In a couple of places, the pipe between the catalytic converter and the muffler has rusted out along the welded seam. Patching helps, but I guess I'll need to replace it one day.
Many fasteners on the car can still be undone after 23 years. What about the nuts holding the pipe to the catalytic converter?
Well, I just replaced the exhaust system on my '92 Sentra front to back, with the exception of the converter and the pipe ahead of it.
I dropped the whole system to check it out. I used an air-powered cutoff tool to remove the nuts/bolts even with the flange for the rear pipe. Then I separated the flanges with a small chisel.
I could not get the bolts to unscrew, even after cutting them off flush with the converter flange. Tried tapping them out but no joy. I then cut the nuts off flush with the inner side of the converter flange. Still no luck. I finally drilled them out, and it looked as if they were threaded into the converter flange as well as having nuts on both ends.
It was a lot of work, but it saved me about $150.00, so it was worth it.
I don't know how this applies to your vehicle, I live in the Land of Road Salt. I had no luck unscrewing the nuts on the converter; they just crumbled.
Well, I just replaced the exhaust system on my '92 Sentra front to back, with the exception of the converter and the pipe ahead of it.
I dropped the whole system to check it out. I used an air-powered cutoff tool to remove the nuts/bolts even with the flange for the rear pipe. Then I separated the flanges with a small chisel.
I could not get the bolts to unscrew, even after cutting them off flush with the converter flange. Tried tapping them out but no joy. I then cut the nuts off flush with the inner side of the converter flange. Still no luck. I finally drilled them out, and it looked as if they were threaded into the converter flange as well as having nuts on both ends.
It was a lot of work, but it saved me about $150.00, so it was worth it.
I don't know how this applies to your vehicle, I live in the Land of Road Salt. I had no luck unscrewing the nuts on the converter; they just crumbled.
The heat generated by the cat will virtually guarantee that none of the nuts and bolts on the cat can be removed. You'll have to hacksaw them off. It's best to remove the whole system by undoing the nuts at the exhaust manifold. There is likely a triangular flange there held together with three nuts which typically don't rust out. Once the cat and the pipes on either end of it are removed as a unit, you can saw/ cut/drill at the nuts/bolts. The flanges at either end of the cat on my 87 Sentra had no studs, only holes. So once the old bolts and nuts were cut away, new bolts and nuts could be easily inserted. When you install new nuts and bolts, use liberal amounts of anti-seize compound. It's a good idea to turn the nuts every once in while when you happen to be under the car and reapply anti-seize compound as needed. The heat of the cat will freeze things fairly quickly. Good luck. Al
Thanks to you and Plague Boy. Before your tip, the task intimidated me. I don't have a lift, and if I did, looking up to do that work in a cramped space sounded like a job for a superman with long fingers.
Twelve years ago I fixed holes in the front pipe by welding. I hear it leaking again, but now the screws holding the shield are frozen. Dropping the exhaust system will be a big advantage.
I haven't checked to see if the shop manual recommends that approach. The other day I replaced bearings in the idler pulley for the AC belt. It and the Haynes manual said to loosen the screw by turning clockwise. I'm glad I didn't trust them!
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