Y-pipe leak

[nola mike]

Failing inspection because of a leak between the y-pipe and cat. A couple of questions:
1) Looks like 3 bolts holding everything together. Ain't no way those are coming out. I think I have enough room to get a sawzall in there at the joint. Yes? Other suggestions? Do I need to unbolt the Y-pipe to get at the flange bolts?
2) Can't tell whether those are through bolts or studs on the cat? If studs, I guess I'll have to remove the cat and drill out the studs and replace with bolts?

 

[Dirtman]

The inspections in VA continue to amaze me... Why does the state give a crap if an exhaust flange is leaking?

Anyway don't entirely give up on unbolting just yet, yea they will probably break, snap, whatever but you'd be amazed at the things I've been able to get off with homemade penetrating fluid (transmission fluid and acetone mixed 50/50) and a home depot propane torch. If you have a few days, spray those bolts down with the penetrating fluid every night (after letting the engine cool!) For a few days. Then on removal day wipe any excess oil off and carefully heat each bolt with a torch. They don't even need to be close to red hot. Then give them a try, you might be surprised. Waaay less work than cutting, hacking and drilling if you have a little patience. Worst case scenario you snap them all off but that just saves time trying to cut them off!

 

[nola mike]

Yeah, I can't even get a good grip on the nuts. They're going to round off. Can't even tell if they're 1/2" or 9/16".

 

[adsm08]

The inspections in VA continue to amaze me... Why does the state give a crap if an exhaust flange is leaking?

Exhaust leaks are a common point of failure among many of the more involved state safety checks.

Even post-cat the exhaust isn't exactly something we can breathe. Exhaust leaks under the body can allow exhaust gas to build up inside the passenger cabin at a stop. This can be dangerous to the driver, passengers, and people in other cars, since one of the first symptoms of CO2 poisoning is getting very sleepy.

I am not an expert in the matter but my wife, who is pretty smart, keeps telling me that I should not sleep and drive at the same time.

 

[nola mike]

I don't have a huge problem with this as a safety/emissions fail. It's all the other BS. They initially told me it was the post-cat flange that was leaking (it was). I fixed it, then they tell me it's this one. I'm kind of surprised that I haven't thrown a code given the size of the leak (looks like the lower part of the gasket is gone). Not looking forward to this repair, but the shop wants $250+...

 

[nola mike]

OK, so that was a GIANT pita to separate the cat from the y-pipe. That 20 year old hardware wasn't budging. I ended up cutting the bolts (studs?) between the flanges. First 2 were no problem. Last one took me more than 2 hours to try to get a sawzall in there. Even then, the flanges were so rusted together that it took me forever and a few blades to get through it. Very difficult access. Also tried dremel, oscillating tool, hacksaw, cutoff wheel. Anyway, I now have it apart and have pretty good access. One of the nuts came off with the cut part of the bolt. The others are still attached to the Y-pipe. I can't tell if there are bolts or studs on the cat side. Either way, frozen in there and ruined. Options:

1. Try to get the rest of the nuts/bolts out. Doubt this is gonna work.
2. Cut everything flush, and redrill holes.
3. Use a flange repair kit like this. This is my favorite option, will certainly be the quickest.

Anyone ever tried this? Better ideas?

 

[nola mike]

This is getting waaay too involved. I removed the cat. I was able to pound out the nuts from the y-pipe from the back side. Now I'm trying to remove whatever the hell is filling the holes on the cat flange. I guess they're studs? It's hardened something, competely unable to drill through it. Are they pressed in studs? That's my assumption, but would love to know what I'm dealing with. I can't pound them out. I'm going to HF tomorrow and buy a hydraulic press and see if I can press them out. I guess if not, I'm going to throw in the towel and bring it to a machine shop. Can someone clarify what exactly these things are?

 

[adsm08]

Should be a splined stud that goes into the flange. A liberal application of heat before pounding should help.

 

[nola mike]

Should be a splined stud that goes into the flange. A liberal application of heat before pounding should help.

Thanks. I've been looking for an excuse for years to buy a hydraulic press, so will try that tomorrow. Can't believe how quickly I went through drill bits with no luck. Shit must be made of kryptonite infused diamonds.

 

[adsm08]

I agree that any excuse to buy a press is a good one. Just remember, go big or go home. Get the 20T unit.

You can't drill through it because the metal gets hardened after many many heat cycles. That is how you harden metal, heat it up, cool it down, heat it up, cool it down.

I would still make use of a liberal application of heat.

 

[BlackBII]

I was able to get those studs out with a quality c clamp type ball joint press.

 

[adsm08]

I was able to get those studs out with a quality c clamp type ball joint press.

I usually manage this job with my hand-held air chisel. That's not really the point.

The point is "If you are buying a press, get the biggest one you can. You will probably regret it at some point if you don't.".

 

[nola mike]

Well, got the 12T (I have really limited space). The cat was *just* too big to fit in there. Don't know if the 20T would have been better. Ball joint press would have been good to try, and I realized I have a hydraulic log splitter that probably would have worked. Anyway, I ran out of time and got frustrated. Brought it to a machine shop, got them out for $45. Pretty pissed about it, but whatever. Then the amazon gasket (mahle) had the wrong bolt hole pattern. Went to FLAPs, they didn't have it in stock, drove to another one 5 miles away...and THAT one didn't fit. It was a walker. Correct hole pattern, but opening around the flange was way too big. Decided to put on the mahle gasket before I killed someone. Tied it up with some SS bolts. None of them went through the holes on the gasket, but it sealed up fine. Longest 1 hour project ever.

 

[adsm08]

Well, got the 12T (I have really limited space). The cat was *just* too big to fit in there. Don't know if the 20T would have been better.

20T would have been better. One of my friends has the HF 12T and I have the 20.

An Explorer rear knuckle is a tight fit in his press all the way around. I spent the $110 on the 20T pneumatic/hydraulic ram because I got tired of spending an hour working the jack out on the highest setting for the bar.