Got the old Y-Pipe out. Dang, both cats rattle like crazy.

Question about the bolts. They were a complete pain in the **** to get out. 5 of them came out with the studs instead of the nuts coming off. one of them the stud started backing off then the nut came off so I assume that the stud is only partially in.

I had to use 2 extensions to get to the right side.

should I replace the bolts? Scared they may be weakened since I had to impact the hell out of them to get them off.

when putting back in, do you put the nut on the stud then drive them in? Should they be locktited and torqued to a specific spec?

 

Yeah, um...

My guy never dropped the Y-Pipe, he just cut out the cat, and installed the new one with everything on the truck. Took him less than 20 minutes.

 

You didn't have any of your exhaust manifold studs break off!
You are one luck guy, I always end up having to pull off at least one manifold to remove broken studs.
I would use all new hardware it it was me.
They even make bass nuts so they are easier to remove next time.

 

warm the engine up before removing them also hit the bolts with some pb blaster. Advanced auto sells the studs and matching bolts in the quick repair section.

 

Thanks guys, got some brand spanking new copper plated studs, nuts, and gaskets on the way. I guess I am real lucky non broke.

Is it a good idea to run a tap up into the holes to clean up the threads? What is the size and pitch?

 

i have the magnaflow as well, it bolted up but was a tight fit when aligning the muffler section to the y-pipe and took some brute force

 

Got the magnaflow in. There were no bolts to connect the Magnaflow system to the cat back part. The flange on the ypipe/cats I am replacing has the old bolts that look like they are mounted to the flange.

What bolts did you guys use?

 

" I guess I am real lucky non broke" YES VERY LUCKY!!!! No $hit....Go play the lotto!


" What is the size and pitch? " M8x1.25 and the part # for the stud is ERR551. Depending on which stud came out, I would use a bolt and full metal lock nut if you can reach it from the top. I've done it many times. Those studs are a HUGE PITA when (not if) they break.

 

Thanks for the reply. I actually already went through the PITA part of removing the front pipe studs and have new studs with anti seize in place. I was referring to the bolts on the flange that connect to the cat back/muffler pipe.

I just went to the auto parts store and bought a flange with bolts in the kit. A little long, but at least they are made for exhaust and will withstand the heat, I HOPE!

 

I'd personally go with the Magnaflows.

You've got two options:

1.) You can either buy two universal cats from Advance Auto (you can get a big discount if you order through their website, or if you ask they may give you the same discount in store) and chop out the old ones yourself. Drive your truck to the exhaust shop and have them just weld the new ones in (it's a loud ride, but it sounds pretty sweet). I did this and it costed me about $45 in labor, $75 for each cat, and then you can take your old cats and recycle them. I think I got $40 back for each.

2.) You can order the direct fit Magnaflow y-pipe. You will also need new manifold to exhaust gaskets. Install it yourself, which should be a fun job, but more expensive.