold. Disconnect the coolant temp sensor at the front of the head. Just pop if off using your finger to disconnect the lock.

#5 - Remove the manifold bolts
These are 13mm bolts. I used my map gas and again use the extension tube. Trying to get the map gas in there with the bottle is impossible. Heat the head to ensure you don't break any more bolts off in the head. Go slow.

#6 - Remove the steering intermediate shaft
If changing the manifold this will have to be done. I didn't remove the manifold so I left this in place since I wasn't changing it. You cannot pull the manifold out without doing this. You can dangle the manifold out of the way by dropping it lower down.

#7 - Cleaning the studs
I used my dremel tool with a tapered grinding stone to get all the rust off the tops of the broke studs. This is to be able to use my welder to build up material to remove the studs and grab it with vice grips

#8 - Build up weld
I used my mig welder and attached the grounding clamp to the alternator bracket. I kept spot welding until I had enough material to have plenty to grab onto

#9 - Pull the studs
Grab onto the studs with a big set of vice grips ASAP. DO NOT WAIT. This is important as the stud and head are still hot from welding and this makes it easier to come out. This takes some effort and may take repeated efforts and it was tough to do with limited space from working in the engine bay.

#10 - Assembly
I reassembled everything with new bolts and gaskets. I plan on putting on short tube headers so I used anti-seize.

This took me 4 hours total to do both sides with two broken bolts in the drivers side head (very front and very rear bolts). There is just enough room to get your mig gun in there at an angle to build up material to pull the studs. The aluminum dissipates heat very quickly and the weld doesn't bond to it so there was no major concerns of damaging the head. This was the only way to get the studs out in my situation since they were broken off in the head. I hope this helps and feel free to reach out with any questions.
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Officially Retired, B31-3 (6 G ) certified
Aug 13, 2018
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Good write up. We remove broken bolts all the time at work. I weld a build up on the broken bolt. Then weld a nut to what is sticking up. I make it so I have enough weld sticking up so I can reach the new build up weld, through the hole in the nut. The expantion that happens to the stud is what makes it loosen up. I have seen where we will heat around a bolt until its cherry red, and it wont budge. We go eat lunch, and when we come back, the bolt unscrews easy. As metal gets hot, it expands. As it cools, it shrinks, but never back to where it was before. Where the real issues come in, is aluminum.We end up doing a helicoil a lot of the time on aluminum. If I cant get a bolt out, then we mill it out on an end mill. Then ether retap to a larger size, or helicoil it. I get out about 95 percent of stuck bolts out with out milling.

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