Flex pipe fun - pt1

It's been a while since my last dispatch.  The Freestyle hasn't been on the road for the last six weeks due the following:

1. The exhaust was leaking, this needed to be fixed for PA state inspection
2. Things have been nuts on the home front, preventing me from tackling item #1
• Christmas!  I took some time to bake cookies (from the excellent Christmas Cookie Book from J. Knipe and a few of my own concoctions I stash in the front material)
• Some work travel
• Other stuff, I won't bore the reader. 

Now, things have calmed-down, giving me time to address item #1 on the list, that pesky exhaust leak resulting in the car sounding loud enough to attract onlookers.  I'm not a fan of exhaust work.  Yes, it's basically plumbing for air; it just seems to be the collector of all things rusty and stubborn -- as proven by this job.

 Here's what what we had under the car; the problem was easy to spot. I put a screwdriver into the void on one end to give some idea of the extent of the break in the line, but it looks like both ends were corroding.

In order to pass inspection in PA, this issue must be fixed by replacing the part, this is issue is just a tiny bit beyond a duct tape solution.

Somebody did this repair once before, replacing just the flex pipe.  Instead of doing another repair, I sprung for a new Y-pipe connecting the two exhaust outputs into the single exhaust pipe out the back of the car.  Part of this Y-pipe was a new flex tube.  I don't weld, so removing and replacing the worn part as had been done already was something not on the table for this repair.

Replacing this pipe required me to free the old Y-pipe from all three of the cat-converters in the car.  Let's start with the connection to the rear cat converter.  How hard could that be?  More difficult than anticipated.  Let's see.

Removing connection to rear catalytic converter

Approach 1: Undo bolts with ratchet
Anticipated result: with some effort and penetrating fluid, the bolts would unwind
Actual result: Nothing moved, bolts stripped.  This was so boring, I didn't even bother to take pictures.  What made things a little worse was the position of the car didn't afford much in the way of leverage, maybe this would have worked if I were better positioned under the car?  Given the corrosion, guessing that the answer would still be nada.

Approach 2: Cut pipe with Sawzall

Anticipated result: A prince among power tools, equipped with a bi-metal blade will cut the pipe, no problem!  Will take more time to plug-in tool and attach blade than I'll spend slicing through the pipe. 
Actual result: Part hard to reach with blade, not much happened in the way of cutting.  I was surprised, I used the same type of blade to cut some exhaust pipe on my kid's car, I really wondered what was happening.  Maybe the pipe was shifting on the hangar and so the blade couldn't do any work?  Anyway, back to the next approach.

Approach 3: Rent cutting tool from auto-parts store.  $50ish deposit refunded when I returned the tool.

Anticipated result: The tool will work, because I don't know what else to do.
Actual result: Success!  This tool is a bicycle chain with cutting discs that wraps around the pipe in question.  After what seemed to be 100 back and forth motions, the pipe was cut.  The removed flange will be replaced when reassembling everything.

Removing the front connectors

Now, only two more connections, the ones to the cat converters in the front.  I'm 1/3 of the way though.  How hard could that be?  Each of the remaining pipes attached to a cat converter via an overlap fitting with tension provided a flange with a post bolt attaching to a corresponding flange on the y-pipe.  

Approach 1: Get socket, undo bolts.
Anticipated result: With some effort and penetrating fluid, the bolts would unwind.  Under all that corrosion, a nut was waiting to be twisted backwards over the threads it traveled more than decade ago.
Actual result: Nuts so corroded, I can't even get socket around a few, others strip after just a little pressure.  Bummer.  But, looking at the bolts, did I ever expect this to work?  Not really, but I figured it was worth a try.

Approach 2: Drill back side of studs to remove bolt
Anticipated result: Bolts will be removed from the inside out.  Use holes created by the drilling process for new bolts to anchor new part.  I really like the elegant nature of this solution, put new bolts in the newly created holes in the existing flanges to attach the new part.

Actual result: Too bad it didn't work.  Exhaust studs formed with hardened metal, lots of spinning with the drill, no cutting.  Tried cutting oil and fancy drill bits, no luck.  The picture shown is my attempt to drill out the bolt on rear cat converter, the picture for my attempt at the front flange was not focused correctly, the result is just about the same: after lots of drilling, a small divot.

Approach 3: Cut bolts with Sawzall

Anticipated result: I should have started with this approach.  Sawzall technology combined with correct cutting blade will cut the bolts right quick.
Actual result: Car too low to ground to fit tool underneath at a good angle.  After a bit of struggling, not much of the bolt was cut. 

Approach 4: Dremel + cut-off blade

Anticipated result: Dremel tool able to reach bolts and cut them.
Actual result: Smaller tool makes it easier for to reach the bolts and but them most of the way through.  The size of the cutting wheel does not allow me to to cut the entire bolt, but I get most of the way through.  Hardness of bolts quickly wears cutting wheels.  I have the right tool and have made great progress, the key is using the a bigger or harder cutting wheel, which must exist for the Dremel.  I hope.  Fingers crossed!

Approach 5: Dremel + better metal cutting blade

Anticipated result: Will cut metal better, because blade says it will cut metal.  Slightly larger disk will have more reach and will rotate faster, resulting in more cutting power.
Actual result: Success!  Most of the cutting was done by the prior tools.  The extra reach is what was necessary to cut through the remaining material.  The cutting process results in lots of sparks and I couldn't safely operate the camera to an image of the sparks showering from the cutting process.

This is what I didn't expect: the old part, now free, just fell off.  I was expecting the Y-pipe to be rust-welded to the remaining pipe.  This wasn't the case.  A nice surprise!

Here's the offending part next to the replacement part:

Other than the flex pipe segment, the part looks in otherwise good order. Closely examining the pipe didn't show any other leaks.  We'll cover the much less eventful installation of the new part in the next post.