Catalytic Converter...

[George B]

George, earlier I had read about heating that nut up with a propane torch so I bought one at Lowes a few hours ago. I got up there and heated one nut up until it was slightly glowing red and tried again and it will not move. I've been trying to be very careful but I can feel the corners of that nut rounding over. I've tried every 15mm socket I have and they're all the same. They all just feel slightly too large because of the play. It was like that before I even started but worse now. I'm thinking I might need to use a nut splitter to get it off now...uggg. Thanks for the reply!

which ones you working on? If its the manifold studs You will need to get that nut cherry red to almost orange. The torch I shared will help you concentrate heat on the nut first leaving the stud slightly cooler. Use a 6 point socket.

 

[George B]

get it glowing bright, as hot as your torch can get it, or stop when you see it deform, melt or bubble, and hit it with the impact. run a rethreader on the studs, and get new nuts to go back on
It is originally a 15. if it’s wilted down from rust enough, I’ve used a 9/16 on a rare few.

Yes, a 9/16 might work. I would still be gun shy of an impact tho. I would be afraid of twisting it off as I have several times. Then you need to replace the stud.

 

[wjburken]

Thank you M. I got it as red as I could. Those nuts weren't that rusty either so I don't know why a 15mm didn't fight tight on them. Maybe my Craftsmen sockets are larger than normal or something.

Are you using a 12pt or a 6pt socket. I like the 6pt when I need to torque on stuff. Get a little more bite on the hex.

 

[mijohnst]

which ones you working on? If its the manifold studs You will need to get that nut cherry red to almost orange. The torch I shared will help you concentrate heat on the nut first leaving the stud slightly cooler. Use a 6 point socket.

Well, that's what I probably did wrong. It as red, but not glowing red. I'll go by Home Depot tomorrow and pick one of those up. Thank you for the suggestion. Now that's is stripped though I guess I'll try to get some vice grips on it. Thankfully it's all easy to get to. I'm going to pull the front driveshaft off tomorrow and I'll have full access to it.

I bought a 6-point socket while I was at Lowes but it was just as lose (maybe even a little more) than my other sockets. Maybe I need to try another brand.

 

[ks03]

Yes, a 9/16 might work. I would still be gun shy of an impact tho. I would be afraid of twisting it off as I have several times. Then you need to replace the stud.

Where I eventually landed was, give em a quick bump, if they don’t go pretty easy, jump up to significant heat, and run em out in 1 shot with an impact. Seems like I’m more likely to have trouble if I’m reheating. Also wondered if I put more of a side load on it if I try by hand

 

[mijohnst]

I am surely going to heat the next five up, but now I have to deal with this one that's stripped out. I really appreciate all the advice from you guys. Here's what I'm dealing with now.

 

[George B]

You could try to see if a 9/16 fits on it. On occasion I have been able to pound one onto a nut like that. Just use one that you don’t mind damaging. Have it orange hot first and work fast.

 

[drakon543]

ya ive gotten those nuts off intact and its looked worse than that. half joking but you are going the ring way right? counterclockwise. might be able to get a nut/stud extractor on there. might be easier than getting a nut splitter on it. definitely dont use those multi point sockets when your tinkering with your own vehicle. handful of vehicle bolts are somewhat vehicle specific and if you bust them up you could end up waiting around just for a bolt to finish a project.

 

[OR VietVet]

If you break a stud you can just drill it out and use a through bolt and nut.

In the pic the end of the stud has a 6 point on it so you can use a socket to hold it while you use a 6 point wrench on the nut.

 

[mijohnst]

If you break a stud you can just drill it out and use a through bolt and nut.

In the pic the end of the stud has a 6 point on it so you can use a socket to hold it while you use a 6 point wrench on the nut.

I'm really hoping I can get those off without breaking them. I'm going to try at least. I've ordered a set of bolt/nut extractors. The strange thing about buying those is that most kits skip the 15mm. I don't get that. Every kit has a 14mm and 16mm but they skip right over it.

The plan is to get that thing cherry red, put on the nut extractor and turn counterclockwise. (I have second-guessed myself about a thousand times on the direction.) lol

 

[OR VietVet]

You may have to take a 14mm 6 sided socket and pound it on the nut. If I was you I would use an air or electric impact and you can "burp" it a little as you tighten and then reverse it and "burp" it a bit at a time to break it loose. You will have to push ******* to that nut since it is getting rounded.

 

[mijohnst]

Thank you, Ron. It's raining here all day so I guess it'll have to wait until Thursday when it stops. Great ideas!

 

[George B]

for reference 9/16 is 14.27 mm if you want to drive a socket larger than 14 mm on it.

 

[mijohnst]

for reference 9/16 is 14.27 mm if you want to drive a socket larger than 14 mm on it.

Good point. I'm going to try out that nut extractor that I ordered on Amazon and hope that does it. If it doesn't, my next option is a 9/16 socket. Thanks for the info!

 

[OR VietVet]

It would be best to use an impact 6 point socket. They don't flex and give as much and if you "burp" it with an impact it will rattle the nut and threads better when loosening.

 

[rockola1971]

I would have hit them with a grinder already and installed new bolt/nuts. Time is short and bolts/nuts are cheap.

 

[Wylie_Tahoe]

I removed the exhaust on mine (300K mls) just last nov. Those nuts didnt budge first go. Soaked my nuts for a few days with PB, then hit with heat as I cranked each one. They all popped loose and threaded right off.

I prefer to use a pull bar over impact here. I want to feel whats going on with the nut. If the socket start to round, I can feel and stop. You can even feel the stud twisting.

Coat with anit-seize when reinstalling.

 

[JonnyTahoe]

I would have hit them with a grinder already and installed new bolt/nuts. Time is short and bolts/nuts are cheap.

Big time frustration. Had a situation like this with a mid pipe connection flange bolt. Took it to a local muffler shop and had them get it off.

 

[mijohnst]

I removed the exhaust on mine (300K mls) just last nov. Those nuts didnt budge first go. Soaked my nuts for a few days with PB, then hit with heat as I cranked each one. They all popped loose and threaded right off.

I prefer to use a pull bar over impact here. I want to feel whats going on with the nut. If the socket start to round, I can feel and stop. You can even feel the stud twisting.

Coat with anit-seize when reinstalling.

Well, tonight is the night. I've been soaking each one with the penetrating oil Ron recommended twice a day for the past week. I bought that small oxy-acetylene kit that George recommended to heat those bolts up. One at a time I got them all cherry red and then cooled them off quickly with a spray bottle. Then they turned right off! Thank God I don't have to worry about broken studs to drill out. Thank you all for the help again!

I'm going to clean those stud threads up with my rethreader before I put the new one on. Thanks for reminding me about the anti-seise John. Hopefully, I'll never have to do this again. Does anyone have the torque spec I need to put the exhaust manifold back to the pipe flange? I read somewhere 35lb but that doesn't sound right.

I also want to add to anyone doing this with a 4x4... taking out my front drive shave gave me a lot more room to work with on the left side. Might as well change out those factory u-joins while it's up anyway.

 

[George B]

Well, tonight is the night. I've been soaking each one with the penetrating oil Ron recommended twice a day for the past week. I bought that small oxy-acetylene kit that George recommended to heat those bolts up. One at a time I got them all cherry red and then cooled them off quickly with a spray bottle. Then they turned right off! Thank God I don't have to worry about broken studs to drill out. Thank you all for the help again!

I'm going to clean those stud threads up with my rethreader before I put the new one on. Thanks for reminding me about the anti-seise John. Hopefully, I'll never have to do this again. Does anyone have the torque spec I need to put the exhaust manifold back to the pipe flange? I read somewhere 35lb but that doesn't sound right.

I also want to add to anyone doing this with a 4x4... taking out my front drive shave gave me a lot more room to work with on the left side. Might as well change out those factory u-joins while it's up anyway.

This is good news! I would recommend you buy some new high quality nuts and use one of them to chase the threads rather than something that will remove material. Use lots of oil! With anti-seize it will be hard to get a good torque reading so I wouldn’t go too tight. 35 is probably ok on that. You can always snug em again after a few heat cycles.