Exhaust manifold to pipe bolts | Ford Explorer Forums - Serious Explorations

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Exhaust manifold to pipe bolts


"I'm counting to 3, then I'm getting your dad."
Elite Explorer
March 16, 2013
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City, State
Woodstock, GA
Year, Model & Trim Level
04 Ford Explorer 4.6l
Has anyone successfully removed the bolts from this location?
They appear to become part of the manifold at this point.

With the engine out, I figured now was the time to replace the gaskets. Here and at the cat.


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Those replacing the clutch in manual transmissions have removed them regularly, since the Y-pipe needs to come down to get the trans out. Those with auto transmissions have to get them out for a rebuild, too.

If the engine were in, your best bet would using a long 20-24" extension (so you can lie down on the ground without having to sit up in an uncomfortable position, and so you have the full range of motion away from the Y-pipe and transmission) and a breaker bar/flex handle to pop them loose, then a long handle ratchet for enough leverage to keep up the torque when loosening them. I've never used anything other than 3/8" tools to get them out, I think using 1/2" tools would be overkill and you might break the bolt off rather than break it loose.

With the engine out, you can probably just use a breaker bar and socket while standing in the engine bay.

I'd highly suggest squirting some spray penetrant like PB Blaster on the threads from the top so it makes it's way in there. Putting it on every few hours over a period of days before doing the job can make busting them loose a lot easier. You should also squirt a little on as you go, and work the bolts loose rather than just go at it. Turn them back clockwise after you get a turn or even half a turn. Once they come out a bit, spray the penetrant on the threads from that side, then turn them back in, loosen, spray more penetrant on, and repeat. You might also want to take breaks and let the bolt/manifold cool down, if you just work a bolt back and forth too long, it will be very hot from all the friction, and that can help it break off as well.

I've been able to get them out every time, the first time was the hardest since they seem to lose a little material each time they come out. If they are too badly rusted or the threads are damaged, you can get new replacements from Ford. You can also use regular hex head bolts with the same thread pitch, but I prefer using washer head bolts, since they really help when re-installing the Y-pipe. Regular hex bolts, even with loose washers, don't really cut it. You also really need to use the same class (grade)bolts here, not just low-grade cheap stuff.

You should be able to replace the manifold gaskets without having to remove the manifolds from the Y-pipe. If you're thinking there is some kind of gasket between the manifold and Y-pipe, there isn't. It's a metal-to-metal press-fit circular flange seal, and the rust and crud seals it up airtight. The only other gasket besides the manifold-to-block gaskets is the oval gasket between the Y-pipe and the catalytic converter.

So you are saying that between the exhaust manifold and exhaust pipe, there is no gasket?

I know there isn't between the manifold and heads. I just figured there was a donut at the pipe. Haven't actually looked from any other angles. If there's no gasket, then there's no reason to pop the bolts.


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I didn't see a gasket when I disconnected that pipe, on either side. Course, the exhaust had been removed previously by the PO for a transmission rebuild.

For those bolts, I did what Anime suggested, got at them from underneath with some long extensions and an impact gun. The trickiest was the one on the passenger side. Having a u-joint adapter helped greatly and make sure your air compressor is full and not regulated, you'll need all the help you can get.

Your motors out so you'll have an easier time breaking it loose. Soak the threads for a couple days as suggested with some PB Penetrating spray.
May even heat if up with a torch of you have one.

People with automatic transmissions do not have to drop the Y pipe to get the transmission out.

So help me with my thought process.

I was only going to remove the y-pipe to replace the gaskets. As it seems next to impossible to do with the engine in.

If there's no gaskets, then I really have no need to remove it.


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There is no gasket between the y pipe and manifold.

However, since you have easy access now, it might be worthwhile (if you have nothing else to do) to break those bolts loose, run a tap through (and a die on the bolts unless you get new ones), goop the hell out of it with anti-seize and put it back together. The anti-seize won't last terribly long with the heat but it might help you out if you have to pull heads or drop the exhaust in the future.

I can get a new y pipe cheap. Same with bolts and springs.
I'd thought about it like you said. Perhaps using a high temp grease to coat the exposed threads.

Any time I work on exhaust stuff I replace the steel nuts and washers with brass or bronze. They won't seize onto the steel threads being dissimilar metals.

So help me with my thought process.

I was only going to remove the y-pipe to replace the gaskets. As it seems next to impossible to do with the engine in.

If there's no gaskets, then I really have no need to remove it.

It's not impossible at all. Like I said, plenty of us have done it on our Explorers, multiple times, to drop the transmission. I've done it several times and it gets easier each time.

There is no donut gasket. It sure looks like one, but the 'donut' is metal and part of the exhaust manifold:


The flange on the Y-pipe just pushes against it due to the pressure from the bolts and it makes a pretty tight seal. There is usually anti-seize type crud on the flange that helps it seal, and any minor leaks are eventually sealed up by rust and exhaust buildup.

You can just leave it alone and not bother with the connection if you don't want to mess with it, but you might also consider this a good chance to get at it and pop the bolts out and at least clean the threads and give them a very light coat of anti-seize so they come out easier if you ever have to drop the transmission.

If you plan to seperate the catalytic converter from the Y-pipe to replace that gasket, you can do that by just seperating the muffler from the converters, then dropping the Y-pipe and converters as an assembly, then seperating them off the vehicle.

I just came in to find a similar answer. On my barn find '94 Navajo, there are no nuts, springs, or anything on the header to Y pipe connections. Two of the bolts, one on each side, are actually flush with the manifold flange. They look a tad rusty. I'll be doing the PB pre-treat of course. The CAT to intermediate pipe actually look worse. Those might need to be cut off. TBD. I bought a bolt kit from O'Riley that has bolt, washer, spring, and nut tab for the header to Y pipe. I hope those are right.

This is stupidest design ever. In old days there were threaded studs going into the exhaust manifold. The flange fit over the studs, and you used BRASS nuts to tighten it down. The brass nuts wouldnt rust to the studs nor do they rust to some little nub that you cant grab onto. They were also smart enough to use a replaceable donut gasket. Perhaps even used some springs so there was a little play allowed. Using nuts, if nothing else you can split them to get them off then just replace them for next to nothing.

When I went to remove my y-pipe, there was enough rust nothing could get hold of the head of the bolts. I cut bolts where they were exposed at side with die grinder, got the y-pipe out of the way then cut them flush, but left the end of bolt sticking out other side. I then welded up some clamps, one end cupping over that bit of bolt still sticking out. There is still little bit of a leak but not enough to be annoying. Think of my homemade clamps as sort of a permanent one use c-clamp. Cheap, just made out of half inch diameter bolts and nuts. There is something similar sold commercially but they are $$$.

Now if you have an oxy acetelene cutting torch you can just pop the bolts out, leaving holes and then use regular bolts with nut on end. If engine is out of the truck you can cut slots with die grinder into the manifold flange and again use regular bolts and nuts.

You cant really drill the bolts out unless you have lot better drill bit than you will find at most hardware stores as these are hardened bolts.

I would suggest you could remove the whole manifold but Ford again bolted it onto the head rather than using studs and nuts. These tend to break off. Plus with engine in truck its hard to get much leverage and room to swing breaker bar. But break off the manifold bolts going into the head and you will be a VERY unhappy camper. Its expensive getting this repaired, probably cheaper just to buy set heads and manifolds at junkyard, lap the valves and install those.

when I tried to remove cut off bolts between manifold and flange had to go to machine shop and bored them out on same plane on made gig and end mill can't find studs or brass nuts to replace I guess i'll just anti seize hell out of bolts

I'm treating with PB Blaster now. I'm a bit concerned after what @Coasting2aStall said above. I don't have a torch, just MAP gas, angle grinder, and a BFH. I'll have to see how it goes once I finish cutting off the cat pipe just downstream of the flange with 3 bolts. Those are toast. Making room so I can work, and drop the Y pipe. If I can't get it off the manifolds, then I'll just cut the bolts off of the flange to the cats and go new from there. TBD.

If your looking for brass nuts try a hardware store or a marine store like West Marine. Boats use lots of brass and bronze hardware.

I like to use transmission fluid and denatured alcohol or
You can use acetone in place of the alcohol
I prefer alcohol it stays mixed longer

50/50 mix shake well


Here is the sort of commercial version repair clamp I used, only as say, I have an arc welder and could weld up my own out of half inch bolts for next to nothing. Be aware you dont have lot space to work with on the two outside bolts, pretty close to frame, but it is doable.


NICKSON INC 17350 Clamp: manifold stud; Clamp-A-Stud; size 1/4 inch to 1 3/4 inc

I also didnt do an exhaustive search (pun intended), probably cheaper versions if you spend time searching.

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