1972 Exhaust Manifold leak

[gkhashem]

I have run across a very nice 1972 Coupe DeVille that the seller states has a slight exhaust manifold leak. How problematic is the removal of these bolts. The car has 43000 miles..

[TJ Hopland]

You never know for sure but more often than not they don't come out easy.   Questions I would be asking is are there any broken bolts now?  And are there gaskets installed now?   These didn't come from the factory with gaskets so if there are gaskets that means its been apart before.   Being apart is good from the standpoint that it means those bolts have been out at least once in its lifetime but also begs the question why was it apart with fairly low miles. 

Is this an Eldo?  For some reason the Eldo's its pretty common to have cracks. 

[gkhashem]

It’s a CDV actually a very nice looking car looks mint

[chrisntam]

We want to see a nice looking mint '72 CDV, post a link!

You have too many cars already!   

[gkhashem]

That's part of the game I have the first crack at it I think.

[hornetball]

Driver's side cracks are common because of the heat stove.  The manifold is reproduced and readily available (I got one from Rock Auto).  MaR and I are both working on 1974 Eldos.  I had no issue getting my bolts out.  MaR had numerous bolts break.  So . . . you really don't know.  Worst comes to worst, you're pulling heads and inspecting your camshaft and timing chain -- which you probably need to do anyway.

When you put it back together, use some of that copper anti-seize on the bolts for the next guy.

[chrisntam]

snip...

Worst comes to worst, you're pulling heads and inspecting your camshaft and timing chain -- which you probably need to do anyway.

My dad always called that "creeping elegance", when the job went beyond the initial scope of work.

[INTMD8]

On this engine in particular, I don't know.

In general however I have had excellent results removing broken manifold bolts from pretty much everything by holding a nut over the broken stud and filling the void with mig weld.

You now have the hex of the nut to wrench on and the heat put into the broken bolt helps when loosening.

[Big Fins]

I would spray the offending side with PB Blaster, for a few days just letting it soak in. I got the manifold bolts out of my '59 this way. They were frozen in place. After about a week of spraying them twice a day, they walked right out. Same with the tiny brake line connections on my current Eldorado. Granted they weren't rusty, but 43 years under a car can't be great.

[hornetball]

My dad always called that "creeping elegance", when the job went beyond the initial scope of work.

I like that.  I'll have to remember that the next time a 1 hour job turns into a 2 week journey. 

[Scot Minesinger]

Reality is that you should replace the timing chain because it is nylon coated aluminum cam sprocket.  It is very difficult to remove the manifold without breaking a bolt. 

[Big Fins]

Firstly, if a bolt is so stuck that it's going to break no matter what you do, why not go the cheapest/easiest route first. After soaking in a penetrating solution, they might just all come out with ease. Won't you be smiling from ear to ear. If you really want to see the dark side, go in there and try to break them loose like you only have a few hours to get the whole job done. They are either going to come right out or be a total nightmare job. Your call.

If you are that concerned about the chain and sprockets, pull the dizzy, rent or borrow a bore scope and take peek inside. I changed out a 35k mile chain and sprocket assembly that looked brand new, because I was always reading the dark side here. The plus side is, I know it's done with far more superior parts than originally equipped and I hung a new water pump while it was all down.

[chrisntam]

Tell the guy you want to buy the car, but the price is dependent on if the bolts break. 

If they come loose, give him the asking price. 

If they break, deduct $1000.

A little tip from your good buddy Chris.

[Glen]

Removing stuck bolts is a tedious task and must be done carefully.  Many people make the mistake of just trying to muscle it out.  That is the worst thing you can do.  As others have said first soak it with a penetrating oil.  Forget WD40.  The best is a 50/50 mix of acetone and automatic transmission fluid. 
After it has soaked for a couple of days try to remove the bolt. If the bolt moves even just a little bit it will come out in one piece if you don’t rush it.  You still have a ways to go. 
At this point you have to alternately tighten and loosen the bolt. Each cycle the amount of movement will grow.  Keep adding penetrating oil.  Eventually the bolt will come out.
I have spent as much as a month with this process with the soaking taking the majority of the time. 
No pipes on the handle of the wrench. 

[The Tassie Devil(le)]

But, how does one get the penetrating substance to travel up the shaft of the bolt and into the thread, as these Manifold bolts are actually pointing downwards?

Bruce.

[Big Fins]

The rust particle will 'wick' the solution right into the threaded hole. But note...most, if not all are stuck within the manifold itself, not the threaded hole. The shoulders of the bolts are incompatible with the cast iron of the manifold.

[Scot Minesinger]

Another way to remove the bolt is remove all exhaust manifold bolts that will come out and try the soaking and all on the ones that will not.  Failing that, grind off the heads of each bolt and remove the manifold.  Now with manifold removed you can really get in there and soak the threads good and use a stud remover or small pipe wrench to get the remainder of the bolts out.  I find a glancing blow, is better at breaking free stuck fasteners than stead torque, which often make the fastener fail.  With wrench/stud remover in position, hit it with a small sledge (rehearse the stroke and don't wimp out), and the fastener will not break, but it should come loose.  Then of course the ground head manifold bolts can be replaced inexpensively.

[chrisntam]

Did you get it?