: 1973 472 exhaust manifold bolts ? how do I get to them?

08-30-10, 11:18 PM
Ok I got the replacement exhaust manifold bolts and the gasket to go about taking care of the 2 broken bolts. The only problem is getting to the other bolts to take them out. Is there a trick to doing this besides using a 6 point wrench and breaking more of these buggers off? A swivel socket won't work neither will extensions.



08-30-10, 11:27 PM
You can grind down one of your 6 point sockets or use a 6 point combo or a lugging wrench and a hammer. Lugging wrench is a 6 point wrench with a shortened handle. You hit it with a ball peen hammer to break rusted bolts free.

08-30-10, 11:51 PM
Can you go through the wheel well?

08-31-10, 01:47 AM
One way, if you have the tools for it, would be to take the motor mount bolts out and raise the engine a little with a hoist. This may seem a little much but I have a feeling it may be one of the best options. Especially if you need to take out broken bolts.

08-31-10, 07:25 AM
Can you go through the wheel well?

The picture is of me trying to go through the wheel well. It is blocked there.

I don't have an engine hoist. Is there any other way like a 2x4 and jack on the oil pan?

08-31-10, 07:34 AM
Do not jack on the oil pan. I used to have a small hydraulic jack and could lift engines from the side of the block against the frame or from underneath on the oil pan rail. Use a plate to spread the distribution of the force on the side of the block or a flat piece of stock on the pan rail.

08-31-10, 08:46 AM
I had to pull the engine to get to mine.

If you find another way, please do tell :)

08-31-10, 11:43 AM
You should be able to get a jack under there somewhere safe.

08-31-10, 11:45 AM
lol, did you add the pics after my post? I swear they weren't there yesterday...

To jack, you can use a piece of wood under the crank pulley.

08-31-10, 06:51 PM
posted the pix at the same time I posted the thread :P

The crank pulley can support that much weight without damage?

08-31-10, 11:04 PM
Well, I would guess yes. Think about the pressure that it takes with each combustion cycle. However, if it breaks, it isn't my fault ;)

You should be fine jacking it up on the front of the pan with a block of wood, too.

BTW, you can get flex sockets that are way shorter than that. You have a regular socket with a flex adapter. You might be good with a flex socket. I can take a pic of one if you need it.

09-03-10, 10:34 PM
I ended up unbolting that triangle shaped thing and can get to the bolts now and one came loose with the impact but the others will not budge. ugh. I also can't jack up the engine as I can't get to the engine mount easily



09-04-10, 12:30 AM
broke off two more bolts

09-04-10, 02:06 AM
With hand tools or the impact? What are the specs on your compressor and gun?

09-04-10, 02:49 AM
the compressor is a 5hp husky. The gun is a craftsman prof. The impact gun only got one loose the rest I had to do with hand tools. I got 3 bolts out and the rest broke. The manifold is still attached somehow though. If I have to pull the head to get the manifold off are the headbolts reusable and is the gasket reusable?

09-04-10, 02:55 AM
If the bolts are all gone or broke, its just the rust holding it together. "if it were me"(disclaimer) a good whack with a BFH should do.

09-04-10, 02:57 AM
If I have to pull the head to get the manifold off are the headbolts reusable and is the gasket reusable?

I hit it a few times with a roofing hammer (one of the bigger hammers you see) I will try a rubber mallet as well.

09-04-10, 03:12 AM
You shouldnt reuse the head bolts and you dont want to reuse the head gasket. But if you take the head off, you will need a top end gasket set anyway because the intake, carb and valve covers need to come off.

09-04-10, 11:58 AM
The bolts could be broken in the manifold, so the manifold must come out from the head using a pry bar. The stubs will stop the manufold from just dropping off. This would be a good thing, though, since you will have something to grab with vise grips to unscrew! You have disconnected the exhaust down pipe, correct?

I am not looking forward to doing this on my 81...

09-04-10, 02:14 PM
Yea I disconected the down pipe. The downpipe on the other side is rusted to the manifold and no clue how to get it loose.

09-04-10, 02:24 PM
lol So you DEFINITELY aren't making it to Hooter's tonight.

At least not with the Hearse. :D

09-04-10, 04:25 PM
Sting, LOL, doesnt look like it!

09-04-10, 04:34 PM
I am still working on it <.< the manifold budges like a fraction of a mm but thats it. I also left the interior light on the last time I used it so the battery is flatlined

09-04-10, 05:51 PM
Hey! I did that yesterday too! :(

09-06-10, 05:09 PM
The manifold moves a tad bit more but one bolt where the head only broke off is holding it there. I tried an easy out screw remover and it broke too. <.< I tried a BFH and a crow bar and any more pressure and I will break the manifold.

09-06-10, 06:51 PM
Use a reverse thread drill bit on the bolt where it is stuck.

You sure all the bolts are out? No accessory supports, etc?

09-06-10, 07:03 PM
We had the same problem with mine. We hit it with a splitting maul and that broke it free, but also chipped the manifold a little and we had to braise it. works fine though.

09-06-10, 07:20 PM
because of the location a drill can't get in there unless you use a flex extension. Already broke the broken bolt extractor as well as the flex bit thing haha. Everything is disconnected and the manifold wiggles besides the one screw.

09-06-10, 07:49 PM
Maybe a big ol prybar/tire iron? So is there something blocking it from coming straight out from the bolt? Part of the head still on the bolt?

09-06-10, 08:26 PM
Maybe a big ol prybar/tire iron? So is there something blocking it from coming straight out from the bolt? Part of the head still on the bolt?

tried a crow bar if you read up. Nothing is blocking it that I can see. Also the entire head broke off.

09-06-10, 08:57 PM
Well, something has to be stopping it. To be clear, you can get the entire manifold to move a bit away from the head? And, you have dropped the exhaust pipe off the manifold, correct?

Maybe take us some more pics from the top so we can get our heads around this...

09-06-10, 09:43 PM
just a thought on this, when u drilled the hole for the extractor maybe u missed the center of the bolt a little bit and started a new hole and the broke off extractor is holding it tight maybe..kinda like a wedge

09-06-10, 10:10 PM
It was stuck before the extractor thing broke. I'll try and get some pix tomorrow. I can't pull it outward but I can move one side maybe 1 cm upward then 1cm downward. The bolt seems to move with the head. I tried wedging the crowbar under it to force it to move farther but nothing. I even tried prying between the head and the manifold. I also disconnected the exhaust and that is laying on the ground :P

09-06-10, 10:27 PM
Ah...I see. That may be a tough one unless you can get an open ended saw to cut the bolt. Any room between the head and manifold? So the bolt is rusted to the manifold but turning in the head?

09-06-10, 10:29 PM
it looks to be turning with the manifold but can't tell for sure with only 1cm of play. I tried to fit a hack saw blade between but there is no room.

09-09-10, 11:23 PM
Well this has to be the most time I have ever spent on any one specific problem. I still don't have it off but the manifold moves a fair amount more.

09-10-10, 09:23 PM
After a couple weeks working on and off I got it. I had 2 mechanic friends look at it and fail too. Below is all it took.

5 bolts
2 cans of pb blaster
4 drill bits
3 broken bolt extractors
2 hacksaw blades

Used but still alive
sledge hammer
drill press
metal bar/ punch
air chisel / impact

I still have the 5 bolts that are broken off inside the head to go but the manifold is off.




Should I remove what i guess is the head bolt before drilling out the bolts stuck in the head? Do they go up against each other? See below.


09-10-10, 10:35 PM
Is that an extractor inside that bolt?

09-10-10, 10:42 PM
Congrats! I know the feeling of finally conquering a monster problem.

Do you have a MIG welder? If yes, you can hold a nut in place over the broken bolt, weld the nut to the bolt, and then back the bolt out. The weld will not stick to the cast iron head.

If you broke off and extractor in there, you might be in trouble. They are very hard. If not, you can try reverse drill bits. Sometimes the bolt will spin out with the drill bit. If it doesn't, keep drilling bigger until you can pick the threads out, then chase the threads. You must drill right in the middle of the bolt.

09-10-10, 11:15 PM
How can you weld if the broken part of the bolt is flush with the head?

one of them has the easy out broken off inside it yes. The other 5 don't.

09-10-10, 11:26 PM
You weld in the center of the nut and stick it to the bolt.

With 5, and a broken easy out... I might think about grabbing another head.

09-10-10, 11:28 PM
I can't afford another head.

09-10-10, 11:52 PM
Broken bolt how-to (http://www.asashop.org/autoinc/may2003/techtotech.htm)

Read the whole thing, paying attention to "Worst Case Scenario".

09-11-10, 12:06 AM
I know one of my friends has a stick welder... I can see if he can bring it over... otherwise I gotta keep trying by hand.

09-11-10, 09:43 AM
Yay! good job, man. And you don't have to remove the head bolt before drilling out those broken bolts. Good luck!

I ended up just drilling and tapping the holes.

10-09-10, 01:32 AM
tried the welding thing and he could not get it to stick. I tried for a day myself as well and failed

10-09-10, 11:57 AM
You need a MIG welder.

10-09-10, 02:15 PM
can't afford that