Exhaust manifold bolt ... advice needed!

[johnmark]

I recently purchased a 1997 Ford Class A with a 460 engine. The exhaust manifold issues have been well documented and so I decided to put Banks headers and exhaust on it. All my manifold bolts seemed intact and so I started. The first one came out fairly easy but the infamous rear passenger bolt broke off. Only the head of the bolt broke so it is now flush with the manifold. Reading the horror stories of seized bolts and extraction nightmares and an upcoming trip in 3 weeks, I am thinking of just replacing my exhaust system but not the manifold at this point (which should lower the manifold temps). Since the bolt is flush and accessible I am wondering if it is possible to just weld a washer and nut on there and take it on my 3,000 mile trip. I have not had any leaks and the manifold looks good. I have attached a photo and would like to get some input on whether this is doable.



Another option I thought of was to just weld the hole shut since I will be replacing the manifold with headers after I get back from my trip anyway.

Any thoughts would be greatly appreciated! Thanks!

[KCFDCapt]

The manifold will have to come off to give access to slip the nut over the remaining bolt.

[Raymon]

Excuse me, but the OP stated "Only the head of the bolt broke so it is now flush with the manifold". Also, in the picture, it looks like the flange of the manifold is not tight up against the engine. If the OP decides to do nothing, the manifold will leak. If he has 3 weeks to repair, I would definitely try to get the bolt out now. It has to come out sometime.

Ray

[kaz442]

I would weld a nut on before your trip. As the .manifold heats up it expands and the nut will hold it in place. You do not want it to become an exhaust leak that is right next to your spark plug wire.
I had two broken bolts on mine, one was like yours that I welded a nut to and other was flush with the head. For that one I drilled and tapped it and put a stud and a nut.
I do have a slight exhaust leak but it quiets done as the manifold heats up.
JKaz

[johnmark]

@KCFDCapt
So you think I can do this without having to remove the remaining bolts and have remove the manifold?

[KCFDCapt]

If you know someone who has a TIG welder, or have one yourself, here is the method I have used on the Ford 460 to remove that stud. Begin by heating the stud to red hot with the tungsten and allow the heat to sink in. Repeat a couple of more times. You are also annealing the bolt so it is not so apt to snap off. Then take a nut that will slip over the remaining headless bolt. TIG weld the nut to the bolt. Allow the weld job to cool and use the proper size wrench to screw the broken stud out of the head.

[the_armadillo]

Had a similar broken bolt on my 5.4 Triton F150. Spray around the broken shaft with a good penetrating lubricant and drive it thru a number of heat cool cycles. Respray and do it again. I personally use Aerokroil. When I removed the manifold, I was able to remove quite easily with vice-grips. Tapping (good hard tap) on the other bolts prior to removal as suggested is a very good idea too. Good luck. My truck no longer clatters on cold start after repair.

[usn2beagles]

I have used left handed drill bits to take out broken studs/bolts it works surprisingly well. Easiest is to remove the manifold and use a stud remover or vise grips etc, if you cant get it off over the stud try a center punch and a 5/16th Left hand bit.. Good luck with it!

[RLS7201]

indyzmike wrote:
Leave drill in the toolbox. There is no need to drill since so much of the stud is sticking out. You can put the rest of the bolts back in until your trip is over, or take the manifold off to expose the stud. Once the manifold is off, do like others have said, use penetrating oil, like Liquid Wrench or Aerokroil to soak in around the threads. WD-40 sucks at loosening bolts. Do this for a couple days by spraying a couple times a day. You can weld a nut on the stud to turn it, or use a small pipe wrench to grip on the stud. If you weld a nut onto the stud, weld it about a quarter inch from the engine and use a box end wrench to turn it. This allows more rotational force and less side, or radial force to snap the stud off. While carefully applying pressure to turn the bolt, tap on the end of it with a hammer, like pounding in a nail. The penetrating oil and the shock of the hammer should make it back out. Do not force the stud to turn, the stud sticking out is a luxury. Don't break it off. If it breaks off, THEN you go to the toolbox and get out that drill.

Good advice. One other trick is to tap on the end of the stud, after you remove the manifold. That will help shake the stud loose from the rust.

Richard

[ScottG]

There are two more ways to get it out after the manifold is removed.

Heat them up cherry red and touch the base with a wax candle. Then try to rock the bolt back and forth. The wax will wick into the threads and lubricate them and the bolt will "pop" free. (I actually watched this once - amazing!)

The next way is to simply use a cutting torch to BLOW the remnants of the bolt out of the hole. You'd think this would damage the threads but they're so heat-sinked that it doesn't harm them.

I've seen my mechanic buddy (not a "technician" but a true mechanic) perform both of these feats and he has never failed to get one out.

[johnmark]

I am just amazed at all the great responses and how quickly you came through. Thanks a million!

Just to clarify, the first bolt came out fairly easy. Two others I tried but didn't get anywhere so I didn't force it and left them. I then did the rear bolt in the picture and it broke right off. With my upcoming trip and it not leaking I just felt like this was not the time to go on as I had the feeling other bolts would have broken.

I think I will just put the one bolt back in and have someone weld a nut on it and take my trip. After I get back I can then try to use that welded nut to back out the stud. If it won't go, I can always cut the nut off and work on the stud once the manifold is removed.

Here is another thought I had and would love to get input if this is a good idea or anyone ever used this approach. I am thinking, the bolts that feel like they will break, instead of breaking them, why not just grind off the top of the bolt and pull the manifold with stud still in. That way I am guaranteed to have enough stud to work with and don't risk breaking it flush with the head. With manifold off, I can then soak the threads, apply heat, use a vise grip or two nuts (or weld one on) 1/4" away from the head and back it out. The only question is, if I have enough clearance with the studs still in to pull the manifold? Any thoughts?

[K_Charles]

The trip is the most important thing. Put the other bolt back in and don't worry about it. When you get home as others have said, you can get that bolt out after you remove the manifold.

[eHoefler]

A good welder will weld a nut to the stud and let it cool, once cool, it will back out quite easily. I have done it many times using my MIG.

[RayChez]

indyzmike is correct that the drill should be the last option. Breaking cap screws was an everyday occurrence in the railroad removing the air valves. So I know that even if broken flush welding a nut on top of the broken screw was the best way. Drilling you got to have lots of room around the area you are going to drill. Then you have to get a center punch to make a tiny indentation on the center of the broken screw so as to keep it centered or else there is the danger of drilling to the side and messing up the threads.

But if you do not know how to weld (forget it) go to a professional to do the job.

[PaulJ2]

indyzmike wrote:
Leave drill in the toolbox. There is no need to drill since so much of the stud is sticking out. You can put the rest of the bolts back in until your trip is over, or take the manifold off to expose the stud. Once the manifold is off, do like others have said, use penetrating oil, like Liquid Wrench or Aerokroil to soak in around the threads. WD-40 sucks at loosening bolts. Do this for a couple days by spraying a couple times a day. You can weld a nut on the stud to turn it, or use a small pipe wrench to grip on the stud. If you weld a nut onto the stud, weld it about a quarter inch from the engine and use a box end wrench to turn it. This allows more rotational force and less side, or radial force to snap the stud off. While carefully applying pressure to turn the bolt, tap on the end of it with a hammer, like pounding in a nail. The penetrating oil and the shock of the hammer should make it back out. Do not force the stud to turn, the stud sticking out is a luxury. Don't break it off. If it breaks off, THEN you go to the toolbox and get out that drill.

I agree with above. Take your trip then remove the manifold when you get back home. Does not seem to be leaking around the broken bolt so don't weld anything on it. Like above, remove the manifold, soak the threads with a solvent many times, grab it with a vise grips and work it loose.
I have found that ordinary carb cleaner spray (like gumout)works the best for loosening rusted bolts. Is thin,gets into the threads,works better than anything else.

[PaulJ2]

indyzmike wrote:
Leave drill in the toolbox. There is no need to drill since so much of the stud is sticking out. You can put the rest of the bolts back in until your trip is over, or take the manifold off to expose the stud. Once the manifold is off, do like others have said, use penetrating oil, like Liquid Wrench or Aerokroil to soak in around the threads. WD-40 sucks at loosening bolts. Do this for a couple days by spraying a couple times a day. You can weld a nut on the stud to turn it, or use a small pipe wrench to grip on the stud. If you weld a nut onto the stud, weld it about a quarter inch from the engine and use a box end wrench to turn it. This allows more rotational force and less side, or radial force to snap the stud off. While carefully applying pressure to turn the bolt, tap on the end of it with a hammer, like pounding in a nail. The penetrating oil and the shock of the hammer should make it back out. Do not force the stud to turn, the stud sticking out is a luxury. Don't break it off. If it breaks off, THEN you go to the toolbox and get out that drill.

I agree with above. Take your trip then remove the manifold when you get back home. Does not seem to be leaking around the broken bolt so don't weld anything on it. Like above, remove the manifold, soak the threads with a solvent many times, grab it with a vise grips and work it loose.
I have found that ordinary carb cleaner spray (like gumout)works the best for loosening rusted bolts. Is thin,gets into the threads,works better than anything else.