New Exhaust Hitting Front Yoke of Front Drive Shaft

DC0046

DC0046

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Feb 23, 2016
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Oklahoma City, OK
Mini cats were shot so ordered an exhaust system off of eBay. Paid a local shop to Install it and now the front yoke of the drive shaft is hitting the rear cat y pipe. Have been back three times and installer heats up pipe to collapse it. Still hit on hard front in dip. Installer was paid but clearly doesn’t want to deal with this. I figured someone on here has had a similar issue and thought I would ask for advice. I have a o e inch MML which tilts the engine a bit and may be contributing to the issue. How much can the y pipe be collapsed before causing a problem? Thanks.
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That's not normal. Looks like you must have bought a very poorly made aftermarket part.

I replaced mine with the Eastern Catalytic ones and didn't have this issue at all.

You could collapse that area more without issue, but I wouldn't be banging on it like it looks like someone was doing. That not only looks bad, but it's probably weakened it structurally.
 
Chris said:
That's not normal. Looks like you must have bought a very poorly made aftermarket part.

I replaced mine with the Eastern Catalytic ones and didn't have this issue at all.

You could collapse that area more without issue, but I wouldn't be banging on it like it looks like someone was doing. That not only looks bad, but it's probably weakened it structurally.
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Thanks. The installer heated it up and used channel locks on it.
 
I had the exact problem with aftermarket cats. I beat the exhaust up pretty badly and, I think, that beating caused the cats to fail again. Lesson learned. I bought a slightly more expensive set, and the bends were much better as fars moving the exhaust up and away from the front driveshaft. The 'better' exhaust was a Pacesetter, also purchased from Ebay. I don't recall the first one, but I believe I picked it up from Rock Auto. You can see in the pic that the new set up (front) th rear pipe runs upward, away from the driveshaft.
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So, yeah, I am afraid you are probably just dealing with same issue I had. I'm not sure what else the muffler guy can do with it aside from replacing the section of pipe, which might get cost prohibitive. Good luck. Like I said, with mine, it wasn't long before the catalyst cracked again and started creating problems, so I never had much opportunity to come up with a work around. -T.
 
Had the same issue with Bosal brand cats. You can go to an exhaust shop and have them cut off the bends and re-do it. Thats the path I took with mine.
 
I'm sure I'm going to freak out some tree hugger but here it goes...
Back in the day when CATS went bad we took them off, took a steel pipe and sledge hammer and hollowed them out and then put them back on, voila... factory "CATS".
I recall I still passed emissions with it that way. Oh wait... the shop that did inspections didn't care too much about that. Ahhhhh... the good ole days.
 
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My factory set-up had the same problem...It has to do with how you bias the assembly when the 4 bolts that connect the downpipe assembly to the manifold are tightened. I loosened mine up and pushed the assembly away...HARD. The whole assembly will kinda rotate away from the DS. Tighened the clamps back up and I haven't heard it clatter since.
 
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Mike_H said:
My factory set-up had the same problem...It has to do with how you bias the assembly when the 4 bolts that connect the downpipe assembly to the manifold. I loosened mine up and pushed the assembly away...HARD. The whole assembly will kinda rotate away from the DS. Tighened the clamps back up and I haven't heard it clatter since.
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I did the same but the heat shields on the cats are pushed to within 1/4 inch of the engine block. I ended up grinding some of the corners off the yoke to give just a little more clearance. At first glance you would think that my axle is slightly biased towards the passenger side, hence the clearance problem. But in fact it is biased towards the drivers side by maybe 1/4 inch. The Mopar cats I replaced did not have this problem. I think it is just a manufacturing tolerance problem.
 
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thanks for the replies. I actually considered beating what was left of the guts out of the pre cats but was concerned about throwing codes. The front cat was completely void of any ceramic and the back one had two chunks just floating around. Had the bend cut out yesterday and pieced back together. It clears now. Hopefully any articulation off road will not cause it to hit. I will post pictures of the fix later today. One thing I have noticed is the jeep seems to run much better (quicker). Not sure the back pressure of the new cats makes a difference or the additional heat they create makes for a better fuel mixture via the O2 sensors. Much smarter folks on here than me on the subject.
 
Mike_H said:
My factory set-up had the same problem...It has to do with how you bias the assembly when the 4 bolts that connect the downpipe assembly to the manifold are tightened. I loosened mine up and pushed the assembly away...HARD. The whole assembly will kinda rotate away from the DS. Tighened the clamps back up and I haven't heard it clatter since.
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Thank you. We see it all the time. Bolts at the manifold get loose, exhaust sags down on the passenger side, swings the down pipe into the path of the pinion yoke. We loosen the bolts, jack up the passenger side to swing the down pipes over tighter to the oil pan and tighten it back up.
 
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I had the same problem last spring when I had a shop replace the front cats. They claimed they tried three different brands and all had the same problem. They ended up cutting & rewelding as well as "massaging" the pipe to create clearance. It works fine unless I hit something about speed bump size at a speed of around 25mph or higher so it doesn't happen frequently. I wasn't happy with the quality of this work for the price they charged.

I previously had a shop put on an aftermarket manifold and replace the rear cat and they didn't replace the hanger on the rear cat so that's likely contributing to the problem on mine.
 
-T. said:
I had the exact problem with aftermarket cats. I beat the exhaust up pretty badly and, I think, that beating caused the cats to fail again. Lesson learned. I bought a slightly more expensive set, and the bends were much better as fars moving the exhaust up and away from the front driveshaft. The 'better' exhaust was a Pacesetter, also purchased from Ebay. I don't recall the first one, but I believe I picked it up from Rock Auto. You can see in the pic that the new set up (front) th rear pipe runs upward, away from the driveshaft. View attachment 79145

So, yeah, I am afraid you are probably just dealing with same issue I had. I'm not sure what else the muffler guy can do with it aside from replacing the section of pipe, which might get cost prohibitive. Good luck. Like I said, with mine, it wasn't long before the catalyst cracked again and started creating problems, so I never had much opportunity to come up with a work around. -T.
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Since you have installed the Pacesetter cats any issues with them? Good seal at the manifold, Good seal on the second pipe connection and the muffler flange connection? Do they hit the oil pan or aluminum lines? Also I notice they don’t have heat shields like others do any issues with that?
I know these are made in the U.S. any feed back would be helpful looking into buying these.
Thanks in advance
 
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