Hello all. Thought I would put this in a separate post from my engine rebuild post, since it's a specific issue.

Trying to loosen the two bolts that hold the exhaust manifold flange together with the tailpipe flange on my S6 225.

I have been soaking the bolts in Liquid Wrench for a week, and the best I've managed to get is that one bolt & nut are turning together - but not coming apart. The hex head of the bolt on this flange is large enough and close enough to the manifold throat, that I cannot get a box-end wrench over it. A socket barely fits over it, but because of the angle of the bolt, I have to use an extension, and I lose leverage because I have nothing to tug against, so the socket over the bolt head doesn't work. I've managed to grab the hex bolt head with the open end of a 5/8" wrench, but the bolt and nut are so rusted together, the hex head is actually flexing open the jaws of the wrench and allowing the bolt head to turn, when I grab the nut on the bottom of the bolt to try and turn it.

Regarding the earlier replies to this post in my engine rebuild thread, thanks guys. I will get some PB B'laster and give it a try. If I have to get a torch to try heating the bolts, I will but would prefer not to have to go that route if possible.

Is there something else I could try? Would an air hammer/socket combo spin these apart any easier? I still have to grab one end of this nut/bolt combo to get them apart and it's a little awkward.

Anything I could try to make this process easier, I will do, even if it does involve the torch. I have to keep the project moving along and this is holding me up. It seems like there's more options I could try, but I can't think of them.

Thanks guys.

Probably a reason why no one else has said this but eh, why not grind them off?

I can't remember if the pipe flange itself is threaded or not, but since yours is held together with nuts and bolts I would assume that yours is not, in which case you could definitely just grind them off and be done with it.
Do you have an impact gun? I'd try that before grinding, it would almost definitely zap them off. You'll have to hold the bottom nut with a wrench of course--a helper might be a good call.

Try a Dremel tool, or air grinder. Mabey heat the bolt with a torch and when its still hot but not red hot spray with some PB Blaster, then try to break it loose.
Sorry for the suggestions and no hands on help. Im at the other end of CA .

_________________
Fast is fine but accuracy is final. You have to learn to take your time ... in a hurry
- Wyatt Earp

yes-- if they are just bolts-- cut them off---
as for pb blaster-- someone posted a mixture of acetone & tranny fluid worked better than any aftermarket loosening agent. Lawrence

I have a Dremel. Will need to check to see if I have a cutting wheel in my tool kit. How (from what angle) do you all recommend trying to cut off the bolt? Thinking of getting an impact gun as that would be useful for future needs. But trying to keep expenses down.

Just use the blue wrench and burn them off. Burn the nut if possible; its easier to remove without damage to the flange than burning the screw head. Use anti-seize on the threads of the replacement fasteners.

Ken

I can't even explain to you how much an impact helps. Even just a "cheap" electric gun is a life saver. I think the one my dad got at Christmas was about 100 bucks.

Worked on the manifold today. Started using the Dremel with a cutoff wheel. Realized the futility of that after spending 20 minutes and seeing the results (or lack thereof). It's a great, versatile tool but not well suited to getting the task done quickly.

In my cadre of tools, I have an acetylene torch (not an oxyacetylene torch, just acetylene), and I have a propane torch. Tried heating the nut with the propane torch, but just wasn't getting anywhere. Don't know if the flame wasn't clean enuf, or hot enuf to really heat the nut but didn't seem to make a difference in tugging on it further. Since I don't have the oxygen component and mixing gauges for an oxyacetylene setup, I didn't have the wherewithal to use that to cut the bolts off. What is an acetylene-only torch good for? A relative used to do plumbing work, but abandoned it for years, so I took it. Have yet to find a use for it.

Took a trip to Harbor Freight and picked up a 4" angle grinder. That ended up doing the trick. The RPM's are not that high, but slapped a cutting disc on it and took to the nuts. Managed to cut them off, but of course, not without slicing into the tailpipe below the flange. Damn. I'll have to weld that. And of course, the stupid transmission cooling lines were right in the way. Those brass hex fittings on the ends get so tight, it seems nearly impossible (unless you've been soaking them in LW or P B'laster for 24HRS) to loosen them without damaging and bending the line, which I did, so I just cut the line off.

*sigh*. Plenty more for another day.

The culprits