Cant break free the damn bolts ! help

Alright im replacing the catalystic convertor on my 95 camry 2.2Liter, i cant free the 3 bolts that connect the front pipe to the exaust manifold ( up near the engine ) i use all my strength but cant budge these bolts.. i tried using wd40 to loosen it but its still not budging.. Anyone have any tips to free a stubburn bolt ? does toyota glue the threads or something ? thanks guys

Assuming you do not have an air impact on hand, I would first make sure you're using a 3/4" drive. If not, attach a converting extension to change it to as large a drive as possible. Then, try getting a very long breaker bar to put in place of the ratchet. Sometimes you'd need one more than two feet long. If that still doesn't work, grab a large hammer and tap on the bar at the same time that you're trying to turn it.
Good luck.

Go to Lowe's and get a $15 propane or MAPP gas torch like plumbers use. Heat that sucker cherry red and then get the wrench on it. It will snap the bolt apart like putty and you can put new ones in. If they're that frozen they're worthless anyway.

the problem is the bolts go into the manifold , if i break it off like you said using the mapp gas then how am i supposed to get the reset of the bolt out ?

My friend has a air powered impact wrench. Should i use this ?

If you can't get them off, chances are they're only coming off broken. My apologies... I thought they were bolts from the cat flange to the rest of the exhuast.

You can still use the torch, just heat the nuts only. Then hit it with the impact wrench in short bursts. If that doesn't work, quench it with penetrating oil and reheat. Don't hold the trigger too long or it will twist the bolt off. Avoid using heavy leverage or breaker bars because it WILL twist off before yielding the nut. If all else fails, you can get a nut splitter. Its a cold chisel that will crack the nut.

If you break off the bolt, you have to drill it out and re tap it. Not exceedingly difficult, but time consuming and a lot of time on your back under the car getting metal shavings in your eye.

Even if you're using heavy duty wrenches, the corrosion in the threads (which technically weld the pieces together) may not allow you to remove the bolts without breakage. Try a GOOD penetrating oil (scrap the WD40 and try somethig like 3-in-1) and soak the parts. Let 'em set for a couple of hours then soak 'em again. Give it a day or so to work before taking the wrenches to it. Heating the connection may work, but I'd rely on that only as a last resort.

no the bolt and block threads arent rusted.. i bet toyota put loctite in the threads.

Use mapp gas and get the bolt hot enough until it just about glows. The heat drives the oxygen from the rust, reducing its ability to seize the threads. Also the thermal expansion helps. If its hot enough it will come loose with hand tools.

Whoa MajicRat, Viva Quebec. Where did you get the avitar, my wife is Canadian and would love that on the computer at home?

all done.. i gave up.. didnt have the proper torch.. paid merlins muffler $100.00 to do it for me.. thanks guys for helping..