[Z69GP]

The job of converting from stock to Long Branch manifolds on my '69 Grand Prix has begun. I have 8 bolts to deal with, and they are 9/16". I removed 3 of the 8 bolts no problem, but the others seems smaller than 9/16"....but not as small as 1/2". These bolts are all original and seem to have suffered degradation over the years. I have tried to fit a 13mm wrench on the bolts but cannot loosen them. I am also trying to avoid stripping the heads.

Any suggestions?? I am hoping to complete this task w/o having to pull the engine.

[Dick Boneske]

You may be able to hammer a 1/2" socket or box wrench onto the bolt heads. I've had success doing that.

It's common for the exhaust manifold bolt heads to deteriorate like that.

[Schurkey]

They are not 9/16 bolts. They are 3/8 bolts with 9/16 heads.

The small ones have lost material due to corrosion. Damaging the heads is the least of your concern.

Get a torch. A real torch. Oxy-Acetelyne is your friend.

[67gtospud]

Heating them up and pounding a socket on tight is probably your best way to go about this

[Doug]

Originally Posted by Z69GP

The job of converting from stock to Long Branch manifolds on my '69 Grand Prix has begun. I have 8 bolts to deal with, and they are 9/16". I removed 3 of the 8 bolts no problem, but the others seems smaller than 9/16"....but not as small as 1/2". These bolts are all original and seem to have suffered degradation over the years. I have tried to fit a 13mm wrench on the bolts but cannot loosen them. I am also trying to avoid stripping the heads.

Any suggestions?? I am hoping to complete this task w/o having to pull the engine.

Since the engine is installed you probably don't have much maneuvering room, even for hammering. One thing you may want to try is cutting/grinding the heads of the bolts off with a Dremel or cutoff tool and sliding the manifold out? off? Even if you don't clear the bolts you can cut them off as needed leaving enough of the stems to work with using use vice grips or pipe wrench to turn the bolt studs (after heating them or applying penetrating oil doses). EASY does it!

When you install the longbranch, make sure there are enough hole-threads so the bolts can be fully torqued. (The holes are not threaded all the way to the bottom.) Also, you should use the "thick" solid washers that are used on some Pontiac manifolds.

Good luck!

[Sirrotica]

If you need more room to work, remove the motor mount bolts and jack the engine up on the side your working on. You'd be surprised how much room you'll gain to work if you do that.

One other suggestion is you really need to get the cast iron around the bolts hot (cherry red) and an oxy acetylene torch is the only way to get enough heat to get the bolts to release, as has already been said. If you don't have access to one take the car to a muffler shop and pay them to do the removal. Muffler shops deal with rusted manifold bolts every day and will be able to remove the old bolts without breaking them off in the head. These old bolts crystallize through the many hot and cold cycles and are brittle and break fairly easily. also as you've already found out they corrode from rust and may be much smaller diameter inside the manifold where you can't see, lending themselves to break more easily than a full sized non rusted bolt.

Being a mechanic for 45 years and specializing in Pontiacs, I know how much a pain in the butt it is to remove broken bolts that someone else broke off trying to do the job at home to save some money. In this case you'll be money ahead to pay someone with the background and correct equipment to remove the bolts rather than paying someone to remove bolts you break off. Not many people want to try to remove broken bolts in a Pontiac head without removing the head from the engine. It can be done in car but, it's a real ordeal.

[428GTO70]

try a 14mm? 6 point of course also, no 12 point sockets/wrenches. and yes heat.

[Grand73Am]

For deteriorated or rounded off bolt heads and nuts, these Irwin "Bolt grips" work great. The sharp, fluted design of the socket gets a good grip on the bolt head and use a 3/8" ratchet with them. I bought mine at Northern Tools and they've worked well for me on several occasions. Here's a link to them: http://www.northerntool.com/shop/too...3374_200263374

Wire brush and spray the bolts with PB Blaster penetrant, and let them sit a while. And using a torch to heat the bolt heads and the area around them red hot as was mentioned is one of the best things you can do. Don't overdo it, since you don't want to torch away or melt any metal. Another trick after heating the area is to apply some wax around the bolt head. Some wax will wick into the hole and help lube it. I use Gulf Wax sold at Kroger, and elsewhere. Then choose the bolt grip socket that fits the head of the bolt best and tight and jam it on by tapping it with a brass hammer or hammer and piece of wood. Then try ratcheting the bolt out. It's still likely a couple bolts will break, but at least you'll get the head off.

[gtofreek]

14mm is a little smaller than 9/16"[.5512" compared to .5625"]. Like others have said, try heating, then spray some WD-40 or other penetrating oil on it while it's hot, This will help to break it loose.

[Ben M.]

Originally Posted by Grand73Am

And using a torch to heat the bolt heads and the area around them red hot as was mentioned is one of the best things you can do. Don't overdo it, since you don't want to torch away or melt any metal. Another trick after heating the area is to apply some wax around the bolt head. Some wax will wick into the hole and help lube it. I use Gulf Wax sold at Kroger, and elsewhere.

Just to reiterate, ONLY oxy\acetylene gas will work. Propane and map gas won't get the bolt hot enough to do a thing. Not everyone has access to it, which makes this a difficult proposition at home sometimes.

[steve25]

Since those manifolds are nothing special if need be use a big ball peen hammer (the ball end) and just break them down into smaller pieces , this in and of itself may provide more access to work on the bolt heads!
Be sure to ware eye protection!
If worse comes to worse then it's time to pull those heads and then use a truly big ass punch on the head of each bolt and the pounding will jar the threads loose and you will then get them out even with a vise grip if you have to!
In fact giving the age of the motor it may be a good time to pull the heads and at least change the valve seals and pop on new springs!

[pontiacstogo]

On my 74 T/A I ended up with several bolts where the heads had brittled away. I ended up contacting a friend with portable Oxy - he heated the bolt heads up until they were glowing then hit them with air to effectively blow the bolt heads off - we were then able to slide the manifolds off and remove the remaining 'studs' with heat and vice grips.

It was a bitch of a job with the engine in the car. I was fortunate enough to have the front fenders, brake booster etc. off the car at the time.

[2002Z4CSS]

The bolt heads are corroded smaller than they were when new. Try heating the bolt and many times it will loosen after it cools. Use only a good 6 point wrench or socket and if too rounded off use vice grips to break it loose before using the wrench or socket again.

[TedRamAirII]

Originally Posted by Doug

Since the engine is installed you probably don't have much maneuvering room, even for hammering. One thing you may want to try is cutting/grinding the heads of the bolts off with a Dremel or cutoff tool and sliding the manifold out? off? Even if you don't clear the bolts you can cut them off as needed leaving enough of the stems to work with using use vice grips or pipe wrench to turn the bolt studs (after heating them or applying penetrating oil doses). EASY does it!

When you install the longbranch, make sure there are enough hole-threads so the bolts can be fully torqued. (The holes are not threaded all the way to the bottom.) Also, you should use the "thick" solid washers that are used on some Pontiac manifolds.

Good luck!

DITTO. Muffler shops are not good at Manifold Removal. Most are hacks and dont work on anything above the head pipe. They go after the quick in and out pipes and muffler job. It takes finesse and the correct tools to remove them without breaking them off. If they dont turn out without enough effort to break them loose, stop right there and grind off the heads, pull the manifold away from the head, then cut off the remaining portion, just like mentioned above.

[gtofreek]

Originally Posted by Ben M.

Just to reiterate, ONLY oxy\acetylene gas will work. Propane and map gas won't get the bolt hot enough to do a thing. Not everyone has access to it, which makes this a difficult proposition at home sometimes.

Very true for oil gallery plugs. It does help with regular bolts to heat with a propane torch.

[gtofreek]

Snap-on sockets and wrench's will take off rounded off bolts when no other wrench or socket will.

[Sirrotica]

Originally Posted by TedRamAirII

DITTO. Muffler shops are not good at Manifold Removal. Most are hacks and dont work on anything above the head pipe. They go after the quick in and out pipes and muffler job. It takes finesse and the correct tools to remove them without breaking them off. If they dont turn out without enough effort to break them loose, stop right there and grind off the heads, pull the manifold away from the head, then cut off the remaining portion, just like mentioned above.

That's a pretty broad statement covering all muffler and exhaust shops and labeling them all hacks. That may be your experience, however someone that deals with rusted thin exhaust bolts on a daily basis is going to be much more skilled at removing them than someone that does it a few times in their lifetime.

Any reputable muffler shop will have better removal tools and more skilled technicians than someone doing it at home for the first time. Sorry, I don't agree with the hack statement as I've worked for and known many other people that have owned as well as worked at muffler shops that aren't hacks.

I've removed more broken, rusted, corroded bolts in 45 years of wrenching than most people on here ever will. When I was 20 I worked at a muffler shop for about 6 months and got most of my training removing exhaust bolts without breaking them off in the manifold or head at that shop. I also perfected removing broken bolts that someone else broke off at home trying to save themselves money by doing their exhaust themselves. After they break the bolts off, then they want someone else to get it out for them. Been there, done that, too many times to count.

[TedRamAirII]

No muffler shop in this area will touch a manifold. They dont want the problems. Most have broken bolts and they are warped, cant be fixed, rusted, broken bolts broken off in the head. They dont even own a drill. There isnt anyone over 30 years old that works at one. all they want to do is install Flowmasters or oversize SS Mufflers on Rice burners. All of them will refer a manifold issue to a general repair shop. I get plenty of work from them. I replace the manifolds and send them back. If you have a muffler shop like that near you, you are the man. : )

[Ben M.]

Originally Posted by gtofreek

It does help with regular bolts to heat with a propane torch.

The last 4 broken bolts I've had didn't budge one inch due to propane or map gas even after 20-30m of letting the torch go on it. Had to drill and grind them out unfortunately.

[Sirrotica]

Originally Posted by TedRamAirII

No muffler shop in this area will touch a manifold. They dont want the problems. Most have broken bolts and they are warped, cant be fixed, rusted, broken bolts broken off in the head. They dont even own a drill. There isnt anyone over 30 years old that works at one. all they want to do is install Flowmasters or oversize SS Mufflers on Rice burners. All of them will refer a manifold issue to a general repair shop. I get plenty of work from them. I replace the manifolds and send them back. If you have a muffler shop like that near you, you are the man. : )

Well consider your in FL and I lived in Erie PA the majority of my life there is a bunch more water, salt and corrosion in the rust belt. Anyone that works on cars has to contend with rust on a daily basis. That's why it's called the rust belt, because everything exposed to the elements rusts and corrodes very quickly and is always difficult to remove fasteners made of steel or iron.

Removing manifold to head bolts is little different than removing the head pipe to manifold bolts in a rust environment. Either will break if frozen in the cast iron threads. A frozen bolt in cast iron is just as difficult to remove from a cylinder head as it is from the threaded portion of an exhaust manifold. They're both 3/8 X 16 bolts and usually grade 2. Either is quite easy to twist off if you don't heat the cast iron cherry red first and tap on it with a hammer before trying to back it out.

I've never frequented a muffler shop in FL, but I have in the rust belt frequented many shops as well as worked in them and run my own garage. If you can't deal with rusty bolts on a daily basis you might as well sell your tools and find another profession. To make a blanket statement that all shops that do exhaust work predominantly are hacks and aren't able to change an exhaust manifold is quite a prejudiced statement. I've pulled more than my share of exhaust manifolds and removed broken bolts on any part of a car in the 45 years I've made my living as a mechanic, both in a regular full service garage, dealerships, as well as my 6 months in a muffler shop and always had to deal with rusty fasteners daily.

Last I knew there was no age limitation to remove or learning to remove rusty frozen bolts from cast iron. By the time I was 30 I had perfected removing any rusted bolt on an automobile, or broken off bolts from someone failing to use heat to release the corrosion bond. Sorry you live where people pawn off their difficult jobs on someone else, but where I come from you had to be able to do the whole job, not just the easy stuff.

The OP doesn't have his location in his information, If he's lucky he may live in the North where in a competent shop they do all of the exhaust work from the heads to the tailpipe, not just easy stuff.

OP, I guess if you live in the south forget about taking your exhaust manifold removal to an exhaust shop. From what Ted says they won't touch it, sorry for the bad info. On the other hand if you live in or around the rust belt you may find an exhaust shop that knows how to work on the whole exhaust system, not just the gravy work.