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Rusted Exhaust Bolts - Solution?

Posted on 3/3/19 at 11:49 am
Posted by Delacroix22
Member since Aug 2013
4537 posts
Posted on 3/3/19 at 11:49 am
So I was knee deep in some car work yesterday. Putting in a new header which flows all the way back to the catalytic converter.

So I jack up the car after loosening everything in the engine bay I needed to.

The next step was to get under the car and release the splashguard to get to the core components of the exhaust. So I get under there.... and previous owner just did away with the splashguard. OK, great that saves me 20 minutes of unbolting and bolting this plastic back on afterwards. So I went moving forward.

I turned my attention to the bolts for the cat converter and they were rusted as ALL hell. No splashguard these things have been taking the brunt of the undercarriage elements for god knows how long.

Stripped two sockets. Got some impact sockets and a breaker bar, nothing. Even after soaking in WD-40.

So I need a suggestion....

1. Take it to a muffler shop and offer them some $ to just loosen the bolts I need to remove. Just loosen them, but keep them on. So I can drive it home and finish the install myself. The only issue I have is what if they have to cut off the bolts and they don't have adequate replacements?

2. Take it to an Acura dealership and offer them the same deal, only advantage I can see to this is that if they have to cut the bolts they most likely will have correct replacements if it comes to that? Only downside I can see is them not having tools to cut the bolts if it needs to be done.

3. Get a blowtorch, rent an impact wrench, try a bunch of home remedies again and hope that it works?

These things are ridiculously stuck I'm surprised a socket didn't explode. I've seen multiple people say that an impact wrench can loosen ANYTHING like it's a joke... I want to believe that.
Posted by The Mick
Member since Oct 2010
45189 posts
Posted on 3/3/19 at 11:51 am to
Spray blaster penetrating catalyst on them wait couple hours repeat.
This post was edited on 3/3/19 at 11:54 am
Posted by choppadocta
Louisiana
Member since May 2014
2590 posts
Posted on 3/3/19 at 11:53 am to
Kroil or pb blaster..let them soak overnight. Wd40 is not a penetrating oil. Heat the area around the bolt not the bolt itself should help.
This post was edited on 3/3/19 at 11:55 am
Posted by weadjust
Member since Aug 2012
15814 posts
Posted on 3/3/19 at 11:53 am to
Posted by LEASTBAY
Member since Aug 2007
16662 posts
Posted on 3/3/19 at 11:53 am to
I would start locating a new set of bolts asap. No matter what happens you might destroy them. Probably gonna need a torch to get them red hot before they will turn. These exhaust bolts are the worst. Heads might eventually break off and you will need vice grips to get the rest out.
Posted by redstick13
Lower Saxony
Member since Feb 2007
41357 posts
Posted on 3/3/19 at 11:59 am to
Buff them off if you can reach them then hit them with some high grade penetrating oil and let them soak overnight. Hit them with heat as the last option.
This post was edited on 3/3/19 at 12:07 pm
Posted by TSLG
Member since Mar 2014
6724 posts
Posted on 3/3/19 at 12:04 pm to
I went to get you a video, but I found this post on a different site. It's pretty spot on, but I think that I'm more of a fan of heat than this guy.

Heat that fricker up with a hot torch.

Honestly, id just take it to an exhaust shop and let them do the hard part.

quote:

My general rule for exhaust bolts/nuts is to order new ones with the part you are replacing, knowing full well that there is a good chance you'll destroy the ones you are removing. Better to be prepared ahead of time than to be stuck waiting for new parts from another country after you've disassembled everything. Personally, I have a rule of ordering every bolt and nut that is attached to the exhaust member I'll be replacing. Even if there isn't much rust, I never know when a bolt will snap.

First task is to let the exhaust completely cool. It's possible that the parts are made of different types of metal which expand and contract at different rates.

Now, how to get the rusted bolts off:

Use an impact wrench. Sometimes the vibration and hammering action works better to "knock" a bolt loose, compared to wrench/breaker bar. In my experience, this is the first tool of choice for 95% of techs working on an exhaust system.
Use a big breaker bar. 2 ft is okay, 4 ft is more like it. Use high quality, name brand tools that won't flex or shatter on you (or at least give you free replacements when they do shatter). The flexing is important. If the cheap breaker bar is flexing instead of transferring the full torque, you may as well not have it.
Sometimes there is just too much material rusted off of the bolt for either of the above to work. Or one of the above techniques may round out the bolt before it comes out. In this case, the bolt needs to be destroyed so you can move on with life. Some options are:

Die grinder with appropriate wheel.
Hacksaw / airsaw.
Air hammer with chisel bit.
In extreme cases, torch.
As always, use high temperature anti-seize when putting in the new bolts. They will go in easier, and the next person down the road will thank you.

Safety Note: All of the above methods assume you know the safety procedures for the tool. Of particular importance is having the vehicle properly raised on the car lift. Some of these methods involve violently pulling stuff around, which will cause the car to move.
Posted by arcalades
USA
Member since Feb 2014
19276 posts
Posted on 3/3/19 at 12:24 pm to
quote:

pb blaster.
this. At least 24 hours. 48's not a bad idea. Many people give it a week, spray every couple days. There are many good youtube videos on this.
Posted by arcalades
USA
Member since Feb 2014
19276 posts
Posted on 3/3/19 at 12:29 pm to
quote:

try a bunch of home remedies again and hope that it works?
this if you have the time and energy and/or don't want to give your money away.
quote:

2. Take it to an Acura dealership and offer them the same deal, only advantage I can see to this is that if they have to cut the bolts they most likely will have correct replacements if it comes to that? Only downside I can see is them not having tools to cut the bolts if it needs to be done.

if they don't have the tools or time, they'll outsource to someone in the area. Most people prob don't know how much car repair work actually gets outsourced.
Posted by Shepherd
Member since Nov 2009
3099 posts
Posted on 3/3/19 at 12:32 pm to
Do not take a torch under that car. Sawzall or diamond blade/grinder cut the bolts.
Posted by danfraz
San Antonio TX
Member since Apr 2008
24550 posts
Posted on 3/3/19 at 12:36 pm to
Posted by ChocoLab
Member since Aug 2017
148 posts
Posted on 3/3/19 at 12:49 pm to
Kroil, heat, Kroil, impact
Posted by weadjust
Member since Aug 2012
15814 posts
Posted on 3/3/19 at 12:54 pm to
You're going to have to replace the nuts/bolt no matter how you get them off
Posted by TSLG
Member since Mar 2014
6724 posts
Posted on 3/3/19 at 1:25 pm to
quote:

Kroil, heat, Kroil, impact


This is what I'd start with.
Posted by Redbone
between St. Amant and Port Vincent
Member since Sep 2012
20738 posts
Posted on 3/3/19 at 1:31 pm to
IF you get something that will grip head of bolt (Probably too late for that) You are going to break the bolt(s).

As others have said, no WD40. Get something that is meant for that. It probably isn't going to get to the bolt threads.

Heat as they say or cut the bolt heads off and hope you can get the remaining stud out after the manifold is off.

Be prepared to to remove head. This will probably not end well.
Posted by Eli Goldfinger
Member since Sep 2016
32785 posts
Posted on 3/3/19 at 1:40 pm to
Sawzall and/or grinder
Posted by weadjust
Member since Aug 2012
15814 posts
Posted on 3/3/19 at 1:42 pm to
quote:

Be prepared to to remove head. This will probably not end well.


The catalytic converter bolts are the problem. OP already said he got everything loose in the engine compartment.
Posted by CHEDBALLZ
South Central LA
Member since Dec 2009
23341 posts
Posted on 3/3/19 at 1:46 pm to
Go to harbor freight and buy you an impact wrench.
Posted by LEASTBAY
Member since Aug 2007
16662 posts
Posted on 3/3/19 at 1:49 pm to
Impact is gonna break the bolts off. And least some of them.
Posted by Delacroix22
Member since Aug 2013
4537 posts
Posted on 3/3/19 at 1:51 pm to
quote:

Be prepared to to remove head. This will probably not end well.


quote:

The catalytic converter bolts are the problem. OP already said he got everything loose in the engine compartment.


The head? As in the header?

Yes that is coming off, I loosened all that up before moving under the car. I'm putting in a new header that is a seamless one piece from the header all the way to the catalytic converter. There are some spring bolts that I didn't even mess with after I gave up, but that assembly will be in the garbage afterwards because like I said the new part is seamless one piece.
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