Ideas on how to remove a couple exhaust studs

[jcgribks]

Thought my local GM big truck center had replaced all the exhaust studs, at least I paid for all new studs. Got all the new studs out ok but found 2 original studs he didn’t replace.

Nether are broke and both had new nuts installed. One looks to be not installed all the way or has longer threads that go into head. It also looks like vice grips have been used on it before. Hers a picture of both

Needing ideas on how to remove them without them breaking. That’s why I took it to the dealership as I didn’t want to have to deal with broken studs.

[MrMark52]

Soak for several days with a 50/50 mixture or transmission fluid and acetone. The longer you soak, the greater the chances they will break free.

This assuming you've got some time and not trying to get on the road.

A little background - had some hood hinges on our ‘91 coach that consisted of 2 body anchored blocks either side of longer tongue block that attached to the hood - all held together with a 3/16” pin. Couldn’t budge either one and ended up ripping the anchor blocks out of the fiberglass.
When I finally got access so I could remove the assemblies, I put them in a bowl of the above mixture and sealed the bowl tightly. Every once in a while I’d jiggle the bowl.
A month later, I opened the bowl up - and as I lifted the hinge pieces out of the bowl, they fell apart - the anchor blocks easily slipped off the pin, and the pin easily fell out of the tongue piece.

As with any product, LiquidWrench, PBlaster, Kroil, WD40? - it’s all about time and patience, with maybe a little occasional heating/cooling to the stud added.

[wolfe10]

Removing old exhaust manifold studs can be an ART FORM.


Absolutely soak with a good penetrating oil for a week if you have the time (couple of drops each day),


Then, "worry" them-- loosen/tighten a little, but never to the torque that could break them. More penetrating oil.



Maybe light, sharp raps on the end of the stud (or on double nuts on the end). Maybe heat head around the stud and ice on the stud.............


Again, this is about being patient and finessing rather than brute strength.

[CamJam1]

Originally Posted by jcgribks

Thought my local GM big truck center had replaced all the exhaust studs, at least I paid for all new studs. Got all the new studs out ok but found 2 original studs he didn’t replace.

Nether are broke and both had new nuts installed. One looks to be not installed all the way or has longer threads that go into head. It also looks like vice grips have been used on it before. Hers a picture of bothAttachment 363475Attachment 363476

Needing ideas on how to remove them without them breaking. That’s why I took it to the dealership as I didn’t want to have to deal with broken studs.

This is not the exact same scenario, but about three weeks ago I had to remove the nuts off the exhaust manifold of a 50 year old car, and I wanted to be sure not to break the studs. I spent a lot of time researching the best way to go about it and I started out soaking the nut and stud in Deep Creep penetrating oil. I understand Croil is even better but couldn't find it locally. I did that for about 24 hours, reapplying the Deep Creep periodically. The next day I heated the nut red hot with a propane torch, quickly followed by freeze-it in a can, then more heat, more Deep Creep, then let it sit for a few minutes before repeating the process. After about 1/2 hour of that I got the nut very cold with freeze it before removing the nut with an impact wrench. I did all four nuts this way without breaking a stud.

In your case maybe you could spot weld a nut to the stud? Heat the block and freeze the stud to try to break the bond between the two. Be sure to use a 6-point socket, otherwise the impact wrench will just round the nut off.

A yellow MAPP cylinder will produce a much hotter flame than the cheap blue propane cylinders. Acetylene is even better.

[jacwjames]

Use some sort of penetrating oil, I used PB Blaster but there are other. Soak it for several day.

Try double nutting it, screw two nuts on it and then back the first one out until it contacts the second one and they will lock. Use the outer one first and try tightening the stud in a little to see if it moves. Then use the first one to turn the stud out. Do this back and forth and see if you can get to to loosen without breaking it.

[Alan_Hepburn]

How about taking it back to the shop - you paid to have all of them replaced and it sounds like they didn't complete the job...

[Alpine36]

Heat red hot, Kroil quench, repeat. More Kroil and time. Smack the end of the stud squarely with a hammer several times during this process.
Broken studs can be removed with a cutting torch, but that's an acquired art form taught mostly by old Ford mechanics lol...
I'm from the school of "if it ain't broke don't fix it", and can sympathize with your mechanic. I wouldn't have replaced the good studs either, unless you specifically requested it to be done, at an extra cost of course.

[craigd853]

Originally Posted by jcgribks

Thought my local GM big truck center had replaced all the exhaust studs, at least I paid for all new studs. Got all the new studs out ok but found 2 original studs he didn’t replace.

Nether are broke and both had new nuts installed. One looks to be not installed all the way or has longer threads that go into head. It also looks like vice grips have been used on it before. Hers a picture of bothAttachment 363475Attachment 363476

Needing ideas on how to remove them without them breaking. That’s why I took it to the dealership as I didn’t want to have to deal with broken studs.

Ok sir here you go. Do soak the stud for a couple of days in whatever penetrating oil you wish. The next trick is to heat the stud up using a portable heat source such as the benzomatic torch that can be purchased at Home Depot or Lowes for under 30.00. Heat the stud where it goes into the side of the head, heat this area for approximately 2-3 minutes or until the area turns red and back out stud with appropriate tool. I would try a torx socket first as this is what the end of your stud looks like or a good pair of vice grips super tight. One more tool to use is they specifically make reverse thread sockets that will grab the head of the stud and bite down on it when you start to turn on the stud. Shouldnt have to use a lot of pressure after you have heated the head and stud up properly. Like I said make sure you keep the heat centered where the stud enters the head. If the stud starts to twist or contort stop and reassess the situation. I hardly doubt that you can get that stud out with just penetrating oil but stranger things have happened. Heat is the best way to do this especially since its iron heads. Hope this helps and good luck

[jcgribks]

Originally Posted by Alan_Hepburn

How about taking it back to the shop - you paid to have all of them replaced and it sounds like they didn't complete the job...

Shop about 45 min away but I already have the rest of the exhaust off.

[jcgribks]

Originally Posted by Alpine36

Heat red hot, Kroil quench, repeat. More Kroil and time. Smack the end of the stud squarely with a hammer several times during this process.
Broken studs can be removed with a cutting torch, but that's an acquired art form taught mostly by old Ford mechanics lol...
I'm from the school of "if it ain't broke don't fix it", and can sympathize with your mechanic. I wouldn't have replaced the good studs either, unless you specifically requested it to be done, at an extra cost of course.

I did pay for all new studs. That was why I took it in was to have all new ones put in. I told the service adviser that eventually I was going to put on Banks headers. The mechanic probably thought he’ll never know if I leave a couple of old studs in there.

[oldmattb]

I removed 12 24-year old exhaust manifold bolts with no issues. I used Freeze Off, over a couple of weeks with heating it up a few times. Then followed this:

https://www.youtube.com/watch?v=9PKNCVXvZ6w

[jcgribks]

Ok I’ve soaked both studs down a couple times today using PB Blaster but doing so got me thinking. Both studs are angled down a little so is the blaster going to go up hill into the stud/head??

[bigb56]

Heat cool heat cool will do it. I have a tiny Smith OA torch that I can put heat on a stud with a pinpoint flame, one or two heat cycles and I've had them get so loose you could turn them out by hand. If you can concentrate the heat on the stud the heat will expand the stud against the hole, enough heat and it will soften and "upset", that is it will be forced against the hole forcing some of it's mass to the ends and shrink when it cools. It takes glowing red/orange heat to do this. I realize many don't have access to OA but even Mapp gas will work because as the stud expands and contracts it breaks loose the years of rust.

[klspahr]

We removed a lot of studs in heads when I worked at an automotive machine shop. (We generally had the head on the work bench because we were doing more than just removing studs.) We heated the head area around the stud pretty hot and then clamped vice grips on the stud near where it entered the head - THEN WAIT A HALF A MINUTE - this allowed the vice grips to act as a heat sink and cool the stud faster than the head causing some shrinkage in the stud before we would try to turn it. You may only get a little bit of a turn the first time but don’t get carried away. You can always remove the vice grips and cool them while you re-heat the head. Penetrating oil can also help as it soaks in better once the threads have loosened a bit. I also think the hot metal allows it to go deeper into the threaded hole than when everything is cold.