View Full Version : help with manifold bolt

May 8th, 2014, 12:57 PM
So basically, a few weeks ago after doing the up pipes, I noticed that there was a bit of an air leak out of the driver's side manifold of my 2001 F350 with a 7.3l diesel. I could feel it coming out toward the back, and I could hear the tick from inside the cab. I checked the manifold bolt torque, and the rear three were pretty loose. I tightened them all up, and ordered a new manifold.

Monday morning, figuring how loose the bolts were, I decided to swap the manifold in the truck. One bolt I had tightened broke off flush with the head, and one other bolt (hadn't tightened) rounded off the head. I cut that one flush with manifold with a sawzall, and the manifold fell to the ground. I used some vice grips after a bunch of PB and got that one out.

Not sure what to do with the bolt that broke, which was the furthest back, I think cyl 8, I drilled a small hole, and got an easy out on it. I cracked off the easy out, and was able to use vice grips to get the rest out.

Next, drilled a bit more of the bolt out, and got a bigger easy out. This one broke flush.

This is now Tuesday afternoon, 9 hours into this project. Start cutting the easy out with a saline torch. Make it in most of the way of the easy out. Threads still look good from the head, but there is a bit of bolt remnants on them, as well as a tiny 1/8" inch remainder of the easy out. Ran out of time at 9:15pm last night.

Today, waiting for my neighbor who knows how to use the torch to get off work. I'm a decent mechanic, but I've made more mistakes on this job (not knowingly until after the fact) than I have in the last 8 years of working on my own stuff, and the stuff of others. This makes me terified to touch another thing on the truck until someone who knows how to use the torch comes over. Once that bolt hole is clean, I'm good to go finishing up the project which should only take 30-45 minutes at that time to mount the new manifold.

I'm really freaking out that that hole isn't going to be fixed, and I'm going to have to pull the head off to have it re machined. Someone suggested boring through the cast iron, and using a heli coil. I tried that about ten years ago with a spark plug, and had a horrible result.

Current plan is to go at it again with the torch, to finish removing the cracked easy out which still has about 1/8" inside the hole. Then use a drill, and remove as much of the old bolt as possible. After, try a thread chaser or tap to remove the old bolt material, hoping to salvage the threads on the block.


May 8th, 2014, 06:46 PM
a acetylene cutting torch with a small tip is what I use, the torch will melt out the steel bolt & EZout and not damage the cast iron threads
using a thread chaser is a must

next time let it soak longer and use some heat to remove the nuts
they do make a nut splitter but is hard to use in tight places

a HeliCoil if using the right dill bit and tap work well
a better alternative to the HeliCoil is a TimeSert a little more expensive but are superior, I use them on cast iron & cast aluminum

its scary tapping a spark plug hole, use plenty of grease on the tap to hold the metal shavings and clean off every turn or two
use a small tube taped to a vacuum hose to get anything out of the combustion chamber

also if you do have to drill the stud hole out work up with progressively larger bits to the correct size, this will help a little to keep the bits from binding and breaking off and will also help to drill the hole straight , use a right angle drill and low RPM's, a drill with a clutch helps from breaking the bits

good luck and add some hi-temp nickel anti-seize to the studs and nuts when you put it back together

May 9th, 2014, 12:53 PM
Thanks for all the help. I'm hoping the torch thing works. I bought a set of thread chasers, and hopefully they come in soon.

Question about the cast iron threads though. I looked up some of the metal properties, and cast iron is supposed to melt like 400 before steel. How am I going to be able to melt the steel bolt without damaging the cast iron threads? Is it just that I'm concentrating the tip on the stainless, and just go slow?

May 9th, 2014, 01:38 PM
you are correct, but it works, try it on an old head
I've never melted cast iron, and have burned out many broken studs & bolts from cast iron
just stay in the middle of the hole and try not to burn the threads
that's why I use a small tip
also the torch temp can be regulated down by increasing the acetylene and reducing the oxygen, do this adjustment while holding down on the O2 supply/cutting lever

here's another way to do it if room is available

get a nut with an ID the same as the stud, place it over the stud and weld through the nut onto the stud; connecting the stud to the nut
let it cool slightly and remove the broken stud out using the nut

May 9th, 2014, 01:44 PM
I did, it's 2600f for stainless, and 2100f for cast iron. I'm going to try it, just was curious based on the temperatures. After, just use the thread chase and I should be good?

May 9th, 2014, 02:01 PM
I edited about the temps above as I also checked and added to the above

this all hinges on the skill of the person working the torch
it is possible to lose some of the thread height meaning the edges of the threads many burn off
just remember the one you burn needs to have a bolt tightened slightly after you chase it, using washers so it doesn't bottom out and check the tightened torque value
you many not want to tighten this one more than 30 ft/lbs

if it fails it's HeliCoil or TimeSert time

May 9th, 2014, 02:48 PM
The torque spec is 45, you think 30 then?

May 9th, 2014, 04:25 PM
you don't want to pull the threads as they have been heated

but it may go higher than 45, but.... stay on the safe side
that's why I say to torque as much bolt in there as you can before you install the manifold

May 9th, 2014, 04:32 PM
you may want to use a thread locker sealant
my thoughts are Loctite 263 but I'm not sure it will work with exhaust temps

see this


May 10th, 2014, 07:47 AM
keep us posted

May 10th, 2014, 10:18 AM
Will do. Should be finishing up with the torch tomorrow morning, and I'll post up the results.

Since the R drill bit (proper size for a m10x1.5) is almost impossible to find, and the 11/32nd is a little larger, I was going to use a 21/64 to make the final hole before hitting it with the thread chaser. I figure that over the 11/32nd, because I want to hurt the original threads as little as possible...


May 10th, 2014, 02:39 PM
I've only used the torch followed be a starter tap then the thread chaser
the starter tap worked back & forth helps to get the metal out,
its also helps to grind the tip off the started tap down to the first taper thread that way it will go further into the hole before bottoming out, this tap helps to get small trash out
the thread chaser is more than likely going to bind up as it's a tight fit
back & forth/in & out is the key, use compressed air to keep the hole clean
I don't use a drill bit

I would suggest you find an old head or block - something cast iron, and break or cut off a bolt or stud , flush like you have
and do a practice run or two before you dive into your good head and screw something up
this will give you a learning curve with the torch
it's going to be hard to do that rear port next to the fender well as you won't be able to see what your doing

think about it and don't rush into it

like riding a Horse it's hard the first time but gets easy after a time or two

May 11th, 2014, 07:08 AM
I want to add
do a practice try; and make sure the hole is on the horizontal or slanted down hill if not the slag will pool in the hole and be harder to blow out

May 12th, 2014, 09:12 AM
The hole is in the motor, which is inside the truck, so my ability to change it's angle is quite limited. There isn't much easy out left in the hole, if any. I tried to hit it with some cobalt bits from Home Depot, and the bit isn't even cutting. I don't even think it's made a mark on the bolt. This project is very frustrating for me, and I'm getting tired of wasting my time on it. I think that I may inevitably just pull the head out of the truck, take it to get machined, and then reinstall it with the hole corrected. If I can't drill out this hole, I'm not sure how in the hell I can drill it out for a tap, let alone drill it out and get a freaking helicoil in there. I'm not sure how people have suggested that one, because I can't even make a pin hole in this bolt hole after the easy out went in there.

May 12th, 2014, 09:29 AM
your not going to be able to drill the easy-out due to the hardness of the metal

I meant on an angle to do a practice on an old head or something

if you going to think about taking it apart do the torch first
you will be surprised how well it will work
get out the torch and you will get that easy-out, out along with any stud

May 12th, 2014, 09:35 AM
I've got the torch. My buddy hit it it saturday night for about an hour, and only got about 1/8" further in the hole. Said something about the metal pooling up, and it wouldn't drain because the torch was pushing it further into the hole.

May 12th, 2014, 09:48 AM
you need to turn the O2 & Act.up a tad
raise the truck up on the other side to help it drain out

May 14th, 2014, 11:57 AM
I had a horrible stomach ache on Monday, so my friend being a bad ass friend, used the torch and went to town. Then had an idea of using a die grinder to get the remainder of the Easy Out out, which worked well. Today I cleaned the hole a bit more, and am getting ready to tap it. A t handle isn't working, so I'm getting ready to swing by Napa to get the tap socket set. Expensive at $35, but I'll be able to get the ratchet in there and should make this a lot smoother. It's so hard to get the tap handle in there, I'm afraid I'm going to break the thing off.

May 14th, 2014, 12:43 PM
I had a horrible stomach ache on Monday, so my friend being a bad ass friend, used the torch and went to town. Then had an idea of using a die grinder to get the remainder of the Easy Out out, which worked well. Today I cleaned the hole a bit more, and am getting ready to tap it. A t handle isn't working, so I'm getting ready to swing by Napa to get the tap socket set. Expensive at $35, but I'll be able to get the ratchet in there and should make this a lot smoother. It's so hard to get the tap handle in there, I'm afraid I'm going to break the thing off.

unless it's a shorter length tap, a 1/4" drive 12 point socket will fit on the square tap end; don't remember the size though

May 14th, 2014, 02:05 PM
I got the tool and I'm starting the thread cutting. It's pretty apparent that the bolt hole isn't PERFECTLY straight in, but it's really close. I've got maybe a 1/32" more metal on the bottom that I'm cutting vs the top. I'm wondering how far in I really need to go, and if it's possible for me to just use washers, and space out the bolt like 1/4-1/2" instead of risking cutting into the block any further. Thoughts?

May 14th, 2014, 03:34 PM
you said that you could not drill the hole
so the hole is only so deep, go all the way with the tap, it will stop when it gets to the bottom
you don't want to risk pulling the threads out with a short insertion of a new bolt

May 15th, 2014, 09:19 AM
Job is done. The hole was on a little bit of an angle, and I didn't want to keep cutting with the tap, as I was afraid it would cut off too much metal and break the tool. I went down pretty far, and was only about 3 threads from the bottom when it pretty much stopped and would turn at all. It was a judgement call, and then when I put the manifold on, and the bolt, I found it was going as far into the hole as it could anyway. I did throw a washer between the bolt and the manifold, just in case. I want to thank you for all your help. Next truck project, after I fix the boat, is going to be the front end stuff. It's extremely loose. Thanks again!

May 15th, 2014, 09:04 PM
we know about boats also

I had many over the years, 12' - 26'; as have other members

one member works in a Marina and also builds boats

May 15th, 2014, 09:15 PM
Aaron is the one that referred me!

May 15th, 2014, 09:21 PM
oh, well I'm sure we can't be that much help then; where ya from ?

by the way, glad to hear ya got the manifold back on

May 15th, 2014, 09:49 PM
Lol, no I'm sure you all can help. Just wanted to say that he was the one who referred me as you mentioned him. I'm down in the Tampa area.

May 16th, 2014, 10:25 PM
Well..... Anyone care if I add my two cents for future broken bolts? Lol...too bad....I'm going to anyhow!
My experiences.....if you use an easy out that is half the size of the broken bolt, and it won't break loose....don't try the next size....it won't work either 99% of the time. If you break an easy out off, stop and cool off! It's gonna be a pain from there! If you done as advised and used a bit half the size of the broken bolt, you will have room to drill small holes around the broken easy out to weaken the surrounding metal. When the surrounding metal is weakened, you stand a better chance of being able to take a angled chisel to work the easy out loose and once it's out, you can collapse the small amount of metal that's left.

Furthermore, If you don't have an easy out broken off (not everyone has a set) it's much easier to just drill the bolt out in increments up to the size of what the heli coil requires. When drilling for them, drill straight....and SLOW!!! The sharper the bit...the better too! Heli coils are great for manifold repairs as well! I have used them plenty of times.

When your trying to remove one again, try rocking the bolt or stud instead of brute force to just assume it's going to "just break loose"! I've seen plenty of guys do that in my shop and they ended up in your situation. Then I'm get to be the lucky one to drill, beat and bang to fix it because their lost with no idea of how to fix their eff up.

Also something to keep in mind..... A concrete bit will remove an easy out but takes a lot of patience and time.

Just my two cents!

May 16th, 2014, 10:32 PM
two cents + change

where the hell ya been

May 16th, 2014, 10:43 PM
Been busy as hell!!! Working 60hrs a week, garden, kids, 2yards to do up keep, 4 vehicles to keep up. Getting things lined up to open my own shop in the near future!!! I hardly have time to take a piss. I have built or overhauled 6 engines in the last 2 months not to include anything else they throw at me on top of wrecker calls.

I'm tired of being the lil colored boy making someone else rich! I'm ready for all the cash to be in my pocket.

Was sick first part of the week. Trying to play catch up now.

May 16th, 2014, 10:48 PM
get better
keep the good Thought$

and get a catheter and a piss bag to hang off your pocket

garden, kids, Trucks = fun

May 16th, 2014, 11:58 PM
Hey,Cat Good to hear from you. get ta feelin better you need to pop in more often.
JS needs an antagonist partner HAHAHAHAH God Bless

May 17th, 2014, 08:10 AM
sorry for the Thread hijack it doesn't happen often

May 27th, 2014, 08:55 AM
dont apologize to me! That's what forums are, for discussion!

May 27th, 2014, 11:04 PM
:goodpost: but dont :feed2: