What did you do for exhaust replacement?

[tedwardd]

I attempted to replace a bad O2 sensor today and sheared one of the mounting studs clean off the pipe. I am attempting to work on the other one more gently but TBH I was using a 1/4” socket to begin wi5 and barely put any toque on the one that broke so I’m not sure I can do too much to the other one before it too breaks. I’ve been soaking it every few hours with PB blaster and taking a torch to it but it’s not budged yet.

This leads me to the meat of my question. What would you do in this situation? My instinct is to take it to a shop, have them cut them off and weld on new studs. But I’m not sure if the labor required would end costing more than a new exhaust all together. That lead me in to thinking if doing so would be a good opportunity to have the sensors relocated to a spot that is a little less exposed to the elements and easier to reach for future me… and, well… then I thought I should probably poll the group to get input before I got carried away or reinvented the wheel.

So, in this case the exhaust is stock and all bolts and clamps on it are heavily HEAVILY corroded and unlikely to loosen without, at least a good fight. There are no leaks so it’s definitely useable but there’s no way to non-destructively pull the sensors or do any other service to it. Would you replace it with an aftermarket kit, have a shop replace the pipes or salvage the stock system?

 

[jpoole]

I'd have to see the system and would feel my way forward through the options depending on how things went but I would start by putting effort into retaining the stock system if it is solid overall.

My 330k '97 is running the stock exhaust system and when I got it 100k and 10+ years ago I ran into issues like you describe when replacing the O2 sensors, the insulator/mounts and replacing the seal/gasket between the two cats, etc. I was really on the fence regarding full replacement but had time to tinker and once I had the O2 sensors replaced the rest fell into place pretty easily. The system has been trouble free over the last decade/100k miles and shows no sign of additional wear so it seems at this point that fixing it was the right approach. The stock system is made of good stuff and many non-stock replacement parts are not going to last nearly as long, especially in rust causing conditions.

Keeping the stock system could be a good excuse to buy a welder, if you don't already have one, to help with extracting broken off studs or patching up a few spots. You can get a welder for far less than a new, stock exhaust system and it may make keeping the stock system in good shape a lot easier. I think I used my welder to get one of the broken off O2 studs out and to patch a spot on the muffler which saved me needing to pay a shop to do these little tasks. I use one of the Harbor Freight Titanium 125 flux core welders and get great results out of it as an amateur. I've used other processes / machines and there are trade-offs but for my typically small, one-off tasks I like the form factor and simplicity of the 125 and don't mind the clean up when done.

 

[98 SNAKE EATER]

If you snap the other one, get a new bung and weld it on top of the old one

This would be easier than trying to pull a corroded pipe just to fix a stud

 

[Kernal]

AFAIK the O2 sensors should be sitting at a specific depth to get a good reading (tip in the exhaust gas stream) so the old bung might need to be removed before welding on a new bung with studs??

The original studs were M8x1.25 but as mentioned Toyota doesn’t sell them separately but any generic M8 x 1.25 x ~30mm threaded stud should work.

 

[tedwardd]

I'd have to see the system and would feel my way forward through the options depending on how things went but I would start by putting effort into retaining the stock system if it is solid overall.

My 330k '97 is running the stock exhaust system and when I got it 100k and 10+ years ago I ran into issues like you describe when replacing the O2 sensors, the insulator/mounts and replacing the seal/gasket between the two cats, etc. I was really on the fence regarding full replacement but had time to tinker and once I had the O2 sensors replaced the rest fell into place pretty easily. The system has been trouble free over the last decade/100k miles and shows no sign of additional wear so it seems at this point that fixing it was the right approach. The stock system is made of good stuff and many non-stock replacement parts are not going to last nearly as long, especially in rust causing conditions.

Keeping the stock system could be a good excuse to buy a welder, if you don't already have one, to help with extracting broken off studs or patching up a few spots. You can get a welder for far less than a new, stock exhaust system and it may make keeping the stock system in good shape a lot easier. I think I used my welder to get one of the broken off O2 studs out and to patch a spot on the muffler which saved me needing to pay a shop to do these little tasks. I use one of the Harbor Freight Titanium 125 flux core welders and get great results out of it as an amateur. I've used other processes / machines and there are trade-offs but for my typically small, one-off tasks I like the form factor and simplicity of the 125 and don't mind the clean up when done.

Thanks for the suggestion and insight! One of the first things I realized when I got this truck is that a basic welder, and learning to use it, are going to be invaluable in repairing and maintaining it. I've already encountered no fewer than 10 situations over the last week where, if I'd had a welder, I could have done a "proper" fix or made the process of doing whatever it was I was doing a lot easier. From the looks of it, the bung has already been replaced once (just judging by the quality of the weld on one pipe vs. the other) or at least repaired at one point and, you're right, a basic entry-level welder at Harbor Freight, including a mask and gloves would run me probably $100-200 less than having a shop do the work considering all the labor that would be involved.

I guess the good news in all this is that, in the process of heating up the remaining stud with the MAPP torch to try and break it free I somehow "fixed" the existing O2 sensor so it's not throwing a code anymore. So, for now, I'm going to get a hose clamp to try and hold down the one bolt-less side of the flange to reduce some of the sound from the small exhaust leak that I now have and live with it. I've already dumped enough money in to this truck for one month.

 

[Kernal]

Might be worth asking a few Muffler shops (small independant shop) if they can repair/replace the bung, used to be they'd charge $20-30, but I guess these day's they might want a lot more.