Technical Stuck exhaust manifold bolt…

Hey guys, I’m in the process of switching out my sbc mismatched cast iron exhaust manifolds for a pair of block hugger headers. All the bolts came out with my “air ratchet” except one. I started out with a 9/16 6 point socket and it rounded it off, then heated it up and tried a 14mm (slightly smaller), same thing happened, finally hammered on a 13mm socket, still no luck. The bolt is slightly inset making it difficult to grab with a big pair of vise grips. My brother suggested busting the manifold off with a cold chisel, and I do have an air hammer. I feel that the bolt is stuck in the manifold, not the head.
What say you folks? (And yes, I have sprayed liberally with penetrating lubricant!)

 

Heat….red hot

 

Weld a nut to it. You will have plenty of heat, plus a new surface for a socket.Good Luck

 

I don’t really have access with a welder, but will definitely try more heat.

 

You could cut the head off with a cut-off wheel, get the manifold out of the way, then grab the stud with vise grips, heat the stud until it glows. It'll come out. If it breaks, weld a nut on it.

 

Grind the head of the bolt off and remove the manifold. Then you have the whole long stud left to weld a nut to.

 

From my experiences, the problem is usually between the threads in the head and the threads on the bolt....not the shank of the bolt and the manifold. As suggested above, removing the bolt head will most likely allow removal of the manifold and the ability to apply heat drirectly at the juncture of the bolt and the head. You have to use an oxy/acy torch to get enough heat. A Map or Propane torch won't do it.

 

If you think the bolt is stuck in the manifold, and you have all the other bolts out, try rocking the manifold back and forth on the one bolt left. If the bolt turns with the manifold, it is stuck in the manifold. If the manifold rocks and the bolt doesn't move, the bolt is stuck in the head.

 

I had a manifold bolt stuck in the manifold, much like your thought. Usually it's stuck in the heads threads, but this one was like the bolt swelled up and was seized in the bore of the manifold. It was strange. I tried heat with the torch, cut the head off the bolt and pry on the manifold, and everything else I could think of. Finally, I just had to wiggle the manifold around enough to weaken and snap the bolt. It snapped about 1/4" proud of the head surface, so I was able to grab the remainder with pliers and it threaded right out of the head.

I had to drive the bolt out of the manifold with an air hammer, from the outside in. No amount of heat or BFH would do the trick. The bolt had the same stamping on the head as the rest of them, so it wasn't an oddball.

 

You didn't specify which penetrant you used, (hopefully something more than wd40). I would cut the bolthead off, remove the manifold and spray Kroil where the bolt goes into the head. Apply heat, It will come out.

 

I had an issue removing the transmission drain plug on my ‘03 PU. 6 pt socket rounded the head. Hammers a metric 6 point on it, rounded it some more.
I recall something I saw at AutoZone, went and bought a set of impact style sockets made to grip/stab into any part of the flats that are left.
The “teeth” are kinda pointed and angled so that they dig in when turned CCW.
I was hesitant to heat the plug red while submersed in transmission fluid.
These worked very well. If I spot them on my way to work I’ll snap a pic for a better explanation

 

I only use Gibb’s penetrating oil. I have probably been using it for 5 decades.
I will have to go to my Autozone and check out those sockets. The bolt head actually doesn’t look that bad…

 

These are similar to what I bought.


https://www.autozone.com/test-scan-...lt-extractor-set-with-storage-case/486979_0_0


Mine are a deep “socket” though. Also, I recall I had to return the first set, it had 5 or 6 pieces, but skipped over 9/16ths or 1/2 in. The set I wound up with had a few more.
So pay attention to what’s on the label.

 

The blue wrench is the best bet. Someone turned me onto mapp gas years ago, it works better than propane and not as good as oxy-acetylene. I would go with 3 or 4 heat and cool cycles.

 

Were you able to find them and try them out?

Edit: I meant to add, I’ve never had luck (gave up decades ago) using a PB, etc on bolts. Nuts, or bolts I could get access to the threads, yes. But never had good luck trying to seep the penetrating fluid under a bolt head.

 

I am heading out today to buy a set, and will also get a “map gas” torch…

 

Q: does the “Map” gas cylinder use the same torch tip as my propane torch? I don’t want to buy a new one if I don’t need to…

 

Yes! The map gas comes in a yellow bottle..

 

Tips are different. Get a map gas torch. They should have an igniter built in. Some have a hose which is better for tight areas

 

Roger that, thanks…

 

Hate to be a pessimist, but I foresee that head being removed in the not too terribly distant future.

 

I have some of those as well as some ratcheting box end wrenches equipped the same way. Don't use all the time, but have worked out.

 

Had a 283 once with multiple stuck manifold bolts. Wound up cutting the head off of 4 or 5 of them to remove the manifolds. I don't know if it was the heat of cutting them off or the vibration but all spun out of the heads relatively easy afterwards. Good luck.

 

Try an air hammer on it, hit the bolt dead center to try bust the rust loose, then hit it from three sides to move it sideways. Then spray lube and heat for good measure.

 

Picked up a map gas torch set and a set of “extractor” sockets.
Won’t be able to try them until tomorrow.
I will keep you all updated…

 

I would cut the head off the bolt, then remove manifold. Soak the remainder of the bolt with penetrating oil. Use a pipe wrench to remove bolt. The pipe wrench wedges it's jaws when you start turning it.

 

I think this is the best advice given here yet. Ultimately the bolt is bound in the threads of the heads. Heating the bolt all the way out at the end may not get you the desired result, and may only make matters worse since if the threads are truly bound, and you really get a good grip on what's left of the head, the torquing of the bolt may snap the bolt off in the head. Then you've got a real issue. Getting the manifold off will allow you to get heat closer to the threads, and allow you to get a wrench closer to where it's stuck.

 

As mentioned earlier HEAT is your friend. Heat up red hot , quench with cold water , do that process several times. Weld a rod coupler nut onto the bolt. Unscrew the stuck bolt even if the bolt is stuck in the manifold. You will be surprised how easy that bolt will come out.
Vic

 

If you dont have Kroil Try ATF mixed with acetone let sit for a few hours, wipe excess up and apply lots of heat.
Let cool and repeat a few times, then heat up and give it a go. You might get lucky.

 

Temperature differential is what works..... I wonder if holding dry ice on the head of the bolt to shrink it, let it normalize to ambient temperature, more dry ice, normalize, hit it with heat, repeat.
Pain in the *** to do, but the metal doesn't know if it's hot or cold, only that it's going through a heat (differential) cycle.