I have an 01 4runner that just crossed 300k. Other than the exhaust leak the truck runs great. I now have an exhaust leak at the bottom of the collection tubes coming off the manifold. The leak is right at the flange between the manifold pipes and the flange which connects to the rest of the exhaust system.Seems like there is no longer a gasket between the flanges.
1). Question How hard is it to remove the bolts holding the two flanges together? Pretty rusted
2). What type and how thick of gasket material should I put between the flanges.
Thanks very much. Greatly appreciated
Ive tried to upload a picture to help everyone out but no. luck so far
Thanks again

Get some PB blaster to help with the bolts. Spray some on and leave it for a day and it'll make your life tons easier.

I would recommend just buying a new gasket.

Thanks the bolts look shot. I have a feeling it will be sawzall time to get them off.

As fluffeh said above, you can use pb blaster, or wd40 to loosen those bolts up.

Sorry to dig up an old post but I've got the same problem. Definitely can feel the air whoosing out right above the area where the flanges are mated. I think the rust was holding it together until I took some train tracks too fast. I think this may actually be a common problem with the older/rustier 3rd gens.

Once I get the repair complete, I'll post back with part numbers and my suggetions for completing the repair. Just giving you guys a heads up.

If you end up getting a new muffler, ill take your old one!! Thats if its stock in still on good condition.

You know, funny thing is I might be getting a new exhaust. The existing one is pretty beat up though. No less than a few hours after posting my above message, i had a guy plow into the back of my runner. My lift gate, tow hitch and bumper are toast. I'm actually wondering if they'll total it.

Ah man! Sorry to hear that! Take advantage of this opportunity though! Get a new rear bumper like @ChildrenOfBodom did. Show the guy that it's less to get an armour bumper, than it is OEM. Unless you already talked to your insurance company...

Just to update this post, this is the gasket in case people have an exhaust leak at the flange from the cat (catalytic converter) to the pipe leading to the muffler:

Autozone - Fel Pro Exhaust Flange Gasket PN#61039 - $3.99

When I searched the part number on this site, I also came across an informative post on replacing the catalytic converter that also covered replacing this gasket as well as the fasteners: Cat Stolen - R+R - Cheaper

I have a '98 and the install was as simple as 1) remove the two bolts, nuts, and washers holding the flanges together - a 17mm box end wrench and 17mm socket wrench (or breaker bar and 17mm socket) are required 2) I cleaned the mating surfaces with brake cleaner and wiped them down 3) install the gasket around the lip portion of the pipe that leads to the muffler 4) carefully bolt the flanges back together by evenly tightening the bolts in order for the gasket to crush evenly.

Thanks again to everyone on this site for their wealth of information.