rusted manifold bolts?

SAshton

SAshton

Member
Nov 30, 2007
416
somerset, mass
Boat Info
2004 280 Sundancer
Engines
Twin 4.3 w/A1 drives
I have a few that you can't even tell there's a bolt there. I uses PB Blast on them ALOT and chizzeled the crap surrounding the bolt. I spent 2 hours on this so far. What are some ideas on the best way to deal with this? I can't get a good grip even with a metric socket. 1998 7.4 L MPI. I definately am not removing the engine to do this so that out. Maybe drill the bolt heads,(if I can find them) or try the sockets made for rounded,striped bolts.
__________________
 
Stop messing with the heads on those that are rusted since you don't have clear access for vice grips to work. Get some impact sockets and pick one that is slightly smaller than the rusted ones and drive them on the heads then use your rachet to remove those you can. On those you cannot make that approach work for, get a hand grinder and grind the head off. Once all the bolts are removed or the heads ground off, the manifold easily slips off over the remaining bolts. Once it is gone, you can get clear access to the remaining part of the bolt and use vice-grips, a stud remover or a pipe wrench to remove the bolts.

A word of caution.........be careful with the remaining bolts and don't break them off down in the head.
 
hmm.... Do you have the ability to get a compressor and air impact wrench to your boat. No guarantee but I have had some nuts that only came loose with air impact wrench. Heat from a propane torch is useful on old cars for breaking loose rusted bolts but I'd plan really carefully resorting to that unless I felt that it seemed safe. I have spent sometimes over an hour removing one bolt on my 35 year old Lotus Europa. Sometimes you just have to walk away, and rethink a new approach. Can you add any leverage with a breaker bar or even an extra foot of leverage with a pipe over your ratchet to extend it.
I usually go:
PB Blaster
leverage
heat
bang on something with a hammer
repeat the whole process
if all else fails then cut

Eddie Zuskin
 
just re read your post. Can you reshape what bit of head there is with a Dremel type tool to get some type of socket on it?
Eddie Zuskin
 
If the bolts don't budge, nut buster fluid and/or a torch will work. Last Spring, I had to get the manifolds off to do an upper engine rebuild (I had a stuck lifter!). A newer starboard manifold (2 years old) came off easily. The port side manifold could not be removed by a prior owner's mechanic, but I had to get it off! Several of the manifold bolt heads were stripped, and one was snapped off (Thanks to the mechanic!). I got one bolt off with a Craftsman backout socket set. Several I had to grind off the head with a Dremmel drill and grinder disk tip. The manifold was shot and needed to be replaced anyway! Once I broke the manifold away with some chisels, I soaked and torched the bolt studs, clamped on a vise grip, and was able to turn off the studs (Thank God!).
 
Well I used Matco Bolt extractors and I got to all but 1. I am going to grind the head off that one with a dremel tool. PB Blaster is one very good product. They all came off with not much pressure the problem is getting a socket or whatever on the rusted and deformed bolt heads.
 
please be careful of your fuel lines if heating with a torch.
 
Got this from another site and since it wasn't mentioned in this thread, thought I add it for historical reference. It wouldn't work for me as I don't weld...but I found the idea to be an interesting one.. I also wonder how much weld would you need so that the weld joint wouldn't break?

"If a bolt is really proving to be a problem (some have very shallow heads and round off in no time), one option if you're handy at welding is to weld another nut on to the head of the bolt, and use that to swing on with a spanner - but only try this if you're welding is top notch and you can join the two up perfectly. A splatterly bobble of weld tacking the two together probably won' t be enough."
 
I really have to question the advisability...perhaps even the possiblilty of welding a nut on the manifold bolts on a 7.4 Mercruiser while the engine is in the boat.......welding on a rusty bolt requires a general purpose fluxed rod with pretty high amperage, not a wire (mig)welder, so there would be welding spatter going everywhere and getting on everything. Also, you are going to be welding inside the nut which means the rod and rod holder must be almost perpindicular to the head.......is there room for that?
 
I grinded the head off with a dremel tool. It took 20 minutes or so. I was a little nervous with all the sparks flying but I made it.
 
I see you have already solved your problem, but I have had to wrestle with this before, and I came up with a pretty good solution, albeit not entirely my own ideas.
1. Take a hole saw slightly bigger than the heads of the bolts and root out all the cast iron metal around the heads, this breaks up the rust and gives you more room to get a socket on the bolt head. It also destroys the whole saw and the manifolds, but you aren't going to use them again anyways.
2. Then use a generous amount of PB on each bolt.
3. Go home and drink a beer or 2 and tell everyone how difficult your job is. It really does help to let them sit a while.
4. The next day spray some more PB fluid around the bol heads.
5. Take a metric socket slightly smaller than the bolt head size and pound it onto the bolt.
-OR-
use one of those sockets for stripped bolt heads that you can buy from Sears or some auto parts stores now. I think I even saw them at Lowes.
6. Use a long handle ratchet and back them out.

I got all of mine off in now time after I used that technique, however it took me several days to come up with it.

briman
 
sashton:
what attachment/wheel did you use on the dremel and where'd you get it? how many of these attachments did you go through to cut the head off each bolt?
 
I used the grinding bit from sears. (rounded thick circle about 1/2 inch-orange bit) If you need the exact info I still might have the box that the bit came in.I only had to use it for 1 head and it's beat. So I would guess 1 bit for 1.5 maybe 2 bolt heads. It worked better as it was wearing down due to the tight fit on a big block.
 
I always use those little round cut-off wheels that fit in the demel tool.

First try all the obvious steps, leverage, penetrating oil, heat, hammers, etc. Then use the demel disk to cut a slot in head for an impact screw driver. If that doesn't work turn the demel and cut the head off.

409_pd.jpg
 
Someone makes a better cut-off wheel than the Dremel Al-Ox one above. I bought several packs of them at a Black & Decker Store, but I can't find a photo of them on the net. It is a fiberglass impregnated wheel that will not break and fly apart if you get it in a bind like the Al-Ox Dremel wheel is prone to do. They fit the dremel mandrel but are slightly thicker than the Dremel wheel.
 
I tried the cutoff wheel but it was to big so I used a grinding bit. It was alot smaller and 1/4 inch thick. perfect for the bolt heads
 
How did I spell dremel wrong three times in a row?

Frank, if you go to site where I got the picture:

http://www.dremel.com/en-us/attachm...tachment-accessory-group.htm?H=188549&G=66367

They have the fiberglass reinforced wheels as well. I've never tried them, I still have about 100 of the one in the picture. But, I will try the fiberglass ones because the other ones do fly apart.

SAshton, if grinding works, great. Over the years, I've used a drill as well to take a bolt head off, just drill straight down. But these little cut-off wheels are less than an inch across and the fastest thing I've used in close quarters.
 
What Frank said.

When I did my manifolds, some bolts came out without problems, others I had to use a smaller impact socket pounded into place. The rest I cut off with the fiberglass reinforced dremel wheels.

I thought about bringing the welder down and welding a nut over the bolt, but didn't want to put that much heat into a gasoline engine room. BTW, Frank, flux wire works for 1/2 or so bolts. I usually use a nut and weld inside the nut's hole to the bolt head. But not on a gas boat. There's not enough room to work with a welder safely, even a wire feed welder.

Best regards,
Frank
 
Honestly, I think its the heat created by welding that makes bolt removal after welding a nut on the bolt head work.

Frank- my wire welder is a 250A Miller and is too big to haul to the boat and changing the set up to a fluxed wire is a PITA. Its my mistake, but I guess I assumed everyone had a big welder with an Argon bottle to deal with.
 
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