986 S exhaust troubles - 986 Forum - The Community for Porsche Boxster & Cayman Owners

tonythetiger · 04-30-2020, 01:54 PM

I am at wit's end...several days in, many hours invested trying to remove the center pipe from the flange of the exhaust manifolds. One bolt on the top is welded in, nothing on the other side...corroded away, one nut and the protruding stud on the bottom is snapped of and one nut came free.. I can't get the flange free. cant get the studs to budge.
penetrating oil and torch have proved ineffective.
anyone have any advice? I am scared to attempt removing the manifolds, although the bolts look pretty good, surface rust and such.
Look at this debacle.
If I go for the manifold bolts, how do they look and what should I do to insure I dont snap those off?
should I consider cutting off the flange on the rear side and replacing the back cat pipes?
something gotta give.

rfuerst911sc · 04-30-2020, 04:21 PM

What kind of torch are you using ? At a minimum use Mapp gas but preferably oxy acetylene . Get the nuts/bolts cherry red and then slowly loosen . Between heating cycles hit with kroil or PB Blaster . Go slow and methodical and you shouldn't break anything .

tonythetiger · 04-30-2020, 04:58 PM

Quote:

Originally Posted by rfuerst911sc

What kind of torch are you using ? At a minimum use Mapp gas but preferably oxy acetylene. Get the nuts/bolts cherry red and then slowly loosen . Between heating cycles hit with kroil or PB Blaster . Go slow and methodical and you shouldn't break anything .

Oxy/acetylene, pro setup. there is no substitute for this since a map gas torch isnt hot enough... and I'm no newbie on this. I have never had bolts not come loose, never had them shear off but not come loose.
this is ridiculous.
one sheared off, cannot extract the stud, the other came loose (the nut) but can't remove the stud and the other is welded in, everything is rotted off on one side and will not come out. the entire flange is stuck and wont come loose.

I am considering cutting this thing off, but I will still have pieces of the flange that could just be hopelessly rusted together.
Never, never, never saw anything like this before in my life.

tonythetiger · 04-30-2020, 04:59 PM

really curious about trying to pull the manifold off, should I heat the head or the bolts?
ive never pulled manifold bolts out while on the car.
is there a danger that I will distort the head and ruin my engine?
any tips out there?

rfuerst911sc · 05-01-2020, 02:49 AM

Pulling the manifolds I would be careful applying too much heat , instead I would take a long punch and hit them in the center of the bolt head . You are just trying to shock them enough to make it easier to break them loose . As you know breaking these bolts in the head will make your life more miserable . Spraying some PB Blaster on the bolt heads and tapping them with a punch/hammer may get enough penetrant in there to help . Good luck I feel for you . And of course when you do get it apart apply anti-seize to all fasteners .

itsnotanova · 05-01-2020, 04:12 AM

I can't see why it won't come apart. Even with broken stud, it should come apart. I'm thinking a tap of a hammer might loosen the bond between the two mating surfaces. What really scares me is that if those bolts are that difficult, the the bolts holding the manifold onto the head will be even worse.

tonythetiger · 05-01-2020, 03:23 PM

OK, we had success! it was pretty brutal, but it is done and I think I've earned myself the fabspeed 2nd cat delete pipes to replace the mid-pipes and muffler. passenger side took forever and I was forced to drill out the stud (this should be done from the front looking back) and this lossened every thing, then I melted the remaining studs and wiggled the secondary pipe off. Driver side only took about 15 minutes. I heated 2 bottom nuts red and creaked them off with a socket. Pipe was still stuck rock solid and I melted the top stud while wiggling the pipe. It broke free and the pipe dropped off. the remaining stud in the top hole was still in the manifold/header flange, but pounded out once I cooked the weld on the front. there is a little distortion (elongation of the hole) on the passenger side flange of the second pipe, but dont think that will make a difference, plus, I am kinda serious about the fabspeed upgrade, so...:+)

tonythetiger · 05-01-2020, 03:34 PM

quick question...should I reuse the old hardware or pop the new stuff on?
:+)

Traco · 05-02-2020, 12:04 AM

I replaced those flange gaskets last year as it had a leak. They were a nightmare to separate and in the end it was an air chisel that split them in a matter of seconds.

I didn't replace the clamps on the U bend pipes but will do this year. The new ones will make like simpler in future rather than fighting with a rusty tired one again.