Unseizing techniques

[knitchie]

Due to a leaking muffler and exhaust pipe, I am replacing my hot section and muffler. Cutting the hose between the hot section and muffler, and removing the manifold from the engine were easy. But, the two bolts holding the flange to the manifold and the hot section thread to the flange appear to be fused beyond my initial to ease them to unthread. Might be 30 years of heat and rust.

I have soaked the threads with PB Blaster all weekend with little effect. The bolt heads have been stressed to the point where I will round off the edges if I force them more. I probably need to find a more solid support to clamp the manifold to in order to get better leverage on the hot section pipe; my bench is bending as I haul and tap on the joints.

I'm trying to avoid destructive disassembly. Not sure how I'd remove the bolt threads if I cut the heads off. Might cut the hot section just behind the flange and try to cut the pipe out from the inside, but not sure how that works.

Obvious question: What tools and techniques do I need to add this effort?

[ArtJ]

I am not a expert on this, so please take this from whence it comes.
Since you have the manifold off, is it possible to heat the flange (carefully
so as not to crack it) with a Torch and then try to remove bolts?

Not sure if this is a ok thing to do or not.


Regards

Art

[hanleyclifford]

First of all a solid bench vise. You might be able to accept the permanent joining of flange to manifold IF you are able to cut the threads out of the flange AND have a 1 1/4" NPT to rethread/chase the flange. I personally prefer the option of destroying the present flange including the bolts and rethreading the manifold for studs and nuts (3/8" x 16 NC). Upgrade to the new MM flange with pressure test port.

[msmith10]

I agree with Hanley. I did this job last year. No amount of heat, impact or PB Blaster was going to allow me to remove the bolts holding the flange to the manifold. Even cutting the heads off the bolts was useless as the bolt shafts were still welded to the holes in the flange. I ended up cutting the flange off with a thin cutting wheel on an angle grinder, then drilling the bolts out of the manifold and cleaning up the threads. Also, don't even attempt the job without removing the manifold.

[knitchie]

Unseizing techniques

Thanks guys! Tried a little heat, but maybe need to use more repeatedly.
Specifics on "drilling the bolts out of the manifold and cleaning up the threads"? I've seen warning on this site about using stud removers. Or, is this a "take it to a pro" job?
Ken

[ndutton]

Maybe try a number of heating and cooling cycles before torquing the bolts. I'm guessing that might break the bond for starters.

[ArtJ]

Maybe try to get some pb blaster to draw in to the heated flange?

[Dave Neptune]

Has worked 4 me

knitchie, an alternative! You will not extract the tapered pipe from the flange so you will need to replace it.
Grind or cut the heads off of the studs or bolts in your case and you should be able to worry the flange off with a hammer and a flat head chisel. When that is off the remaining stud or bolt will be exposed and you may be able to knock the rust loose by a few good hard-raps directly on top of the remaining studs or bolts. Many time by smacking the offending threads against the direction they were holding will get them looose so with minimal effort you can extract them.
I would take a long look at the manifold to see that it isn't about to rust out. If it is may as well bight the bullet and make the job an easy one.

Dave Neptune

[Al Schober]

My suggestions would be:
1) First, cut the pipe off leaving about 6" from the flange.
2) Cut the heads off the bolts. Hacksaw followed by angle grinder.
3) Lever the flange with pipe off the remains of the bolts. Don't be afraid to beat on the pipe - you might just loosen it up. Try to save the manifold. If you damage the manifold, just replace everything!
4) Once the flange is off the manifold, cut the pipe off to about 1/4". Working from the inside, put two saw cuts in the pipe about 1/4" apart, trying to cut only slightly into the threads of the flange. Drive out the 1/4" strip of pipe, collapse and remove the rest. Cleaning the bolt holes with a drill should give you a workable flange.
5) Try removing the remains of the bolts from the manifold with a vise grips or a pipe wrench. If this fails, you'll have to cut them off flush, then drill and re-tap. If the re-tap fails, you're into heli-coil inserts.
Oh yeah, try not to hurt yourself. Gloves and safety glasses (with side shields) are good things. It beats trying to explain why you weren't wearing safety glasses as the opthalmic surgeon digs a chunck of rust out of your cornea.

Al

[smosher]

I took it to a machine shop and they charged me $ 20, after
I spent many hours trying to get the bolts out

worth every penny.

[JOHN COOKSON]

Yet Another Approach

Get a six point socket and as long of a breaker bar as you can find. Apply progressive steady even torque up to about 90% of your strength. Tools tend to slip if you go for 100% torque.

If the bolts don't loosen (which they probably won't) try:
Hitting the end of the breaker bar with a hammer
or putting a piece of pipe on the end of the breaker bar.
Keep at this drill untill the bolts come loose or the heads twist off.

If you have trouble holding the part firmly jack up a tire on your land vehicle, put the part under the tire, shore up with wood as necessary, and let enough weight down to hold the part.

If you don't attempt the absurd you will never achieve the impossible.

Have fun!

TRUE GRIT

[Dave Neptune]

Wow good idea!!!!

John, I love the "tire vise" that's a new one to me.

Dave Neptune

[knitchie]

Unseizing techniques

Thanks everyone! Glad to report that the last bolt broke free last night.

I gave up on unthreading the exhaust pipe and just cut if off near the manifold flange so I could get sockets on the bolts. But, still no luck after several heat and PB Blaster sessions. So, I ground out the washer/shoulder under the bolt head with my dremel until I saw the hole in the flange. Although I could only get 2/3 of the way around, this was enough, after more heat and PB Blaster to free one bolt. Unfortunately, the bolt head of the second bolt twisted off, but this allowed me to remove the flange and expose the rest of the bolt. More heat and PB Blaster, as well as flattening opposing sides of the bolt, and tapping the end and sides of the bolt repeatedly for three days, and the bolt finally succumbed to the leverage of a large wrench.

Next is an acid wash before painting the manifold and reassembling the entire exhaust system. Life is good!

[hanleyclifford]

Now check out the stud kit in the online catalogue - and never go thru that exercise again!

[Raymond]

Unseizing techniques

Happy New Year to all.

I have a 1975 Catalina 30 with the original A-4. I discovered some shavings directly under the cooling water exhaust entry. The exhaust is still wrapped at that point, so I wasn’t sure of the origin of the shavings.



Time to unwrap and think about replacing the hot exhaust. For the past month, once or twice a week, I have squirted the bolts at the exhaust flange with PB blaster, hoping to loosen them. I am still at that stage; they haven’t budged. Then I read this thread and think I’m getting into more than I’m ready for. Do I really need to replace this?



Will I have to remove the manifold?

This is the original setup.




Assuming I can get this apart, I am thinking of using Product No. - EXHT_01.2_334 T-type cooling water exhaust entry fitting with an elbow immediately below the T. I am not sure that that elbow would still be above the muffler inlet.

I appreciate any thoughts anyone has. Thanks