How I got Exhaust Manifold bolts out without breaking any

[aandpman]

So a few weeks ago the passenger side (rt) exhaust manifold showed the signs of being cracked/broken (the usual ticking, etc. It was in the typical place - right between the two front runners. Knowing that replacing this on a 27-yr old truck could prove to turn into a nightmare of fatigued/rusted/broken bolts, as visions of e-z-outs danced in my head, I had to invent a way to carefully remove these bolts.

1. Get all the usually junk out of the way to expose the top of the exhaust manifold (brackets, plug wires etc)
   
2. Get out the drill and a long (6" or so) drill bit (probably a 1/8" - I didn't honestly look)
3. Locate the areas of the exhaust manifold just above the bolt journals that the bolts go thru that attach to the head.
4. Drill holes perpendicular to each bolt journal somewhere around the middle, taking care to intersect the journal. Drill thru until you the bit get into the journal. You want to stop short of drilling into the bolts/studs.
5. Insert the handy-dandy red tube that comes with your can of PB Blaster into each of the holes and spray until PB Blaster squirts out of the holes. It doesn't take much. Your goal here is to actually get penetrating oil to where it will actually do some good - the threads going into the cylinder head. Just spraying it on the bolt heads couldn't possibly get any to the threads.
6. Let this sit for a while and maybe give the holes a second squirt.
7. Get out your breaker bar and a rubber hammer.
8. Put the breaker bar and a good 6-point socket on the first bolt/stud.
9. GENTLY tap near the end of the breaker bar like you are trying to break the bolt loose. You may have to tap for a while, and gradually increase your tapping force, but eventually you'll start to feel some movement. Keep going until the bolt is starting to break free. DON'T get over-zealous, as putting too much torque at one time on these old heat-fatigued fasteners will surely snap them.

This procedure saved my bacon. I got all 6 bolts out of the passenger side manifold without breaking off a single one.

 

[diesel4me]

When I took apart vehicles at a junkyard,we had to get things off quickly,yet without doing any damage or as little as possible..

Most of the time exhaust manifold bolts dont break off or seize in the heads,its where they pass thru the manifold casting,where you drilled them and lubed them up good with penetrant..nothing wrong with that method,though it'll take a lot longer..that passage fills with rust and the manifolds often warp and put side loads on the bolts too,encouraging them to snap off..

When we needed to remove an exhaust manifold,we used the torch to blow the heads off the bolts--then pried the manifold away from the head with a pry bar (gently of course)--after you get it to start moving ,and the bolts would come free from where they pass thru the casting,the manifolds would come right off...if there was not enough room to slide them off without hitting the frame,you'd have to cut the bolts again just behind the manifold..then it could be lifted out..(leaving some "stubs" sticking out of the head so you can get the remains out later)..

On vehicles that we were replacing old cracked exhaust manifolds on,we often used that method,or in extreme cases,we took the sawsall to the old junk manifolds and sliced them and the bolts,lengthwise--this may sound difficult,but with new sharp blades,old thin cast iron manifolds cut very fast and like butter,the bolts can be a bit tougher..

Most of the time once we got the manifolds off,we could unscrew the remains of the bolts out of the heads with our fingers !--sometimes you'd have to take a vise grip to a stubborn one,but they usually all came out without breaking off or having to be drilled..these were older cast iron engines ,aluminum heads will likely prove more of a challenge to get the bolts out intact...the LS engines have a sucky design,tiny bolts in an aluminum head,they snap off like peanut brittle even if you use heat and patience often..

 

[aandpman]

Good insights there... problem is, i don't have a sawzall or a torch, and I don't presently have a 20 amp outlet to plug my HF special welder into. :-)

 

[diesel4me]

That sucks--it would be hell if you had to use these 2 tools to drill broken bolts out...

We often couldn't use a torch out in the yard,with lots of pine needles and leaves,tall grass,etc piling up around the junked vehicles--it was the cordless sawsall or drill,or nothing..

I also got pretty good at using cold chisels and a hammer to shear off bolts in such circumstances..my co-worker's favorite "rivet buster" for chopping off shackle and cab mount brackets was a all steel camping hatchet he found in the trunk of a junk car--he'd just place it between the frame and bracket,and whack the hammer end of the hatchet with a 5 lb. sledge..
Three or four good whacks,and the rivet was sheared,with little damage to the bracket..I always stood way back and looked away when he did that.....thing worked great though,and didn't shatter..

 

[Big Ray]

I soak mine a day or two with the PB blaster...about mid-week. I usually work my rigs on the weekend.