I decided to do a good deed and change the rusted center pipe on my inlaws 88 Accord. Of course this is turning into a bigger job than expexted. I finally got pipe out but cutting and grinding the bolts that held the pipe to the cat convertor. I thought I could just push the bolts out, but apparently not. Any tips on getting these bolts out?
---------------- Alex
the bolts are captive & come with the pipe. oem pipe anyway. if you can seperate the pipe from the converter, you should be in business for replacement.
The bolts between converter and center pipe (Pipe B) are actually separate, and are called "converter bolts". On my 94 Civic these are specialty bolts (not cheap, same for the 88 Accord) that have a thin, flat head and "ridged" spine designed to grip in the holes in the converter and help prevent the bolt from turning as you apply the nut.
I tried to get mine out but found that the rust was more than I could handle with my equipment. Mechanic charged me $75 to do it. Maybe try heat and hammering them out with a punch from the Pipe B side? Just be careful not to pound so hard that you damage either the cat or Pipe A, both of which cost a lot. Might be better to drill them out.
I used a 5" angle grinder (wear a full cover face mask when doing this) and cut them off both ends of the cat - both nut end and bolt end. Removed the pipes and cat and drilled out the bolts in the cat and replaced them with new bolts. Be careful with the cat sensor - it will disconnect.
I got the pipe off after much effort. Unfortunately it looks like the bolts are captive on the cat converter, which I am not changing. I guess I will be grinding and drilling. I hope there is enough room to put in bolts once I grind them off. Thanks.
------------------ Alex
Thanks for the tip. I tried pounding on the bolts with a hammer, not a big one, and they bolts would not budge. I tried drilling them out, but my drill bits were not up to the task. I'm going to buy a couple of decent bits before I try again this weekend. Since I am going to drill them out, I'm not going to bother with the special bolts.
---------------- Alex
ordinary bolts will soften & creep at high temperature. and the exit of the cat is /very/ high temperature!
What is the difference between ordinary bolts and the ones you refer to, Jim?
the OEM bolts are splined to stay snug in the hole. right?
Ahh, is THAT what it's called. Yes, they are splined. The shop that got the old ones out for me was apparently able to get them out without making the holes too big to grip the spline--I'd be careful about that if you're drilling them out. Pretty heavy-duty little suckers, too--though short, they weigh several ounces at least (3 of 'em, anyway). No wonder they were some $7 each.
should be an alloy better able to take the temp. if you go to extremes, you use cast components too.
This is what I ended up doing. The grinder went right through the bolts. I then drilled out what was left. One important piece of advice I would pass along to anyone doing this job is to pull the exhaust system out of the car. The bolts that hold the exhaust to the header pipe came off very easily. Once I had the pipe/cat conv. out it was much easier to to the work. I used bolts I got at the autoparts store that were marked 8.8. I'll see if they really do succumb to the hear from the cat conv and fall apart.
------------- Alex
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