I am trying to replace my Cat Converter, but the bolts are rusted on pretty bad. I have tried PB blaster and an air impact gun, but all that has done is rounded the bolts. Any ideas on how I can get these off without damaging anything?

 

cut the bolts off. be carefull and take your time

 

For stubborn nuts, I like a torch first, maybe a nut splitter if you can get it in there second, cutting wheel third.

 

go to auto parts store and get a stripped bolt or nut remover socket they work well the new type

 

i find the best way is to cut them off, and then drill the remaining out and put in your own hardware.

 

FTW

 

...X2 Those nut-remover kits are invaluable and handy to have around

 

I just put a new cat on about 6 months ago just cut them with a saws-all on one side and they pop right out

 

I would sawsall it off and just put a piece of straight pipe in the place and weld, that way, some one wont be tempted to walk of with your new like they did mine a month ago, if your truck is 4x4, it is an easy targer for cat theives.

 

Heat it up till its real hot, then douse it in pb blaster or liquid wrench. If it still does not come off, its time to cut it off..

 

Check this out:


https://www.yotatech.com/forums/f116...-rusted-92409/

 

I have the same problem TN! Mine look like two gobs of metal... I think my only option is to cut and tap....

 

IMHO use a grinder - fast and clean if careful. Bolts should then come out easy. Don't waste your time with nut splitters, etc. Sawsall is good but run thru blades fast.

 

Cut the bolts off with an angle grinder and zip disc and hit the rest of the bolts out with a punch and then put in some 3/8'' bolts. They will hold just as good. Whenever I have to cut a bolt off my truck or tap something out it doesn't get replaced with anything metric.

 

^^ that must suck for when you're working on your truck and have to keep metric and SAE wrenches around you

I was able to get my front cat bolts out easy with a stripped not remover, but the back ones I had trouble because the muffler got in the way of hammering the nut remover onto the nut. I ended up pulling the whole exhaust out from the downpipe back and using a cutoff wheel to get the nuts off, then I just kicked the cat and it came loose.

All I had to do then was install a new cat, of course I went with a 2.5" magnaflow cat and muffler followed by a turndown before the axle heheh sounds pretty sexy and not too loud. Get a little gurgle when I let off the gas below 2500rpms.

 

I use 3/8" stainless steel bolts and nuts on my '85 cat. conv. Nice thing is those bolts use a 9/16" wrench and 14mm fits just fine as well. I also apply some metallic anti seize paste on the threads before installing the nuts. Bolts look like new even after 10+ years of use. You could use metric s/s hardware, but realize that those cost a lot more and they will likely have a 17mm head, which means I need to get a different wrench for those than for the other factory 10mm bolts, that have a 14mm head.

 

I keep metric and standard wrenches with me anyways. Socket sets generally come with both. And as 4crawler said 9/16 and 14mm are the same thing and 3/8'' bolts are 9/16. And generally standard bolts are much easier to get. Around here at least.

 

Cut them off with a grinder or Dremel. Mine cat bolts and nuts don't even have distinguishable facets. No way in hell you'd be able to unbolt them normally.

 

the best luck i have ever had on stuff like that is taking a larger generaly a 3/4" nut, crank up the welder and weld the new larger nut to the bolt head, really lay the weld into it, by the time you are done the bolt head and nut should be glowing red hot, almost white hot. grab a impact gun with a good tight fitting sockett and let er' rip.... if that dont work get out the grinder or torch

 

Ohh man am I glad I have oxygen-acetylene torches LOL.. I'd have those bolts out in 2 minute