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Technical Removing Brass Nuts on Old, Rusted Exhaust Manifold Flange Studs

Discussion in 'The Hokey Ass Message Board' started by MrCreosote, Sep 28, 2021.

  1. MrCreosote
    Joined: Jul 23, 2009
    Posts: 283

    MrCreosote
    Member
    from USA

    I'm guessing these nuts have been on for 10-20 years. Back back around 1970, I was messing with the factory brass nuts Studebaker used and one of the failures was the stud would pull the threads out of the nut. But this is more indicative of living near Pittsburgh in the RUST BELT.

    I know all the tricks to take steel nuts off steel studs - have all the oxy-acetylene gear and experience and methods to create big thermal gradients to cause relative expansion and the shattering of the rust crystals. Paraffin to solve the galling (screeching) problem if encountered.

    But with brass I'm not so sure since since developing my skills, I've never dealt with brass nuts on decades old rusted studs.

    I just bot the 1800w Bolt Buster and am thinking this may be THE way to do this because if using a torch, it's impossible to heat the stud w/o heating the brass even more. No chance of getting stud glowing using gas - the nut will melt.

    My initial plan: (all heating is induction w/Bolt Blaster)
    1. Heat stud for 2x the time to burning oil smoke
    2. Spray cold water from pressurized pump sprayer
    3. Cool to room temp
    4. Repeat 1-3 a few times*
    5. Repeat 1-3 a few times* substituting Free All "rust dissolving" penetrating oil
    6. Repeat 1-3 once and wick paraffin in.
    7. Using impact gun on lowest setting (far below breaking stud of stripping threads) to shatter rust crystals with the impacts.
    * - with every cycle, there should be lessening heat conduction from the stud to the nut, so slowly increase the temp stud is heated to.
    Really need to know other tricks since right now, this is on my only daily driver and I must get the nuts free for the exhaust shop to weld up a stock stainless system. NOTE: If the studs get broken, I'm going to be the one to break them!

    And if a stud breaks, I'll have to pull the manifold and probably replace the gasket which also means pulling the intake and yes, there are THREE different gaskets that could be used and YES, they have to be mail ordered.

    Thanks in advance,
    Tom
     
  2. I needed to get some ancient brass nuts off the crossover pipe on my '50 Ford. They wouldn't move by hand. I heated them up with the torch until they were glowing red. They all came off with the impact while still hot quite easily. 3 of 4 would have been re-usable.
     
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  3. squirrel
    Joined: Sep 23, 2004
    Posts: 49,828

    squirrel
    Member

    sounds like you have the answer right there!

    (unless you need to re use the nuts, for some reason)
     
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  4. MrCreosote
    Joined: Jul 23, 2009
    Posts: 283

    MrCreosote
    Member
    from USA

    Good to know, I was definitely scared to heat them that hot.

    What was wrong with the one that couldn't be re-used?

    I don't want to use the torch because I'd have to make all kinds of heat shields to protect 3 plastic covered cables right in the vicinity.

    It sounds like I can "go nuts" with the Bolt Blaster because it will take a lot of heat conduction from the stud to get the nut glowing.

    One thing I liked when "torching off" steel nuts was each time I thermally cycled the nut/stud, lesser and lesser heat would make it into the stud. First time, both orange. After a few times, orange nut and not glowing stud - at this point, the nut is "ripe to harvest."

    Thanks
    Tom
     
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  5. MrCreosote
    Joined: Jul 23, 2009
    Posts: 283

    MrCreosote
    Member
    from USA

    Maybe if lucky! I have pulled nut threads in the distant past. Worst case the nut brazes itself to the stud.

    Problem is that the nuts are high up the side of the engine and the exhaust pipe takes up a lot of the limited space between the frame and oil pan/block. Will probably use an 18" extension to put a socket on the nuts. Any screwup needing close work to fix will be a disaster.

    The studs do not stick out past the nuts so if I would need to run a die over the studs, the exhaust pipe would have to be removed. I don't want to get that involved since that task is for the exhaust shop.

    I'm just trying to eliminate the phone call: "Hey one of your studs broke, what do you want us to do?"
     
  6. Rehpotsirhcj
    Joined: May 7, 2006
    Posts: 1,322

    Rehpotsirhcj
    ALLIANCE MEMBER
    1. Northwest HAMBers

    Maybe I’m missing something…could you save the heat and just split the nuts?
    661AC1C2-AD96-4B05-A1AB-8A9B0338A4D6.jpeg
     
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  7. MrCreosote
    Joined: Jul 23, 2009
    Posts: 283

    MrCreosote
    Member
    from USA

    Impossible to use a tool since no side space. The nuts are basically at the bottom of a small diameter (4") deep (18") hole.
    Further, being a twin pipe, 3-bolt flange, it would be impossible to get such a tool on the "middle" stud.

    Now if someone made a nut splitter that went on axially like a deep well socket, that would work like gangbusters on exhaust pipe flange nuts.
     
  8. MrCreosote
    Joined: Jul 23, 2009
    Posts: 283

    MrCreosote
    Member
    from USA

    Although this does me no good, check out this unique product:

    [​IMG]
     
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  9. brading
    Joined: Sep 9, 2019
    Posts: 438

    brading
    Member

    Above someone has thought out of the box and come up with a simply and effective idea.
     
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  10. There was no threads left in the nut that was not usable. All the studs were in good condition. I did run a thread chaser on the studs though, just to be sure things would go back together nicely.
     
  11. MrCreosote
    Joined: Jul 23, 2009
    Posts: 283

    MrCreosote
    Member
    from USA

    Yes, that is what I remember back in the 70's. I could imagine rust crystals forming and wedging/gripping the brass threads to the point where the brass did have the tensile strength to pull free.

    I think induction heating the stud may work better on brass - hot stud & "cold" brass may yield the brass in tension making it bigger which would be very good for removal.
     
  12. alchemy
    Joined: Sep 27, 2002
    Posts: 17,270

    alchemy
    ALLIANCE MEMBER

    I don't understand heating the stud. You don't want the stud to expand, you want the nut to expand. Try heating the nut and turning it while it's hot.

    If you can get in there with a wire brush to remove any rust, I'd definitely try that first.
     
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  13. Years ago I worked on fleet vehicles that were bad for manifold leaks. Whenever we replaced a manifold we used brass nuts on the studs. If we needed to remove them again, it just took a little heat on the nut – not the stud – and the nuts expanded to the point they could be removed easily.
     
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  14. MrCreosote
    Joined: Jul 23, 2009
    Posts: 283

    MrCreosote
    Member
    from USA

    My limited experience with brass nuts has been on heavily rusted studs for over 10 years. I live in the Rust Belt and road salt creates an especially evil form of rust.

    INDUCTION HEAT STUD: If I can cause the stud to expand while the nut is cold, there will be increased interference between the stud and nut which should 1) break up the rust crystals and 2) hopefully, yield the nut to a larger "diameter" so there is now extra clearance between the nut and stud when cooled down.

    Induction heating is a joy compared to torch when it comes to "collateral damage." I really want to focus on this method.​

    HEAT NUT: The problem with old Studebaker brass nuts appeared to be that the threads would pull out of the heated nut due to it's reduced yield strength due to the heat. I'm not saying it won't work, but Rust Belt + Decades of rusting do not help.

    TORCH ISSUES: There is a lot of stuff in the way that will melt/burn due to flame. This is compounded by the fact that a large nozzle produced the greatest thermal gradients and get the nut to expand before the nut can heat the stud by conduction. Again, there is a lot of stuff in the way that would need to be heat shielded.

    NOTE: Coefficient of Thermal Expansion for yellow brass is 11.3 and steel is 9.4, so just heating nut and stud uniformly should cause rust crystal breaking. But again, flame issues.​
     
  15. BamaMav
    Joined: Jun 19, 2011
    Posts: 5,099

    BamaMav
    Member
    from Berry, AL

    Next time, use never seize. Never had a problem getting one off that had been on a while if I used it when first put on. But if you didn't put them on, never mind, it's not your fault.
     
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  16. MrCreosote
    Joined: Jul 23, 2009
    Posts: 283

    MrCreosote
    Member
    from USA

    YES to NEVER SEEZ! I've used since 1970! I'm pissed, I'm 69 and just ran out of my pint of Nickel. So being the cheap skate I am, I'm trying Saf-T-Exe Nickel rated to 2600*, 8 oz shipped for something like $15. Super cheap, hope it works. Stuff is much "drier" than the NS. Permatex Nickel claim to not migrate, etc. when exposed to heat. I think the NS might slump a little under heat. This STE is so dry, I can't see it slumping. It is also almost black in color while NS was definitely gray/silver. The NS and Permatex was like twice what I paid for the STE.

    When I drop off the truck and parts to the garage that's doing the exhaust fab, I'll include my new STE too. ....but if I successfully get the nuts off, they'll go back on with lots of STE so it might be no biggie if they don't use more.
     
  17. Boneyard51
    Joined: Dec 10, 2017
    Posts: 5,187

    Boneyard51
    Member

    I guess I am the luckiest guy around when it come to brass nuts on the exhaust! I always just put a six point socket on them and they came off, kinda why they use brass nuts there. Some came off in good shape, some stripped the threads, but still came off! Steel nuts…. not so lucky there!






    Bones
     
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  18. Rusty O'Toole
    Joined: Sep 17, 2006
    Posts: 9,608

    Rusty O'Toole
    Member

    When I was in the muffler business years ago if they did not come right off we would melt them off with a torch, wire brush the stud and use new nuts. They are not that expensive.
     
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  19. stuart in mn
    Joined: Nov 22, 2007
    Posts: 1,998

    stuart in mn
    Member

    I would consider brass nuts as expendable items...if the threads strip out when removing them just buy some new replacements, they're cheap. The main thing is unlike steel nuts, since they're brass they won't rust onto the studs.
     
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  20. MrCreosote
    Joined: Jul 23, 2009
    Posts: 283

    MrCreosote
    Member
    from USA

    Melting the brass nuts off: how hard is it to not end up brazing some nut brass to the stud?

    This brings up another question: where to get metric brass nuts? And then how to determine thread size before I take truck off the road to do this job? Looks like I need to purchase some brass nuts to have on hand if needed. Another little logistics issue.

    EDIT, SOLVED: OEM stud 14064-E3000 crosses to a Dorman 03109 Stud and Brass Nut kit M8-1.25 x 38mm Of course it's for a pair and I have 3, so if I save one... O-Reilly's has them in stock so this might be the FINAL purchase of stuff for the job.
     
    Last edited: Sep 30, 2021
  21. Boneyard51 likes this.
  22. Doublepumper
    Joined: Jun 26, 2016
    Posts: 1,080

    Doublepumper
    Member

  23. seb fontana
    Joined: Sep 1, 2005
    Posts: 7,152

    seb fontana
    Member
    from ct

    Penetrating oil and put a wrench to them!!!
     
  24. MrCreosote
    Joined: Jul 23, 2009
    Posts: 283

    MrCreosote
    Member
    from USA

    Found Dorman and a stud kit w/brass nuts for the precise OEM part number of my studs.
    Dorman 03109 - M8-1.25
    upload_2021-10-1_14-14-12.jpeg
     
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  25. 1ton
    Joined: Dec 3, 2010
    Posts: 578

    1ton
    Member

    Don't just try and run them off. Use some penetrant and tighten then loosen, tighten then loosen. Before you know it those nuts will happily squeak themselves right off.
     
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  26. reagen
    Joined: Nov 2, 2005
    Posts: 226

    reagen
    Member

    Have your wife get your nuts off saying for a friend
     
  27. David Gersic
    Joined: Feb 15, 2015
    Posts: 2,435

    David Gersic
    Member
    from DeKalb, IL

    I don’t need this right now, but damn that’s a good idea.
     
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  28. MrCreosote
    Joined: Jul 23, 2009
    Posts: 283

    MrCreosote
    Member
    from USA

    LESSON #1: Induction heating works on BRASS - ".... and any metal that conducts electricity" according to the web.

    WHY do induction cooktops required magnetic pots?

    I can get the brass nuts to Orange/Red which the stud is black. Then the nut heats the stud up until they are both Dull Red.

    The fact that I can get the nut Orange and the stud black suggests the nut is indeed free of the stud. Which should mean the nut can be wrenched off.

    It bothers me that the nut has twice the engagement of the short Dorman stud kits. All that engagement is just what you'd want to break a stud.
     
    Boneyard51 likes this.

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